tag:theconversation.com,2011:/ca-fr/topics/plants-1931/articlesPlants – La Conversation2024-03-25T12:39:22Ztag:theconversation.com,2011:article/2241522024-03-25T12:39:22Z2024-03-25T12:39:22ZWhat is dirt? There’s a whole wriggling world alive in the ground beneath our feet, as a soil scientist explains<figure><img src="https://images.theconversation.com/files/582688/original/file-20240318-24-77z9su.jpg?ixlib=rb-1.1.0&rect=0%2C9%2C3110%2C2057&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Dig into soil and you'll find rock dust but also thousands of living species.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/little-childs-hands-digging-in-the-mud-royalty-free-image/619539728">ChristinLola/iStock/Getty Images Plus</a></span></figcaption></figure><figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=293&fit=crop&dpr=1 600w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=293&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=293&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=368&fit=crop&dpr=1 754w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=368&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=368&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<p><em><a href="https://theconversation.com/us/topics/curious-kids-us-74795">Curious Kids</a> is a series for children of all ages. If you have a question you’d like an expert to answer, send it to <a href="mailto:curiouskidsus@theconversation.com">curiouskidsus@theconversation.com</a>.</em></p>
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<p><strong>What is dirt? – Belle and Ryatt, ages 7 and 5, Keystone, South Dakota</strong></p>
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<p>When you think about dirt, you’re probably picturing soil. There’s so much more going on under our feet than the rock dust, or “dirt,” that gets on your pants.</p>
<p>When <a href="https://arts-sciences.und.edu/academics/biology/brian-darby/index.html">I began studying soil</a>, I was amazed at how much of it is actually alive. Soil is teeming with life, and not just the earthworms that you see on rainy days.</p>
<p>Keeping this vibrant world healthy is <a href="https://www.youtube.com/watch?v=Qas9tPQKd8w">crucial for food, forests and flowers to grow</a> and for the animals that live in the ground to thrive. Here’s a closer look at what’s down there and how it all works together.</p>
<figure class="align-center ">
<img alt="Cupped hands holds soil against a dark background with a tendril of plant root dangling through the fingers." src="https://images.theconversation.com/files/582689/original/file-20240318-20-8yglsj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/582689/original/file-20240318-20-8yglsj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/582689/original/file-20240318-20-8yglsj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/582689/original/file-20240318-20-8yglsj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/582689/original/file-20240318-20-8yglsj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/582689/original/file-20240318-20-8yglsj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/582689/original/file-20240318-20-8yglsj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Soil is a vibrant ecosystem.</span>
<span class="attribution"><a class="source" href="https://unsplash.com/photos/bokeh-photography-of-person-carrying-soil-jin4W1HqgL4">Gabriel Jimenez via Unsplash</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
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<h2>The rocky part of soils</h2>
<p>If you scoop up a handful of dry soil, the basic dirt that you feel in your hand is actually very small pieces of <a href="https://passel2.unl.edu/view/lesson/c62dc027ae56/1">weathered rock</a>. These tiny bits eroded from larger rocks over millions of years.</p>
<p>The <a href="https://www.soils4teachers.org/physical-properties/">balance of these particles</a> is important for how well soil can hold water and nutrients that plants need to thrive. </p>
<p>For example, <a href="https://www.masterclass.com/articles/sandy-soil-guide">sandy soil</a> has larger rock grains, so it will be loose and can easily wash away. It won’t hold very much water. <a href="https://www.thespruce.com/understanding-and-improving-clay-soil-2539857">Soil with mostly clay</a> is finer and more compact, making it difficult for plants to access its moisture. In between the two in size is <a href="https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/what-is-silt.htm">silt, a mix of rock dust and minerals</a> often found in fertile flood plains.</p>
<p>Some of the most productive soils have a good balance of sand, clay and silt. <a href="https://www.masterclass.com/articles/how-to-create-loam-soil-for-your-garden">That combination</a>, along with the remnants of plants and animals that have died, helps the soil to retain water, allows plants to access that water and minimizes erosion from wind or rain.</p>
<figure class="align-center ">
<img alt="Three tipped over pots spill different types of soil – sandy is heavier grain, clay is finer grain and thicker, and loamy is darker." src="https://images.theconversation.com/files/581414/original/file-20240312-16-meqnvu.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/581414/original/file-20240312-16-meqnvu.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=371&fit=crop&dpr=1 600w, https://images.theconversation.com/files/581414/original/file-20240312-16-meqnvu.PNG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=371&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/581414/original/file-20240312-16-meqnvu.PNG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=371&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/581414/original/file-20240312-16-meqnvu.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=467&fit=crop&dpr=1 754w, https://images.theconversation.com/files/581414/original/file-20240312-16-meqnvu.PNG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=467&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/581414/original/file-20240312-16-meqnvu.PNG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=467&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Loamy soil, ideal for gardens, is a mix of sand, clay and silt.</span>
<span class="attribution"><a class="source" href="https://www.nesdis.noaa.gov/learn-about-soil-types">NOAA</a></span>
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<h2>The wriggling, munching parts of soil</h2>
<p>Among all those rock particles is a <a href="https://doi.org/10.3390/app10113717">whole world of living things</a>, each busy doing its job.</p>
<p>To get a sense of just how many creatures are there, picture this: The zoo in Omaha, Nebraska, boasts <a href="https://www.omahazoo.com/">over 1,000 animal species</a>. But if you scooped up a small spoonful of soil in your backyard, it would likely contain <a href="https://www.ceh.ac.uk/our-science/case-studies/case-study-why-do-soil-microbes-matter">at least 10,000 species</a> and around a billion living microscopic cells.</p>
<p>Most of those species are <a href="https://www.westernsydney.edu.au/newscentre/news_centre/story_archive/2018/first_soil_atlas">still largely a mystery</a>. Scientists don’t know much about them or what they do in soil. In fact, most species in soil don’t even have a formal scientific name. But each plays some kind of role in the vast soil ecosystem, including generating the <a href="https://www.aces.edu/blog/topics/farming/essential-plant-elements/">nutrients that plants need to grow</a>.</p>
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<a href="https://images.theconversation.com/files/581410/original/file-20240312-20-vn3j2x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Two centipede-like creatures caught on camera immediately after a rock is lifted." src="https://images.theconversation.com/files/581410/original/file-20240312-20-vn3j2x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/581410/original/file-20240312-20-vn3j2x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=439&fit=crop&dpr=1 600w, https://images.theconversation.com/files/581410/original/file-20240312-20-vn3j2x.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=439&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/581410/original/file-20240312-20-vn3j2x.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=439&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/581410/original/file-20240312-20-vn3j2x.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=552&fit=crop&dpr=1 754w, https://images.theconversation.com/files/581410/original/file-20240312-20-vn3j2x.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=552&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/581410/original/file-20240312-20-vn3j2x.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=552&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Lifting a rock reveals a symphylan, or garden centipede, left, and a poduromorph, or plump springtail, munching through the soil.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Symphylan_%26_poduromorph_springtail_(3406419924).jpg">Marshal Hedin via Wikimedia</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
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<p>Imagine a leaf falling from a tree in late autumn.</p>
<p>Inside that leaf are a lot of nutrients that plants need, such as nitrogen, potassium and phosphorus. There is also a lot of <a href="https://scied.ucar.edu/learning-zone/earth-system/biogeochemical-cycles">carbon in that leaf</a>, which holds energy that can be used by other organisms such as bacteria and fungi.</p>
<p>The leaf itself is too large for a plant to take up through its roots, of course. But that leaf can be broken down into smaller and smaller pieces. This process of breaking down plant and animal tissue is <a href="https://youtu.be/IBvKKMzXYtY?feature=shared">known as decomposition</a>.</p>
<p>When the leaf first falls to the ground, <a href="https://doi.org/10.3390%2Finsects11010054">arthropods</a> – such as insects, mites and <a href="https://www.chaosofdelight.org/collembola-springtails">collembolans</a> – break the leaf down into smaller chunks by shredding the tissue. Then, an <a href="https://youtu.be/n3wsUYg3XV0?feature=shared">earthworm might come along</a> and eat one of the smaller chunks and break it down even more in <a href="https://www.pbs.org/video/how-do-worms-turn-garbage-into-compost-jwj6cm/">its digestive tract</a>.</p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/2Pa1FwmKZcQ?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">PBS explores how earthworms help turn dead plants into fertile soil.</span></figcaption>
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<p>Now the broken-up leaf is small enough for microbes to come in. <a href="https://ohioline.osu.edu/factsheet/anr-36">Bacteria</a> and <a href="https://ohioline.osu.edu/factsheet/anr-37">fungi secrete enzymes</a> into the soil that further break down organic material into even smaller pieces. If enough microbes are active, eventually this organic material will be broken down enough that it can dissolve in water and be taken up by plants that need it.</p>
<p>To aid in this process, there are many small animals, such as <a href="https://www.canr.msu.edu/news/are_soil_nematodes_beneficial_or_harmful">nematodes</a> and <a href="https://www.livingsoil.net/protozoa">amoebae</a>, that consume bacteria and fungi. There are also predatory nematodes that feed on other nematodes to make sure they don’t become too abundant, so everything remains in balance as much as possible. </p>
<p>It’s quite a complicated food web of interacting species in a delicate balance.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/IBvKKMzXYtY?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">A time-lapse video filmed about 4 inches underground shows a leaf decomposing over 21 days in July. At the end, radish roots make their way down into the soil. Video by Josh Williams.</span></figcaption>
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<p>While some fungi and bacteria <a href="https://www.growingagreenerworld.com/bacteria-fungus-and-viruses-an-overview/">can harm plants</a>, there are many species that are considered beneficial. In fact, they <a href="https://www.nrcs.usda.gov/conservation-basics/natural-resource-concerns/soils/soil-health">may be the key</a> to figuring out how to grow enough crops to feed everyone without degrading and overburdening the soil.</p>
<h2>Figuring out your soil type</h2>
<p>Scientists have named <a href="https://www.nrcs.usda.gov/resources/education-and-teaching-materials/soil-facts">over 20,000 different types</a> of unique soils. If you’re curious about the <a href="https://www.nesdis.noaa.gov/learn-about-soil-types">soil and dirt in your area</a>, the University of California, Davis has a <a href="https://casoilresource.lawr.ucdavis.edu/gmap/">website where you can learn</a> more about local soils and their chemical and physical attributes.</p>
<p><a href="https://www.farmers.gov/conservation/soil-health">Caring for soil</a> to promote its living creatures’ benefits and minimize their harm takes work, but it’s essential for keeping the land healthy and growing food for the future.</p>
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<p class="fine-print"><em><span>Brian Darby receives funding from the United States Department of Agriculture. </span></em></p>Rock dust is only part of the story of soil. Living creatures, many of them too tiny to see, keep that soil healthy for growing everything from food to forests.Brian Darby, Associate Professor of Biology, University of North DakotaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2221082024-03-22T12:34:47Z2024-03-22T12:34:47ZClimate change is shifting the zones where plants grow – here’s what that could mean for your garden<figure><img src="https://images.theconversation.com/files/583569/original/file-20240321-20-wkg9tp.jpg?ixlib=rb-1.1.0&rect=6%2C0%2C4019%2C2474&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Climate change complicates plant choices and care. Early flowering and late freezes can kill flowers like these magnolia blossoms.</span> <span class="attribution"><span class="source">Matt Kasson</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>With the <a href="https://www.pbs.org/newshour/science/the-vernal-equinox-marks-the-first-day-of-spring-what-does-that-mean">arrival of spring</a> in North America, many people are gravitating to the gardening and landscaping section of home improvement stores, where displays are overstocked with eye-catching seed packs and benches are filled with potted annuals and perennials. </p>
<p>But some plants that once thrived in your yard may not flourish there now. To understand why, look to the U.S. Department of Agriculture’s recent update of its <a href="https://planthardiness.ars.usda.gov/">plant hardiness zone map</a>, which has long helped gardeners and growers figure out which plants are most likely to thrive in a given location. </p>
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<a href="https://images.theconversation.com/files/583488/original/file-20240321-28-3mclw8.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A U.S. map divided into colored geographic zones with a numbered key." src="https://images.theconversation.com/files/583488/original/file-20240321-28-3mclw8.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/583488/original/file-20240321-28-3mclw8.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/583488/original/file-20240321-28-3mclw8.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/583488/original/file-20240321-28-3mclw8.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/583488/original/file-20240321-28-3mclw8.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/583488/original/file-20240321-28-3mclw8.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/583488/original/file-20240321-28-3mclw8.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The 2023 USDA plant hardiness zone map shows the areas where plants can be expected to grow, based on extreme winter temperatures. Darker shades (purple to blue) denote colder zones, phasing southward into temperate (green) and warm zones (yellow and orange).</span>
<span class="attribution"><a class="source" href="https://planthardiness.ars.usda.gov/">USDA</a></span>
</figcaption>
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<p>Comparing the 2023 map to the previous version from 2012 clearly shows that as climate change warms the Earth, plant hardiness zones are shifting northward. On average, the coldest days of winter in our current climate, based on temperature records from 1991 through 2020, are 5 degrees Fahrenheit (2.8 Celsius) warmer than they were between 1976 and 2005. </p>
<p>In some areas, including the central Appalachians, northern New England and north central Idaho, winter temperatures have warmed by 1.5 hardiness zones – 15 degrees F (8.3 C) – over the same 30-year window. This warming changes the zones in which plants, whether annual or perennial, will ultimately succeed in a climate on the move.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/583491/original/file-20240321-24-nsmj8j.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="U.S. map showing large areas colored tan, denoting a 5-degree increase in average winter minimum temperatures." src="https://images.theconversation.com/files/583491/original/file-20240321-24-nsmj8j.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/583491/original/file-20240321-24-nsmj8j.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=464&fit=crop&dpr=1 600w, https://images.theconversation.com/files/583491/original/file-20240321-24-nsmj8j.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=464&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/583491/original/file-20240321-24-nsmj8j.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=464&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/583491/original/file-20240321-24-nsmj8j.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=583&fit=crop&dpr=1 754w, https://images.theconversation.com/files/583491/original/file-20240321-24-nsmj8j.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=583&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/583491/original/file-20240321-24-nsmj8j.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=583&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">This map shows how plant hardiness zones have shifted northward from the 2012 to the 2023 USDA maps. A half-zone change corresponds to a tan area. Areas in white indicate zones that experienced minimal change.</span>
<span class="attribution"><a class="source" href="https://site.extension.uga.edu/climate/2023/11/new-usda-plant-hardiness-zone-map-shows-most-of-southeast-has-gotten-one-half-zone-warmer/">Prism Climate Group, Oregon State University</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
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<p>As a <a href="https://scholar.google.com/citations?user=frEPl6IAAAAJ&hl=en">plant pathologist</a>, I have devoted my career to understanding and addressing plant health issues. Many stresses not only shorten the lives of plants, but also affect their growth and productivity. </p>
<p>I am also a gardener who has seen firsthand how warming temperatures, pests and disease affect my annual harvest. By understanding climate change impacts on plant communities, you can help your garden reach its full potential in a warming world.</p>
<h2>Hotter summers, warmer winters</h2>
<p>There’s no question that the temperature trend is upward. From 2014 through 2023, the world experienced the <a href="https://www.noaa.gov/news/world-just-sweltered-through-its-hottest-august-on-record">10 hottest summers ever recorded</a> in 174 years of climate data. Just a few months of sweltering, unrelenting heat can significantly affect plant health, especially <a href="https://extension.psu.edu/cool-season-vs-warm-season-vegetables">cool-season garden crops</a> like broccoli, carrots, radishes and kale. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/583468/original/file-20240321-26-b3sckt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Radishes sprouting in a garden bed." src="https://images.theconversation.com/files/583468/original/file-20240321-26-b3sckt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/583468/original/file-20240321-26-b3sckt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=302&fit=crop&dpr=1 600w, https://images.theconversation.com/files/583468/original/file-20240321-26-b3sckt.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=302&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/583468/original/file-20240321-26-b3sckt.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=302&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/583468/original/file-20240321-26-b3sckt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=380&fit=crop&dpr=1 754w, https://images.theconversation.com/files/583468/original/file-20240321-26-b3sckt.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=380&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/583468/original/file-20240321-26-b3sckt.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=380&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Radishes are cool-season garden crops that cannot withstand the hottest days of summer.</span>
<span class="attribution"><span class="source">Matt Kasson</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Winters are also warming, and this matters for plants. The USDA defines plant hardiness zones based on the coldest average annual temperature in winter at a given location. Each zone represents a 10-degree F range, with zones numbered from 1 (coldest) to 13 (warmest). Zones are divided into 5-degree F half zones, which are lettered “a” (northern) or “b” (southern). </p>
<p>For example, the coldest hardiness zone in the lower 48 states on <a href="https://planthardiness.ars.usda.gov/">the new map</a>, 3a, covers small pockets in the northernmost parts of Minnesota and has winter extreme temperatures of -40 F to -35 F. The warmest zone, 11b, is in Key West, Florida, where the coldest annual lows range from 45 F to 50 F. </p>
<p>On the <a href="https://planthardiness.ars.usda.gov/system/files/US_Map_2012.jpg">2012 map</a>, northern Minnesota had a much more extensive and continuous zone 3a. North Dakota also had areas designated in this same zone, but those regions now have shifted completely into Canada. Zone 10b once covered the southern tip of mainland Florida, including Miami and Fort Lauderdale, but has now been pushed northward by a rapidly encroaching zone 11a. </p>
<p>Many people buy seeds or seedlings without thinking about hardiness zones, planting dates or disease risks. But when plants have to contend with temperature shifts, heat stress and disease, they will eventually struggle to survive in areas where they once thrived. </p>
<p>Successful gardening is still possible, though. Here are some things to consider before you plant:</p>
<h2>Annuals versus perennials</h2>
<p>Hardiness zones matter far less for <a href="https://www.britannica.com/science/annual">annual plants</a>, which germinate, flower and die in a single growing season, than for <a href="https://www.britannica.com/science/perennial">perennial plants</a> that last for several years. Annuals typically avoid the lethal winter temperatures that define plant hardiness zones. </p>
<p>In fact, most annual seed packs don’t even list the plants’ hardiness zones. Instead, they provide sowing date guidelines by geographic region. It’s still important to follow those dates, which help ensure that frost-tender crops are not planted too early and that cool-season crops are not harvested too late in the year.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/583497/original/file-20240321-19-q24j99.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Orange flowers blooming with other plants and grasses." src="https://images.theconversation.com/files/583497/original/file-20240321-19-q24j99.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/583497/original/file-20240321-19-q24j99.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/583497/original/file-20240321-19-q24j99.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/583497/original/file-20240321-19-q24j99.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/583497/original/file-20240321-19-q24j99.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/583497/original/file-20240321-19-q24j99.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/583497/original/file-20240321-19-q24j99.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">California poppies are typically grown as annuals in cool areas, but can survive for several years in hardiness zones 8-10.</span>
<span class="attribution"><a class="source" href="https://flic.kr/p/FWtHc">The Marmot/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<h2>User-friendly perennials have broad hardiness zones</h2>
<p>Many perennials can grow across wide temperature ranges. For example, hardy fig and hardy kiwifruit grow well in zones 4-8, an area that includes most of the Northeast, Midwest and Plains states. Raspberries are hardy in zones 3-9, and blackberries are hardy in zones 5-9. This eliminates a lot of guesswork for most gardeners, since a majority of U.S. states are dominated by two or more of these zones. </p>
<p>Nevertheless, it’s important to pay attention to plant tags to avoid selecting a variety or cultivar with a restricted hardiness zone over another with greater flexibility. Also, pay attention to instructions about proper sun exposure and planting dates after the last frost in your area. </p>
<h2>Fruit trees are sensitive to temperature fluctuations</h2>
<p>Fruit trees have two parts, the rootstock and the scion wood, that are <a href="https://extension.unh.edu/sites/default/files/migrated_unmanaged_files/Resource003733_Rep5323.pdf">grafted together to form a single tree</a>. Rootstocks, which consist mainly of a root system, determine the tree’s size, timing of flowering and tolerance of soil-dwelling pests and pathogens. Scion wood, which supports the flowers and fruit, determines the fruit variety. </p>
<p>Most commercially available fruit trees can tolerate a wide range of hardiness zones. However, stone fruits like peaches, plums and cherries are more sensitive to temperature fluctuations within those zones – particularly abrupt swings in winter temperatures that create unpredictable freeze-thaw events. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/583498/original/file-20240321-18-w6ef0y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Packages for hardy fig and kiwi seedlings." src="https://images.theconversation.com/files/583498/original/file-20240321-18-w6ef0y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/583498/original/file-20240321-18-w6ef0y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=467&fit=crop&dpr=1 600w, https://images.theconversation.com/files/583498/original/file-20240321-18-w6ef0y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=467&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/583498/original/file-20240321-18-w6ef0y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=467&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/583498/original/file-20240321-18-w6ef0y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=587&fit=crop&dpr=1 754w, https://images.theconversation.com/files/583498/original/file-20240321-18-w6ef0y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=587&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/583498/original/file-20240321-18-w6ef0y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=587&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Following planting instructions carefully can maximize plants’ chances of success.</span>
<span class="attribution"><span class="source">Matt Kasson</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>These seesaw weather episodes affect all types of fruit trees, but stone fruits appear to be more susceptible, possibly because they flower earlier in spring, have fewer hardy rootstock options, or have bark characteristics that make them more vulnerable to winter injury. </p>
<p>Perennial plants’ hardiness increases through the seasons in a process called <a href="https://extension.umd.edu/resource/hardening-vegetable-seedlings-home-garden/">hardening off</a>, which conditions them for harsher temperatures, moisture loss in sun and wind, and full sun exposure. But a too-sudden autumn temperature drop can cause plants to die back in winter, an event known as <a href="https://extension.psu.edu/winterkill-of-turfgrasses">winter kill</a>. Similarly, a sudden spring temperature spike can lead to premature flowering and subsequent frost kill.</p>
<h2>Pests are moving north too</h2>
<p>Plants aren’t the only organisms constrained by temperature. With milder winters, southern insect pests and plant pathogens are expanding their ranges northward. </p>
<p>One example is <a href="https://www.britannica.com/science/blight">Southern blight</a>, a stem and root rot disease that affects 500 plant species and is caused by a fungus, <em>Agroathelia rolfsii</em>. It’s often thought of as affecting hot Southern gardens, but has become more commonplace recently in the Northeast U.S. on tomatoes, <a href="https://theconversation.com/how-to-keep-your-jack-o-lantern-from-turning-into-moldy-maggoty-mush-before-halloween-190526">pumpkins and squash</a>, and other crops, including <a href="https://extension.psu.edu/apple-disease-southern-blight">apples in Pennsylvania</a>. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/583501/original/file-20240321-26-h3tdv4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A stem dotted with small round growths." src="https://images.theconversation.com/files/583501/original/file-20240321-26-h3tdv4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/583501/original/file-20240321-26-h3tdv4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/583501/original/file-20240321-26-h3tdv4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/583501/original/file-20240321-26-h3tdv4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/583501/original/file-20240321-26-h3tdv4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/583501/original/file-20240321-26-h3tdv4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/583501/original/file-20240321-26-h3tdv4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Southern blight (small round fungal structures) at the base of a tomato plant.</span>
<span class="attribution"><a class="source" href="https://ag.purdue.edu/department/arge/swpap/southern-blight-tomato.html">Purdue University</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Other plant pathogens may take advantage of milder winter temperatures, which leads to prolonged saturation of soils instead of freezing. Both plants and microbes are less active when soil is frozen, but in wet soil, microbes have an opportunity to colonize dormant perennial plant roots, leading to more disease.</p>
<p>It can be challenging to accept that climate change is stressing some of your garden favorites, but there are thousands of varieties of plants to suit both your interests and your hardiness zone. Growing plants is an opportunity to <a href="https://theconversation.com/take-a-break-from-your-screen-and-look-at-plants-botanizing-is-a-great-way-to-engage-with-life-around-you-210616">admire their flexibility</a> and the features that enable many of them to thrive in a world of change.</p><img src="https://counter.theconversation.com/content/222108/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Matt Kasson receives funding from the US Department of Agriculture.</span></em></p>The US Department of Agriculture has updated its plant hardiness zone map, which shows where various plants will grow across the country. Gardeners should take note.Matt Kasson, Associate Professor of Mycology and Plant Pathology, West Virginia UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2254752024-03-13T06:19:20Z2024-03-13T06:19:20ZRedwood trees are growing almost as fast in the UK as their Californian cousins – new study<figure><img src="https://images.theconversation.com/files/581046/original/file-20240311-22-169fj.jpg?ixlib=rb-1.1.0&rect=11%2C23%2C3870%2C2560&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/sequoias-73346425">Galyna Andrushko/Shutterstock</a></span></figcaption></figure><p>What can <a href="https://plants.ces.ncsu.edu/plants/sequoiadendron-giganteum/">live for over 3,000 years</a>, weigh over 150 tonnes and could be sitting almost unnoticed in your <a href="https://www.woodlandtrust.org.uk/visiting-woods/woods/havering-county-park/">local park</a>? Giant sequoias (known as giant redwoods in the UK) are among the tallest and <a href="https://www.nps.gov/redw/planyourvisit/upload/ThreeTrees-2014-508.pdf">heaviest</a> organisms that have ever lived on Earth, not to mention they have the potential to <a href="https://www.nps.gov/parkhistory/online_books/shirley/sec11.htm#:%7E:text=Sierra%20Redwood%E2%80%94the%20world's%20oldest,oldest%20living%20things%20in%20existence">live longer</a> than other species.</p>
<p>My team’s <a href="https://royalsocietypublishing.org/doi/10.1098/rsos.230603">new study</a>
is the first to look at the growth of giant sequoias in the UK – and they seem to be doing remarkably well. Trees at two of the three sites we studied matched the <a href="https://arboretum.ucdavis.edu/sites/g/files/dgvnsk1546/files/inline-files/redwood_exhibits_0.pdf">average growth rates</a> of their counterparts in the US, where they come from. These remarkable trees are being planted in an effort to help absorb carbon, but perhaps more importantly they are becoming a striking and much-admired part of the UK landscape.</p>
<p>To live so long, giant sequoias have evolved to be extraordinarily resilient. In their <a href="https://www.visitsequoia.com/explore/spring-summer-fall-activities/redwoods-and-sequoias">native northern California</a>, they occupy an ecological niche in mountainous terrain 1400 – 2100 metres above sea level. </p>
<p>Their <a href="https://cdnsciencepub.com/doi/10.1139/x94-092">thick spongy bark</a> insulates against fire and disease and they can survive severe winters and arid summers. Despite these challenges these trees <a href="https://doi.org/10.1002/2016GB005546">absorb and store</a> CO₂ faster and in greater quantities than almost any other in the world, storing up to five times more carbon per hectare than even tropical rainforests. However, the changing climate means Californian giant sequoias <a href="https://www.nps.gov/articles/000/giant-sequoias-face-new-threats.htm">are under threat</a> from more frequent and extreme droughts and fires. More than 10% of the remaining population of around 80,000 wild trees were killed <a href="https://www.theguardian.com/us-news/2021/jun/02/sequoias-destroyed-california-castle-fire">in a single fire</a> in 2020 alone.</p>
<h2>Tree giants from the US</h2>
<p>What is much less well-known is that there are an estimated <a href="https://www.forestryengland.uk/news/over-half-million-natures-giants-the-nations-forests#:%7E:text=With%20now%20over%20half%20a,species'%20long%2Dterm%20survival.">half a million sequoias</a> (wild and planted) in England, dotted across the landscape. So how well are the UK giant sequoias doing? To try and answer this, my team used a technique called <a href="https://info.vercator.com/blog/3-types-of-terrestrial-laser-scanners">terrestrial laser scanning</a> to measure the size and volume of giant sequoias. </p>
<figure class="align-center ">
<img alt="Woman carrying baby stands next to base of giant trees" src="https://images.theconversation.com/files/581048/original/file-20240311-26-c1fdtm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/581048/original/file-20240311-26-c1fdtm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/581048/original/file-20240311-26-c1fdtm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/581048/original/file-20240311-26-c1fdtm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/581048/original/file-20240311-26-c1fdtm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/581048/original/file-20240311-26-c1fdtm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/581048/original/file-20240311-26-c1fdtm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Sequoia national park in California, USA.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/mother-infant-visit-sequoia-national-park-1175764084">My Good Images/Shutterstock</a></span>
</figcaption>
</figure>
<p>The laser sends out half a million pulses a second and if a pulse hits a tree, the 3D location of each “hit” is recorded precisely. This gives us a map of tree structure in unprecedented detail, which we can use to estimate volume and mass, effectively allowing us to estimate the tree’s weight. If we know how old the trees are, we can estimate how fast they are growing and accumulating carbon.</p>
<p>As part of a Master’s project with former student Ross Holland, and along with colleagues at Kew Royal Botanical Gardens, we measured giant sequoias across three sites - <a href="https://www.rbge.org.uk/visit/benmore-botanic-garden/">Benmore botanical gardens</a> in Scotland, <a href="https://www.kew.org/wakehurst">Kew Wakehurst</a> in Sussex and <a href="https://www.havering.gov.uk/info/20037/parks/723/havering_country_park">Havering Country Park</a> in Essex. These sites span the wettest (Benmore) and driest (Havering) climates in the UK, enabling us to assess how rainfall affects growth. </p>
<p>The fastest-growing trees we measured are growing almost as fast as they do in California, adding 70cm of height and storing 160kg of carbon per year, about twice that of a <a href="https://onetreeplanted.org/blogs/stories/how-much-co2-does-tree-absorb">native UK oak</a>. The trees at Benmore are already among the tallest trees in the UK at 55 metres, the current record-holder being a <a href="https://www.outdoorlook.co.uk/blog/post/record-breaking-tall-trees-in-the-uk">66 metre Douglas Fir</a> in Scotland. The redwoods, being faster growing, are likely to take that title in the next decade or two. And these trees are “only” around 170 years old. No native tree in the UK is taller than about 47 metres. We also found significant differences in growth rates across the UK. They grow fastest in the north where the climate is wetter.</p>
<p>So how did these trees get here? <a href="https://academic.oup.com/jhc/article/35/2/347/6651665">Exotic plant collecting</a> was big business in the 18th and 19th centuries, in large part as a display of wealth and taste. Giant sequoias were first introduced in 1853 by Scottish grain merchant and keen amateur collector <a href="https://www.giant-sequoia.com/gallery/scotland/">Patrick Matthew</a>, who gave them to friends. Later that same year commercial nurseryman <a href="https://www.nationaltrust.org.uk/discover/nature/trees-plants/how-the-giant-sequoia-came-to-england">William Lobb</a> brought many more from California, along with accounts of the giant trees from which they came. </p>
<p>Giant sequoias quickly became a sensation and were planted to create imposing avenues, at the entrances of grand houses and estates, in churchyards, parks and botanic gardens. The letters about these trees helps us to accurately age planted trees, enabling us to calculate their growth rates. </p>
<p>Normally, you need to take samples <a href="https://www.nature.scot/sites/default/files/2018-09/Publication%202018%20-%20SNH%20Research%20Report%20789%20-%20A%20review%20of%20the%20theory%20and%20practice%20of%20tree%20coring%20on%20live%20ancient%20and%20veteran%20trees.pdf">from a tree’s core</a> to get an accurate age estimate but that can damage the tree. </p>
<h2>Imagine their potential</h2>
<p>UK sequoias are unlikely to grow as tall as their Californian counterparts, which tend to grow in forests, due to lightning strikes and high winds – always a risk when you’re the tallest thing in the landscape rather than one among many. More recently, there has been a <a href="https://press.royalsociety.org/Uploads/RSOS230603_Proof.pdf">resurgence in planting</a> giant sequoias in the UK, particularly <a href="https://news.hackney.gov.uk/hackney-plants-70-trees-to-commemorate-70th-day-of-the-70th-year-of-the-queens-reign/#:%7E:text=Hackney%20has%20planted%2070%20sequoia,the%20borough's%20Platinum%20Jubilee%20celebrations.">in urban settings</a>. This is because of their carbon storage potential and perhaps because people seem to <a href="https://press.royalsociety.org/Uploads/RSOS230603_Proof.pdf">really like them</a>. </p>
<p>We urgently need to understand how UK trees will fare in the face of <a href="https://www.bbc.co.uk/news/science-environment-67845671">much hotter, drier summers</a>, <a href="https://theconversation.com/storm-ciaran-is-breaking-records-and-research-suggests-more-severe-weather-in-future-216842">stormier winters</a> and with <a href="https://nationalemergenciestrust.org.uk/wildfires-growing-risk/">increased risks of fire</a>. Global trade is also increasing <a href="https://www.nature.com/articles/s41579-021-00639-z#:%7E:text=The%20economic%20and%20environmental%20threats,in%20recent%20years96%2C97.">the spread of disease</a> among plantlife. More work is needed to consider the impact of planting non-native species like giant sequoias on native habitats and biodiversity but our work has shown that they are apparently very happy with our climate, so far. </p>
<p>More importantly, we have to remember that trees are more than just stores of carbon. If we value trees only as carbon sticks we will end up with thousands of hectares of monoculture, which isn’t good for nature. </p>
<p>But these giant sequoias are here to stay and are becoming a beautiful and resilient part of our landscape. </p>
<hr>
<figure class="align-right ">
<img alt="Imagine weekly climate newsletter" src="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
</figcaption>
</figure>
<p><strong><em>Don’t have time to read about climate change as much as you’d like?</em></strong>
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<p class="fine-print"><em><span>Mathias Disney receives funding from UKRI via NERC, the National Centre for Earth Observation (NCEO), European Space Agency, NASA and the Smithsonian Tropical Research Institute.</span></em></p>Their incredible resilience means they are becoming part of the UK landscape.Mathias Disney, Reader in Remote Sensing, Department of Geography, UCLLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2217202024-03-11T21:26:04Z2024-03-11T21:26:04ZAllergen warning: “Vegan” foods may contain milk and eggs<figure><img src="https://images.theconversation.com/files/570731/original/file-20240112-29-t9z77z.jpg?ixlib=rb-1.1.0&rect=4%2C0%2C989%2C667&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">When buying pre-packaged foods, consumers with allergies rely on the declarations in the list of ingredients to identify safe foods.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><p>The popularity of vegan diets continues to increase around the world. Indeed, in 2023, the vegan food market grew to <a href="https://www.expertmarketresearch.com/reports/vegan-food-market">more than US$27 billion</a>.</p>
<p>The term “vegan” usually refers to foods that contain no animal ingredients (meat, poultry, eggs, milk, fish, seafood).</p>
<p>While some consumers consider them to be healthier, vegan foods are also an interesting alternative for consumers concerned about the environment, sustainable development, and animal welfare.</p>
<p>But another type of consumer may be turning to these products for a completely different reason: people who are allergic to proteins of animal origin, such as cow’s milk and eggs.</p>
<p>In view of this, <a href="https://parera.ulaval.ca">our research group</a>, a leader in food allergen risk analysis in Canada, decided to explore <a href="https://link.springer.com/article/10.1186/s13223-023-00836-w">the following two questions</a>:</p>
<ul>
<li><p>Do consumers who are allergic to animal proteins consider vegan products to be safe?</p></li>
<li><p>And, if so, are these products truly safe for them?</p></li>
</ul>
<h2>What’s in it for consumers with allergies?</h2>
<p>The answers to these questions are crucial for people with food allergies who risk suffering potentially severe reactions (anaphylaxis) from consuming these products.</p>
<p>Food allergies affect around <a href="https://www.jaci-inpractice.org/article/S2213-2198(19)30912-2/fulltext">six per cent of Canadians</a>, including 0.8 per cent who are allergic to eggs, and 1.1 per cent to milk.</p>
<p>Despite the fact that different forms <a href="https://foodallergycanada.ca/living-with-allergies/allergy-treatments-and-therapies/treatments-and-therapies/">of immunotherapy or allergen desensitization</a> have shown promising results, the most effective strategy for avoiding allergic reactions is still to refrain from eating foods that may contain allergens.</p>
<p>When buying pre-packaged foods, consumers with allergies rely on declarations in the list of ingredients to identify foods that are safe for them. Regulatory authorities who are responsible for the quality and safety of food recognize the importance of accurate ingredients declarations for allergic consumers. Thus, it is <a href="https://www.canada.ca/en/health-canada/services/food-nutrition/food-labelling/allergen-labelling.html">mandatory</a> to list every allergen that has been voluntarily added to a pre-packaged food item.</p>
<p>However, when it comes to ingredients that may be unintentionally present — for example, as due to cross-contact during food processing — there is a regulatory gap. These ingredients are generally identified with the warning “may contain,” which is used (or sometimes <a href="https://www.sciencedirect.com/science/article/abs/pii/S2213219818300102">overused</a>) voluntarily and randomly by food processors.</p>
<p>Furthermore, the term “vegan” is neither standardized nor defined in Canadian regulations. In fact, <a href="https://inspection.canada.ca/food-labels/labelling/industry/composition-and-quality/eng/1625516122300/1625516122800?chap=2">the Canadian Food Inspection Agency</a> notes that, with regard to the use of the term “vegan,”</p>
<blockquote>
<p>…companies can apply additional criteria or standards that take account of other factors in addition to the ingredients of the food.</p>
</blockquote>
<p>However, details or examples of these elements are not provided. This lack of a precise regulatory definition prevents the implementation of compliance requirements.</p>
<p>Yet, most <a href="https://recalls-rappels.canada.ca/en/search/site?search_api_fulltext=vegan">recalls</a> of products marketed as “vegan” are due to the presence of undeclared ingredients of animal origin, in particular milk and eggs.</p>
<h2>What do consumers with food allergies say?</h2>
<p>In this context, and as part of a <a href="https://www.researchsquare.com/article/rs-2583779/v1">survey</a> of consumers with allergies conducted in collaboration with <a href="https://foodallergycanada.ca">Food Allergy Canada</a>, we asked participants who indicated that they were allergic (or were the parents of a child who was allergic) to eggs or milk if they bought products marketed as “vegan.”</p>
<p>Of the 337 respondents, 72 per cent said they sometimes included these products in their purchases, 14 per cent said they always did, and 14 per cent never.</p>
<p>These <a href="https://link.springer.com/article/10.1186/s13223-023-00836-w">results</a> suggest that these consumers do, indeed, consider the claim “vegan” as an indicator of the absence of animal proteins — an absence which, again, is not supported by any regulatory requirement or definition.</p>
<p>Since the absence of these ingredients is not guaranteed, these consumption habits could put people who are allergic to eggs and/or milk at risk.</p>
<p>An education campaign to clarify that the term “vegan” is an indicator of dietary <em>preferences</em> and not <em>risks</em> would therefore be important for this community.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/569134/original/file-20240112-29-5nq5bg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="dark chocolate" src="https://images.theconversation.com/files/569134/original/file-20240112-29-5nq5bg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/569134/original/file-20240112-29-5nq5bg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=372&fit=crop&dpr=1 600w, https://images.theconversation.com/files/569134/original/file-20240112-29-5nq5bg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=372&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/569134/original/file-20240112-29-5nq5bg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=372&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/569134/original/file-20240112-29-5nq5bg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=467&fit=crop&dpr=1 754w, https://images.theconversation.com/files/569134/original/file-20240112-29-5nq5bg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=467&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/569134/original/file-20240112-29-5nq5bg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=467&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Some dark chocolate bars marketed as ‘certified vegan’ contain milk proteins.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<h2>Do vegan products contain ingredients of animal origin?</h2>
<p>The fact that 86 per cent of survey respondents buy “vegan” products suggests that the incidence of allergic reactions linked to these foods is potentially rare.</p>
<p>We therefore <a href="https://link.springer.com/article/10.1186/s13223-023-00836-w">analyzed</a> the egg and milk protein content of “vegan” and “plant-based” products marketed in Québec.</p>
<p>A total of 124 products were analyzed for the presence of egg (64) and/or milk (87) proteins.</p>
<p>Egg protein was not detected in any samples, but five samples contained milk proteins: these included four dark chocolate bars marketed as “certified vegan” and a supermarket brand chestnut cake.</p>
<p>These five products declared the potential presence of milk with a warning, “may contain milk.”</p>
<p>We used the concentrations of milk proteins quantified in these products, combined with the quantities of the food that would be consumed in a single eating occasion, to calculate an exposure dose, in milligrams of allergen protein. We then estimated the probability of these doses provoking a reaction in the allergic populations concerned by using <a href="https://www.sciencedirect.com/science/article/pii/S0278691520307213">correlation models</a>. Our results show that the calculated doses could trigger reactions in six per cent of milk-allergic consumers, for the chocolate bars, and one per cent, for the cake.</p>
<h2>How can consumers with food allergies protect themselves?</h2>
<p>Although this level of risk may be perceived as low, it is likely to vary without notice. And this will remain the case until regulatory requirements are put in place.</p>
<p>In fact, rather than attributing it to the presence of a “vegan” or “plant-based” claim, this level of risk most likely reflects <a href="https://www.cell.com/heliyon/pdf/S2405-8440(22)02590-7.pdf">good allergen management practices</a>, characteristic of the North American food manufacturing sector.</p>
<p>Thus, even if a statement “may contain milk” seems contradictory in a “vegan” or “plant-based” product, people allergic to milk should interpret it as an indication that this product may pose a risk to their health.</p><img src="https://counter.theconversation.com/content/221720/count.gif" alt="La Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Samuel Godefroy's research activities are funded by the Natural Sciences and Engineering Research Council of Canada, the Foreign Agriculture Service of the United States Department of Agriculture, R-Biopharm GmbH and R-Biopharm Canada Inc. He acts as an expert advisor to members of the food and beverage industry, international organizations (the Food and Agriculture Organization of the United Nations, the United Nations Industrial Development Organization and the World Bank), international food regulatory bodies such as the China National Centre for Food Safety Risk Assessment and consumer organizations such as Food Allergy Canada. Godefroy is Chairman of the Board of the Global Food Regulatory Science Society (GFoRSS).</span></em></p><p class="fine-print"><em><span>Jérémie Théolier et Silvia Dominguez ne travaillent pas, ne conseillent pas, ne possèdent pas de parts, ne reçoivent pas de fonds d'une organisation qui pourrait tirer profit de cet article, et n'ont déclaré aucune autre affiliation que leur poste universitaire.</span></em></p>Vegan foods are considered by most consumers to have no ingredients of animal origin, but they may actually contain milk proteins.Silvia Dominguez, Professionnelle de recherche en sciences des aliments, Université LavalJérémie Théolier, Professionel de recherche en sciences des aliments, Université LavalSamuel Godefroy, Professeur titulaire - Sciences des aliments, Université LavalLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2229722024-03-11T12:25:42Z2024-03-11T12:25:42ZWhy do trees need sunlight? An environmental scientist explains photosynthesis<figure><img src="https://images.theconversation.com/files/578432/original/file-20240227-20-s7p24d.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C2048%2C1364&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The reason trees need sunlight is the same reason their leaves are green.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/scottb211/10108377914/"> Scottb211/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=293&fit=crop&dpr=1 600w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=293&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=293&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=368&fit=crop&dpr=1 754w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=368&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=368&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
</figcaption>
</figure>
<p><em><a href="https://theconversation.com/us/topics/curious-kids-us-74795">Curious Kids</a> is a series for children of all ages. If you have a question you’d like an expert to answer, send it to <a href="mailto:curiouskidsus@theconversation.com">curiouskidsus@theconversation.com</a>.</em></p>
<hr>
<blockquote>
<p><strong>Why do trees need sunlight? – Tillman, age 9, Asheville, North Carolina</strong></p>
</blockquote>
<hr>
<p>Trees need sunlight for the same reason you need food. The energy from the Sun’s rays is a crucial ingredient in how plants make their own food that helps them power all their cells. Since trees don’t harvest or hunt food, they have to produce their own. The way they make their food is a unique and important chemical process called photosynthesis.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/574698/original/file-20240209-30-3fr5f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="honey-comb pattern of rings each containing many small green spheres" src="https://images.theconversation.com/files/574698/original/file-20240209-30-3fr5f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/574698/original/file-20240209-30-3fr5f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=406&fit=crop&dpr=1 600w, https://images.theconversation.com/files/574698/original/file-20240209-30-3fr5f.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=406&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/574698/original/file-20240209-30-3fr5f.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=406&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/574698/original/file-20240209-30-3fr5f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=510&fit=crop&dpr=1 754w, https://images.theconversation.com/files/574698/original/file-20240209-30-3fr5f.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=510&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/574698/original/file-20240209-30-3fr5f.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=510&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Chlorophyll is what makes leaves green.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Plagiomnium_affine_laminazellen.jpeg">Kristian Peters-Fabelfroh/Wikimedia</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<h2>What is photosynthesis?</h2>
<p>The cells in plants and all other living things have microscopic components called <a href="https://www.genome.gov/genetics-glossary/Organelle">organelles</a>. One type of organelle in plant cells is the chloroplast, and it contains the <a href="https://www.kidzone.ws/science/lessons/pigments.html">pigment</a> chlorophyll, which is what makes leaves green. When chlorophyll receives sunlight, it starts the <a href="https://education.nationalgeographic.org/resource/photosynthesis">photosynthesis</a> reaction.</p>
<p>The name photosynthesis comes from the ancient Greek words “photo,” which means light, and “synthesis,” which means to make. During this food-making process, plants take carbon dioxide from the air and water from the ground, and with the energy from sunlight, make glucose. Glucose is a very simple type of sugar. Because it is a simple compound, it is simple to make.</p>
<p>Most of the time, photosynthesis occurs in leaves, and leaves take in sunlight to make food. There are some special plants, though, that actually absorb sunlight on their stems. Some of these include cactuses like the balloon-shaped <a href="https://www.gardenia.net/plant/echinocactus-grusonii-golden-barrel-cactus">golden barrel cactus</a>, the spiky <a href="https://huntington.org/educators/learning-resources/spotlight/cylindropuntia-munzii">Munz’s Cholla</a> and the paddle-shaped <a href="https://huntington.org/educators/learning-resources/spotlight/opuntia-ficus-indica">prickly pear</a>. Some plants even have roots that can photosynthesize, like the rare palm <em><a href="https://huntington.org/educators/learning-resources/spotlight/cryosophila-albida">Cryosophila albida</a></em>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/579708/original/file-20240304-28-wxa438.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A graphic diagram of a plant showing sun, soil, roots, leaves and a flower" src="https://images.theconversation.com/files/579708/original/file-20240304-28-wxa438.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/579708/original/file-20240304-28-wxa438.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=601&fit=crop&dpr=1 600w, https://images.theconversation.com/files/579708/original/file-20240304-28-wxa438.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=601&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/579708/original/file-20240304-28-wxa438.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=601&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/579708/original/file-20240304-28-wxa438.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=755&fit=crop&dpr=1 754w, https://images.theconversation.com/files/579708/original/file-20240304-28-wxa438.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=755&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/579708/original/file-20240304-28-wxa438.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=755&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Sunlight gives plants the energy to turn water and carbon dioxide into carbohydrates – the food their cells need to live and grow.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Photosynthesis_en.svg">At09kg/Wikimedia</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<h2>Photosynthesis is billions of years old</h2>
<p>Photosynthesis evolved more than <a href="https://doi.org/10.1104%2Fpp.110.161687">3.5 billion years ago</a>. Initially, only single-celled organisms, kind of like today’s algae, could make sugar this way. Oxygen is a waste product from the photosynthesis process, and over time, these single-celled organisms released enough oxygen to change the Earth’s atmosphere. Ultimately, we and all other animals needed this to happen to be able to live and breathe. </p>
<p>Over time, aquatic plants developed, and gradually plants <a href="https://doi.org/10.1126/science.aat3642">moved to land</a> around 500 million years ago to better access their most vital resource: sunlight. Plants eventually got taller by around <a href="https://doi.org/10.1126/science.aar2986">350 million years ago</a>. This is when the first tree evolved, which grew up to 150 feet tall. These trees looked like the evergreen trees we see today – sort of like pines, firs and spruce. And about 125 million years ago, trees that looked like the maples, oaks and beech trees we see today shared the landscape when <a href="https://new.nsf.gov/news/dinosaur-age-fossils-provide-new-insights-origin">dinosaurs ruled the Earth</a>.</p>
<h2>Not just good for plants</h2>
<p>The Sun provides energy for the Earth. However, we humans are not capable of taking in the sun directly and using it to power our bodies. So how do we make use of the Sun’s energy? Plants do it for us.</p>
<p>Plants take in that energy and make food for us and other animals to eat and oxygen for us to breathe. We wouldn’t exist without plants and photosynthesis.</p>
<p>Like the ancient tiny single-celled organisms from 3.5 billion years ago, some microorganisms today use photosynthesis. Specifically, the algae that you might see living on top of lakes and the ocean do. Chlorophyll is why algae is green. </p>
<p>There are <a href="https://news.asu.edu/20191114-asu-study-shows-some-aquatic-plants-depend-landscape-photosynthesis">aquatic plants</a> that use sunlight to grow. They typically make use of less sunlight because sunlight does not travel well through water.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/578425/original/file-20240227-30-2rnnkd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="yellowish green grass-like plants underwater" src="https://images.theconversation.com/files/578425/original/file-20240227-30-2rnnkd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/578425/original/file-20240227-30-2rnnkd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/578425/original/file-20240227-30-2rnnkd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/578425/original/file-20240227-30-2rnnkd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/578425/original/file-20240227-30-2rnnkd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/578425/original/file-20240227-30-2rnnkd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/578425/original/file-20240227-30-2rnnkd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Some plants can do photosynthesis underwater, where there is less sunlight.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/chesbayprogram/32446887586/">Chesapeake Bay Program/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span>
</figcaption>
</figure>
<p>In addition, there are a very few animals that can photosynthesize. The <a href="https://doi.org/10.1038/nature.2012.11214">pea aphid</a> uses pigment to harvest sunlight to make energy. The <a href="https://phys.org/news/2011-01-physicists-outer-shell-hornet-harvest.html">Oriental hornet</a> uses a pigment in its exoskeleton to make energy from sunlight. The <a href="https://www.nationalgeographic.com/animals/article/solar-powered-photosynthetic-sea-slugs-in-decline-news">emerald-green sea slug</a> eats algae and then incorporates chlorophyll from the algae into its body to photosynthesize. Because of this strategy, the sea slug can go nine months without eating. </p>
<p>So the answer to this question – why do trees need sunlight – is to make their food. And thanks to trees and other plants turning sunlight into their food, most of the rest of the living things on Earth get to eat, too!</p>
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<p><em>Hello, curious kids! Do you have a question you’d like an expert to answer? Ask an adult to send your question to <a href="mailto:curiouskidsus@theconversation.com">CuriousKidsUS@theconversation.com</a>. Please tell us your name, age and the city where you live.</em></p>
<p><em>And since curiosity has no age limit – adults, let us know what you’re wondering, too. We won’t be able to answer every question, but we will do our best.</em></p><img src="https://counter.theconversation.com/content/222972/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Rebekah Stein does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Trees – and all plants – harvest sunlight to gain the energy they need to live and grow.Rebekah Stein, Assistant Professor of Environmental Science, Quinnipiac UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2241652024-03-05T13:13:59Z2024-03-05T13:13:59ZThese tiny worm-like creatures in the soil can destroy pests but they can also kill crops - an expert’s guide to nematodes<figure><img src="https://images.theconversation.com/files/578226/original/file-20240227-16-a0262c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">PeopleImages/Getty Images</span></span></figcaption></figure><p>Whether you’re a gardener growing food for your household, a small scale farmer or a commercial producer, soil matters. You cannot really tell the difference between healthy and unhealthy soil just by looking at it. But there are organisms in the soil – creatures you can’t see with your naked eye – which scientists use to measure soil health. </p>
<p><a href="https://www.britannica.com/animal/nematode">Nematodes</a> are among the creatures that scientists look for. These multicellular, <a href="https://theconversation.com/all-you-need-to-know-about-the-space-travelling-nematode-a-worm-like-no-other-47949">wormlike animals</a> differ from most other organisms in the soil, such as bacteria and fungi, which are single celled. Nematodes are equipped with a digestive system. They’re also transparent, making it easy for scientists to examine their feeding habits.</p>
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Read more:
<a href="https://theconversation.com/all-you-need-to-know-about-the-space-travelling-nematode-a-worm-like-no-other-47949">All you need to know about the space travelling nematode: a worm like no other</a>
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<p>I study nematodes to use as biological control agents and also represent Stellenbosch University, South Africa, in the <a href="https://nemedussa.ugent.be">NEMEDUSSA project</a>. This is a consortium of 16 research and educational institutes across Africa and Europe who work on and study nematodes. We want to increase awareness, research and teaching about nematodes, especially in agricultural disciplines.</p>
<p>We also believe it’s important for everyone, especially those working in the <a href="https://extension.umn.edu/soybean-pest-management/soybean-cyst-nematode-management-guide">agricultural sector</a>, and even just casual food gardeners, to know about nematodes. If you grow tomatoes in your garden, for instance, <a href="https://doi.org/10.1155/2021/8820211">root-knot nematodes</a> can cause total crop failure.</p>
<p>Four main types of nematodes occur in soil. Each group has expert scientists studying their behaviour and how they can be managed in agricultural practice to minimise the amount of damage they cause. </p>
<h2>Free-living nematodes</h2>
<p>Free-living nematodes are non-parasites. They tend to feed on almost anything in the soil, including fungi, bacteria and other nematodes. In fact, without these free-living nematodes, soil is regarded as <a href="https://doi.org/10.1016/j.apsoil.2018.08.008">biologically dead</a> and unhealthy for plant growth. </p>
<h2>Plant-parasitic nematodes</h2>
<p>The unchecked build-up of plant-parasitic nematodes in unbalanced soil is every farmer’s nightmare. Such nematodes feed through a needle-like stylet, which they use as a syringe for obtaining food from the roots of plants. They have adapted their lifestyle from feeding on the outside of the root to inside it, where they are protected against the harsh soil environment.</p>
<p>Plant-parasitic nematodes can never be fully controlled. However, researchers have developed ways to keep them from multiplying to damaging levels. These techniques include planting crops that are resistant to specific nematodes or rotating with crops that the nematodes do not like.</p>
<h2>Entomopathogenic nematodes</h2>
<p>Entomopathogenic nematodes as biological control agents are <a href="https://www.researchgate.net/profile/Antoinette-Malan">my special interest</a>. They are plant allies. They feed on pest insects such as larvae and pupae that are in contact with the soil, rather than on plants. Researchers recommend that every farmer or food gardener should have entomopathogenic nematodes present in their soil because they help to keep insect numbers low. Yes, you can buy them: they’re <a href="https://www.e-nema.de/en/about-us/">available commercially</a>, including from <a href="https://biobee.co.za/solutions/biosf/">some South African companies</a>.</p>
<h2>Slug-parasitic nematodes</h2>
<p>Many slug species are in close contact with soil, so certain nematodes have adapted their feeding habits over millions of years to feed on slugs, as well as <a href="https://link.springer.com/chapter/10.1007/978-3-319-44210-5_23">some snails</a>.</p>
<p>Researchers realised that the slug nematode could be used as a biological control agent. Biocontrol involves using living organisms like pathogens or insects to control pests, rather than using more environmentally damaging chemical products. A commercial product, available under the trade name <a href="https://www.youtube.com/watch?v=JopdT8cmrh0">Nemaslug</a>®, was created in 1994 which harnessed the slug nematodes’ feeding habits for biocontrol. But it’s only available in Europe: research is ongoing to identify whether the nematode species used in the commercial product is found in South Africa and whether it’s non-toxic to local endangered molluscs.</p>
<h2>Monitor soil health</h2>
<p>My advice to gardeners and farmers, even those working at a small scale, is to regularly send soil samples for laboratory testing. This will allow you to find out what sorts of nematodes are living among your tomato plants – the “good guys” who take care of pests, or the plant parasites. There are a number of private companies (<a href="https://www.nemlab.co.za">Nemlab</a> is one example) in South Africa to do these sorts of analyses and offer advice based on the results.</p><img src="https://counter.theconversation.com/content/224165/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Antoinette Paula Malan receives funding from NEMEDUSA, Erasmus+ NEMEDUSSA project, Capacity Building in Higher Education (CBHE): Nematology Education in Sub-Sahara Africa (NEMEDUSSA). The project is funded by the European Union.</span></em></p>Four types of nematodes occur in soil.Antoinette Paula Malan, Researcher in Nematology, Parasitology, Systematics, Stellenbosch UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2242082024-03-04T17:03:18Z2024-03-04T17:03:18ZPotato charms: people throughout history have kept and even stolen wrinkly old vegetables for their health<p>In 1897, one Mr Burgess, the Clerk of Works at Oxford University, donated two shrivelled <a href="https://www.prm.ox.ac.uk/collections-online#/item/prm-object-62254">potatoes</a> to the Pitt Rivers Museum. He usually kept them in his pockets. They were the ultimate “jacket” potatoes.</p>
<p><a href="https://www.prm.ox.ac.uk/">The Pitt Rivers Museum</a> in Oxford is dedicated to categorising and displaying a “democracy of objects” not according to time or nation, but according to human usage. Since the potato is fairly ubiquitous in human culture, it means there are many in the museum’s collection. </p>
<p>In addition to Burgess’s donation, 11 other wrinkled specimens are catalogued in the museum’s collections, and are neatly labelled. The names of the previous owners are usually not identified because most of the potatoes were stolen before they were donated.</p>
<p>But why would someone would want to steal a wrinkly potato? The answer is these were not just any purloined spuds. They were medical charms thought to be cures for <a href="https://www.cdc.gov/arthritis/communications/features/rheumatic-diseases-and-pain.html">rheumatism</a> – and if they were <a href="https://insidestory.org.au/john-curtins-potato/">stolen</a>, they were thought to be even more effective.</p>
<p>In the Victorian era, and for centuries before, a variety of vegetables were carried whole, or pulverised and put into bags to hang around the neck in the hopes of warding off or curing illness.</p>
<h2>Plants as drugs</h2>
<p>Before modern pharmaceuticals, most <em>materia medica</em> (substances used in medical practice, or drugs) were herbal. Their usage was described in books by the ancient Greek physician <a href="https://www.loc.gov/item/2021666851">Pedanius Dioscorides</a> (40-70 AD) and in Pliny’s <a href="https://www.perseus.tufts.edu/hopper/text?doc=Perseus:text:1999.02.0137">Natural History</a> (1st century AD), an encyclopaedia written in ancient Rome. These books from the ancient world continued to be reference guides throughout the Renaissance.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/578278/original/file-20240227-28-ydbjo9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="An illustration of a mandrake root as a man." src="https://images.theconversation.com/files/578278/original/file-20240227-28-ydbjo9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/578278/original/file-20240227-28-ydbjo9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=815&fit=crop&dpr=1 600w, https://images.theconversation.com/files/578278/original/file-20240227-28-ydbjo9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=815&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/578278/original/file-20240227-28-ydbjo9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=815&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/578278/original/file-20240227-28-ydbjo9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1024&fit=crop&dpr=1 754w, https://images.theconversation.com/files/578278/original/file-20240227-28-ydbjo9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1024&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/578278/original/file-20240227-28-ydbjo9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1024&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Illustration of a mandrake plant depicting a naked man as the plant’s root. His ankles are tied together and he’s being pulled from the ground by a dog as a nearby man covers his ears to not hear the plant’s cries.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Mandrake_LJS_46_16r.jpg">Wikimedia</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span>
</figcaption>
</figure>
<p>In his book Pliny described the usefulness of plants such as the <a href="http://data.perseus.org/citations/urn:cts:latinLit:phi0978.phi001.perseus-eng1:22.9">mandrake root</a>, which was thought to resemble a human figure complete with what was known as “the virile members”. The root was made into amulets to be worn to promote fertility and in love magic. Using it in this way, is also referred to in the <a href="https://www.bible.com/bible/114/SNG.7.13.NKJV">Song of Solomon</a> in the Bible.</p>
<p>Because the root contained hallucinogenic and narcotic <a href="https://www.fs.usda.gov/wildflowers/ethnobotany/Mind_and_Spirit/mandrake.shtml">active ingredients</a>, it was also used as an anaesthetic and to relieve the pain of arthritis. By the 16th century, herbalist John Gerard’s <a href="https://www.biodiversitylibrary.org/page/35441266">Herball or General Historie of Plants</a> related the legend that if one pulled it from the ground, the root would scream, killing anyone who heard it (possibly a result of a couple of bad trips). </p>
<h2>Illnesses caused by the planets</h2>
<p><a href="https://www.newadvent.org/cathen/11468a.htm">Paracelsus</a>, a 16th-century Swiss doctor, elaborated upon such theories, claiming each plant had what was called a “signature” or sign of its medical application resembling the part of the body or ailment that it could cure. </p>
<p>For instance, lentils and rapeseed were thought sympathetically to cure smallpox because the seeds were similar to the pox pustules. The appropriate herbs, pulses, seeds or vegetables were bundled and worn about the neck to affect the cure.</p>
<p>Other plants, such as the <a href="https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&cad=rja&uact=8&ved=2ahUKEwj6mJ7TncuEAxXgTEEAHUBACaIQFnoECA0QAw&url=https%3A%2F%2Fplants.usda.gov%2FDocumentLibrary%2Fplantguide%2Fpdf%2Fpg_hean3.pdf&usg=AOvVaw1XcdaWN6EofZ3hX8kgJwAt&opi=89978449">sunflower</a>, were thought to promote the hot and dry characteristics of the sun, good to warm you if you suffered from a cold. </p>
<p>Plant therapy was also linked to the use of <a href="https://books.google.co.uk/books?id=40VHAQAAMAAJ&newbks=1&newbks_redir=0&dq=astrological%20botany&pg=PP5#v=onepage&q&f=false">astrology</a> in early medicine. The planets were thought to control the <a href="https://onlineexhibits.library.yale.edu/s/medicalastrology/page/the-medical-astrologer-s-toolkit">fluids or “humors”</a> in the body (black bile, blood, yellow bile, and phlegm), all of which had to be kept in careful balance to promote health. An imbalance was believed to be cured by bleeding or by the ingestion of an herbal remedy, or in some cases, wearing of the appropriate plant amulet.</p>
<p>Diseases caused by a particular planet could be healed by a herb of the opposing planet. For example, <a href="https://doi.org/10.1353/bhm.2000.0129">lunar diseases</a> were considered to produce an abundance of cold and moist humours, as the Moon controlled the waters in the tides. </p>
<p>Diseases that produced phlegm and caused sneezing like the common cold, or those that produced fluid-filled tumours, such as <a href="https://www.webmd.com/a-to-z-guides/what-is-scrofula">scrofula</a>, were therefore considered governed by the Moon. These lunar diseases could be cured by means of solar herbs or tinctures, which were hot and drying as sunbeams. Hence the sunflower cure. Lettuce which was watery was to be avoided.</p>
<p>But what of our potato and its connection to rheumatism? </p>
<p>There is a poison, called <a href="https://medlineplus.gov/ency/article/002875.htm">solanine</a>, present in green potatoes and potato eyes (the root-like sprouts). Solanine is chemically closely related to another poison <a href="https://www.mdpi.com/1420-3049/24/4/796">tropane alkaloid</a>, named atropine in deadly nightshade. In fact, the potato is called a <a href="https://www.webmd.com/diet/what-to-know-about-nightshade-vegetables">nightshade vegetable</a>.</p>
<p><a href="https://books.google.co.uk/books?id=o4uUxicORJoC&newbks=1&newbks_redir=0&dq=Roberts%20Bartholow%2C%20A%20Manual%20of%20Hypodermic%20Medication%2C%205th%20edition%201891%20(Philadelphia%20and%20London%3A%20J.B.%20Lippincott%2C%201891)%2C&pg=PA342#v=onepage&q&f=false">Atropine cream</a> in the Victorian era, sometimes in combination with morphine, was applied to “relieve the pain of rheumatism, sciatica and neuralgia”. Although there proved to be <a href="https://books.google.co.uk/books?id=JAzKSP4NagQC&lpg=PP1&pg=PA52#v">no scientific basis</a> for this, atropine is used in contemporary medicine to <a href="https://www.mayoclinic.org/drugs-supplements/atropine-sulfate-ophthalmic-route/side-effects/drg-20313091?p=1">dilate the pupils</a> or to <a href="https://www.ncbi.nlm.nih.gov/books/NBK470551/">elevate heartbeats</a> in a medical emergency.</p>
<p>There were several cases of murder involving putting higher levels of <a href="https://books.google.co.uk/books?id=JAzKSP4NagQC&lpg=PP1&pg=PA59#v=onepage&q=atropine&f=false">atropine in tea</a> or in a <a href="https://books.google.co.uk/books?id=JAzKSP4NagQC&lpg=PP1&pg=PA64#v=onepage&q=atropine&f=false">gin and tonic</a>, its bitter taste disguised by the booze. </p>
<p>As to why the potatoes had to be stolen to cure rheumatism, we still don’t quite know but it certainly adds to their charm. </p>
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<figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/536131/original/file-20230706-17-460x2d.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/536131/original/file-20230706-17-460x2d.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/536131/original/file-20230706-17-460x2d.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/536131/original/file-20230706-17-460x2d.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/536131/original/file-20230706-17-460x2d.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/536131/original/file-20230706-17-460x2d.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/536131/original/file-20230706-17-460x2d.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<p><em>Looking for something good? Cut through the noise with a carefully curated selection of the latest releases, live events and exhibitions, straight to your inbox every fortnight, on Fridays. <a href="https://theconversation.com/uk/newsletters/something-good-156">Sign up here</a>.</em></p>
<hr><img src="https://counter.theconversation.com/content/224208/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Anna Marie Roos receives funding from the National Science Foundation, the Andrew Mellon Foundation, the Arts and Humanities Research Council, the British Academy, the Royal Society of London, the Wellcome Trust, the McKnight Foundation, the Society of Authors, the Lincoln Record Society, and The Marc Fitch Fund</span></em></p>Screaming mandrakes, purloined potatoes and heat-giving sunflower seeds were thought to have healing properties.Anna Marie Roos, Professor of the History of Science and Medicine in the School of History and Heritage, University of LincolnLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2239302024-02-29T17:37:28Z2024-02-29T17:37:28ZPlants are flowering earlier than ever – here’s how they sense the seasons<p>Hedgerows in mid-February might have traditionally appeared white with snow; this year the white was the work of blackthorn blossoms – a harbinger of spring. Although a welcome sign after a wet and gloomy winter, the early flowering brings unease for experienced season watchers. Has this plant always flowered in mid-February, I wondered, or is something changing?</p>
<p>Fortunately, the science of recording and understanding seasonal events, phenology, has a long history in Britain. <a href="https://www.robertmarsham.co.uk/">Robert Marsham</a>, an 18th-century naturalist, kept records of the appearance of the flowers, birds and insects in his Norfolk village as far back as 1736. Marsham’s descendants continued the recording until 1958. The Woodland Trust maintains the tradition with <a href="https://naturescalendar.woodlandtrust.org.uk/">Nature’s Calendar</a>, a scheme in which members of the public are invited to record various seasonal events.</p>
<p><a href="https://royalsocietypublishing.org/doi/10.1098/rspb.2021.2456">Detailed analysis</a> of almost half a million plant records by scientists in 2022 showed that when all species were considered together the average flowering time in the UK had advanced by a month over the last 40 years. There was variation between species. Hawthorn, the common hedgerow plant, is generally flowering 13 days earlier than it did in the early 1980s while the flowers of the horse chestnut tree appear ten days earlier.</p>
<p>The climate has warmed rapidly since the 1980s. By flowering earlier, plants recognise that winters are becoming shorter and milder. They sense the days getting warmer and alter their spring development in a manner akin to humans feeling warmth on their skin and so stepping out with fewer layers of clothing. The precise mechanisms for detecting these cues differ between plants and animals, but both are responding to the climate as it changes. </p>
<h2>Detecting light and heat without eyes and skin</h2>
<p>Plants detect the shortening days of autumn with a pigment called phytochrome that is particularly sensitive to wavelengths in the red region of the electromagnetic spectrum. The longer autumn nights alter the quality of this red light. While this subtle shift escapes humans (our eyes are not sensitive to this part of the spectrum) a plant can detect this transition and start to change.</p>
<figure class="align-center ">
<img alt="A bench next to a woodland at sunset." src="https://images.theconversation.com/files/578640/original/file-20240228-18-qoad8t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/578640/original/file-20240228-18-qoad8t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=375&fit=crop&dpr=1 600w, https://images.theconversation.com/files/578640/original/file-20240228-18-qoad8t.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=375&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/578640/original/file-20240228-18-qoad8t.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=375&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/578640/original/file-20240228-18-qoad8t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=471&fit=crop&dpr=1 754w, https://images.theconversation.com/files/578640/original/file-20240228-18-qoad8t.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=471&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/578640/original/file-20240228-18-qoad8t.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=471&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Plants detect subtle changes in red light and instigate dormancy as autumn descends.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/romantic-autumn-mood-sunset-lake-ammersee-690569119">Art180/Shutterstock</a></span>
</figcaption>
</figure>
<p>Just as the autumn can engineer a drop in the level of the hormone serotonin in our blood, a plant that has sensed winter’s approach will increase the production of a hormone called abscisic acid. This has multiple effects. In deciduous trees, twigs stop growing and develop tough winter buds capable of surviving frost and snow and leaves fall off.</p>
<p>Growth in spring is determined by similar triggers of light length and temperature, but temperature typically has the more significant role. If plants only paid attention to light, they’d run the risk of starting growth when fatal frosts are still a threat or of missing good growing time in mild early spring days. Temperature detection determines when spring flowers appear. This is why global heating is evident in the earlier appearance of these flowers.</p>
<hr>
<p><em>Do the seasons feel increasingly weird to you? You’re not alone. Climate change is distorting nature’s calendar, causing plants to flower early and animals to emerge at the wrong time.</em></p>
<p><em>This article is part of a series, <a href="https://theconversation.com/uk/topics/wild-seasons-152175?utm_source=InArticleTop&utm_medium=TCUK&utm_campaign=WS">Wild Seasons</a>, on how the seasons are changing – and what they may eventually look like.</em></p>
<hr>
<p>It isn’t fully understood how plants detect temperature. Some of it may be due to a growth-stalling hormone in its cells breaking down when the air falls below a certain temperature, which in turn allows a growth hormone to increase. </p>
<p>While humans have nerves in their skin to detect temperature, plants probably rely on pigments, though the mechanism isn’t fully understood. Heat is part of the same electromagnetic spectrum that phytochrome is sensitive to, so possibly this pigment is involved. Whatever mechanisms are responsible for initiating growth, temperature also determines how fast plants grow.</p>
<h2>Flowers and pollinators out of sync</h2>
<p>Insect pollinators like bees must synchronise their life cycles so that they are on the wing when the blossoms on which they feed emerge. The timing of their emergence from winter is also determined by the effects of temperature and day length and mediated by hormones. </p>
<p>Evolution working on many generations of pollinators has generated a tight link between the emergence of flowers and that of their pollinators. If the appearance of flowers and pollinators isn’t synchronised, the insects have no nectar and the plants aren’t fertilised. </p>
<p>A similar link exists between the emergence of leaves and the insect herbivores that graze on them. The rapidity of climate change and slight differences in how the two groups respond risk breaking this synchrony with serious consequences for both sides.</p>
<p><a href="https://royalsocietypublishing.org/doi/10.1098/rspb.2021.2142">A large study</a> by German scientists looking at when flowers and their pollinators emerged between 1980 and 2020 found a complex picture. Both responded to climate change with earlier flowering and appearances, but the plants had made a greater shift. </p>
<p>There was variation between insect groups, bees and butterflies had shifted in synchrony with the plants, but this wasn’t observed in hoverflies. There was also variation between species of these insects.</p>
<figure class="align-center ">
<img alt="A white butterfly on a purple flower." src="https://images.theconversation.com/files/578642/original/file-20240228-30-erxph1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/578642/original/file-20240228-30-erxph1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=409&fit=crop&dpr=1 600w, https://images.theconversation.com/files/578642/original/file-20240228-30-erxph1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=409&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/578642/original/file-20240228-30-erxph1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=409&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/578642/original/file-20240228-30-erxph1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=513&fit=crop&dpr=1 754w, https://images.theconversation.com/files/578642/original/file-20240228-30-erxph1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=513&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/578642/original/file-20240228-30-erxph1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=513&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Plants and insects co-evolved to emerge at roughly the same time in Spring.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/blackveined-white-butterfly-aporia-crataegi-perfect-79443766">Marek Mierzejewski/Shutterstock</a></span>
</figcaption>
</figure>
<p>Even when plants and their dependent insects change timings in synchrony, the next stage of the food chain may not be so flexible. Oak leaves are fed upon by the oak moth caterpillar. This, in turn, is the primary food of the chicks of birds such as blue tits and pied flycatchers <a href="https://www.nature.com/articles/s41559-018-0543-1">link text</a>. Chicks have hatched at roughly the same time, while oak leaves and caterpillars have appeared earlier and so far remain in synchrony. But for how long?</p>
<p>Blackthorn blossoms remain a welcome relief from winter and a sign that spring is on its way. But they are also a sign of climate change: an unfolding experiment on the timing and synchrony of plants and animals – and the intricate food chains that they are part of.</p><img src="https://counter.theconversation.com/content/223930/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Paul Ashton does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Rising air temperatures mean shorter winters and earlier springs.Paul Ashton, Professor of Botany, Edge Hill UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2199502024-02-21T13:18:35Z2024-02-21T13:18:35ZPotato plant radiation sensors could one day monitor radiation in areas surrounding power plants<figure><img src="https://images.theconversation.com/files/575459/original/file-20240213-24-b1fnxo.jpg?ixlib=rb-1.1.0&rect=0%2C16%2C3642%2C2714&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Fields of genetically modified potato plants could detect radiation. </span> <span class="attribution"><a class="source" href="https://newsroom.ap.org/detail/f4df32b6c6354b5389fd59adaae707aa?ext=true">AP Photo/John Miller</a></span></figcaption></figure><p>While expanding nuclear energy production would provide carbon-free power and can help countries around the world meet their <a href="https://unfccc.int/process-and-meetings/the-paris-agreement">climate goals</a>, nuclear energy could also come with some inherent risk. Radioactive pollution damages the environment, and it’s nearly impossible to detect without specialized equipment. But what if plants growing in the facility’s surrounding area could detect radiation pollution?</p>
<p>The mechanical radiation detectors currently used, <a href="https://remm.hhs.gov/civilian.htm">called dosimeters</a>, aren’t completely reliable – during previous nuclear <a href="https://world-nuclear.org/information-library/safety-and-security/safety-of-plants/chernobyl-accident.aspx">accidents such as Chernobyl</a>, they’ve failed or been <a href="https://www.spokesmanbooks.com/acatalog/Zhores_Medvedev.html">buried under rubble</a>. </p>
<p><a href="https://utia.tennessee.edu/person/?id=11899">Our team</a> of <a href="https://plantsciences.tennessee.edu/racheff/">plant scientists</a> at the University of Tennessee wanted to figure out alternatives to these mechanical radiation sensors to help address their historic failures, so we decided to build a <a href="https://doi.org/10.1111/pbi.14072">plant-based sensor for gamma radiation</a>. The sensor, called a phytosensor, is a potato plant that glows fluorescent green when exposed to radiation.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/MaaZjoHDvMo?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Dosimeters sense how large a dose of radiation something in an area exposed to radiation would absorb.</span></figcaption>
</figure>
<h2>Historic sensor problems</h2>
<p>Current nuclear energy production is <a href="https://world-nuclear.org/information-library/safety-and-security/safety-of-plants/safety-of-nuclear-power-reactors.aspx">considered safe by the World Nuclear Association</a>. But safety failures still happen, whether <a href="https://www.spokesmanbooks.com/acatalog/Zhores_Medvedev.html">from human error</a> or <a href="https://shop.elsevier.com/books/fukushima-accident/povinec/978-0-12-408132-1">natural disasters</a> such as earthquakes bringing the mechanical sensors offline – and that’s where our plant sensors could come in.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/571529/original/file-20240125-19-dnnjtj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A black and white photo showing a large explosion hole in a building, from an overhead view." src="https://images.theconversation.com/files/571529/original/file-20240125-19-dnnjtj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/571529/original/file-20240125-19-dnnjtj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/571529/original/file-20240125-19-dnnjtj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/571529/original/file-20240125-19-dnnjtj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/571529/original/file-20240125-19-dnnjtj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=504&fit=crop&dpr=1 754w, https://images.theconversation.com/files/571529/original/file-20240125-19-dnnjtj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=504&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/571529/original/file-20240125-19-dnnjtj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=504&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Radiation sensors can help inform responses to nuclear accidents. Pictured is damage from the 1986 Chernobyl accident.</span>
<span class="attribution"><span class="source">AP Photo/Volodymyr Repik</span></span>
</figcaption>
</figure>
<p>Mechanical radiation detection equipment needs electrical power and regular maintenance, both of which make them less reliable during emergencies. A plant-based sensor wouldn’t require either of these.</p>
<p>The kinds of disasters that take mechanical sensors offline might damage the potato sensors but most likely wouldn’t kill an entire planted field of potatoes. As long as some plant cells are still alive, the plant could function as a radiation sensor. </p>
<p>Though potato plants are tough, some disasters, like a wildfire, would damage plant sensors more than mechanical sensors. While our sensors could supplement mechanical sensors, they wouldn’t completely replace their use. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/568097/original/file-20240106-22-l84j8b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Two small potato plants in green and two in gray, shown from overhead, in a square pot filled with soil" src="https://images.theconversation.com/files/568097/original/file-20240106-22-l84j8b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/568097/original/file-20240106-22-l84j8b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/568097/original/file-20240106-22-l84j8b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/568097/original/file-20240106-22-l84j8b.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/568097/original/file-20240106-22-l84j8b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/568097/original/file-20240106-22-l84j8b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/568097/original/file-20240106-22-l84j8b.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Genetically modified potato plants acting as radiation sensors.</span>
<span class="attribution"><span class="source">Stewart lab</span></span>
</figcaption>
</figure>
<h2>Plants as sensors</h2>
<p>Unlike mammals, plants can tolerate a lot of radiation before they die.
Potato plants, for example, can survive <a href="https://doi.org/10.1111/pbi.14072">10 times the amount of radiation</a> that would kill a human. </p>
<p>We chose potato as our sensor organism because potato plants can tolerate high levels of radiation, they’re easy to grow using tubers and they can survive in a <a href="https://www.fao.org/faostat/en/#data/QCL/visualize">variety of environments across the globe</a>. </p>
<p>Radiation exposure <a href="https://pubs.acs.org/doi/10.1021/tx000020e">damages DNA inside an organism’s cells</a>. When this happens in plants, they enter a “red alert” scenario and activate many DNA repair genes to fix the problem. </p>
<p>My colleagues and I co-opted the <a href="https://doi.org/10.3389/fpls.2015.00885">DNA damage response pathway</a> in potato plants so that when exposed to radiation, the potato leaves made a green fluorescent protein. This fluorescent protein causes the sensor plants to emit a unique green fluorescent glow when exposed to gamma radiation. </p>
<p>While the human eye can’t see the green signature, drones used for <a href="https://doi.org/10.1016/j.compag.2023.107737">agricultural and environmental monitoring</a> can. The more green fluorescence produced by the plant, the higher the radiation intensity. So the sensors can tell you “yes, there’s radiation,” as well as roughly how much radiation there is. </p>
<p><a href="https://doi.org/10.1111/pbi.14072">In our tests</a>, the plants reported radiation eight hours after exposure, but that was also the earliest our team was able to check them.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/571530/original/file-20240125-17-ug1yul.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A small drone flying over a crop field, with a house in the background." src="https://images.theconversation.com/files/571530/original/file-20240125-17-ug1yul.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/571530/original/file-20240125-17-ug1yul.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/571530/original/file-20240125-17-ug1yul.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/571530/original/file-20240125-17-ug1yul.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/571530/original/file-20240125-17-ug1yul.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/571530/original/file-20240125-17-ug1yul.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/571530/original/file-20240125-17-ug1yul.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Drones, like the kinds used for agricultural monitoring, would be able to see whether the plants are lighting up, keeping humans out of the irradiated area.</span>
<span class="attribution"><a class="source" href="https://newsroom.ap.org/detail/DronesAgriculture/ab91c96f7c134734a9f0fc41c003e93b/photo?Query=agricultural%20drone&mediaType=photo&sortBy=&dateRange=Anytime&totalCount=130&digitizationType=Digitized&currentItemNo=17&vs=true&vs=true">AP Photo/Alex Brandon</a></span>
</figcaption>
</figure>
<p>Based on our testing, the current radiation phytosensor can report a minimum total dose of <a href="https://remm.hhs.gov/gray_definition.htm">10 gray of radiation</a> – a very lethal dose for a human. The sensors reported radiation eight hours after exposure to it, and they continued to do so for 10 or more days, depending on dose. </p>
<p>Mechanical sensors can detect far lower radiation levels in real time, rather than as a cumulative dose like the phytosensors detect. This makes mechanical sensors ideal for everyday monitoring of dangerous radiation within a power plant, while phytosensors are better suited to monitor the larger areas of land around a power plant.</p>
<p>The current sensor could monitor radiation levels for the general public in an emergency scenario where radioactive material could be anywhere within a large disaster area. Chernobyl contaminated an area <a href="https://www.iaea.org/newscenter/focus/chernobyl/faqs">about the size of Nebraska</a>, while Fukushima contaminated an <a href="https://www.mdpi.com/2227-9067/2/1/39">area about the size of New Jersey</a>. Most of this area had low-level contamination, with some hot spots.</p>
<p>Compared with mechanical sensors, phytosensors are slower and less sensitive, so they wouldn’t save anyone working inside the power plant, even if they were grown indoors. The current sensor could tell first responders where the hottest areas are during a large-scale disaster. After a disaster, it could inform regulators where it is safe for workers, and eventually the public, to return to. </p>
<p>We tested the sensor using an in-lab laser and camera, which are low-power and low-resolution devices. Actual drones with specialized detection systems would likely be able to detect lower radiation thresholds.</p>
<p>In addition to functioning similarly to mechanical radiation sensors, the potato-based radiation phytosensor is a living and growing organism that gets its energy from sunlight. This means that <a href="https://doi.org/10.1111/pbi.14072">the phytosensor is</a> self-repairing, self-propagating and self-powering, unlike mechanical sensors. Since potatoes grow from tubers, they don’t need to be replanted every year.</p>
<p>One obvious downside of the current sensor is that potato plants die in the winter, so during that season you’d lose the sensor. Our sensor gene potentially could be put into an evergreen species like a pine tree, but this sensor would need to be retested to understand its detection minimums and performance over time.</p>
<h2>Potential applications</h2>
<p>When used in combination with more sensitive mechanical sensors, the current radiation phytosensor could act as a fail-safe if a disaster <a href="https://world-nuclear.org/information-library/safety-and-security/safety-of-plants/fukushima-daiichi-accident.aspx">similar to Fukushima Daiichi</a> were to occur. </p>
<p>While there are many possibilities for incorporating phytosensors into our current monitoring systems, our team still has hurdles to cross before the plants can be deployed in the field. </p>
<p>First, nuclear regulators would have to determine whether this technology is safe and useful, given their expectations for radiation monitoring equipment. Then, the plant sensor would undergo rigorous evaluation by the USDA to determine whether the phytosensors would negatively affect ecosystems if released. </p>
<p>Overcoming these hurdles will require more research, which could take months given the growth time for plants. Despite the work ahead, radiation phytosensors could help protect people and the environment in the future as countries continue producing nuclear energy.</p><img src="https://counter.theconversation.com/content/219950/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Neal Stewart receives funding from federal organizations. This work was funded by the Defense Advanced Research Projects Agency. Neal Stewart is an inventor in plant biotechnology, though none of the technologies described in the Conversation article are patented. </span></em></p><p class="fine-print"><em><span>Robert Sears does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>What if plants in the area surrounding a nuclear reactor could act as radiation detectors, with the help of a drone?Robert Sears, Graduate Research Assistant in Plant Science, University of TennesseeNeal Stewart, Professor of Plant Sciences, University of TennesseeLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2225122024-02-20T23:26:55Z2024-02-20T23:26:55ZA botanical Pompeii: we found spectacular Australian plant fossils from 30 million years ago<figure><img src="https://images.theconversation.com/files/576662/original/file-20240220-28-l9zg5j.jpg?ixlib=rb-1.1.0&rect=39%2C65%2C8544%2C5709&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Details of a silicified fern fossil.</span> <span class="attribution"><span class="source">Geoff Thompson/Queensland Museum</span></span></figcaption></figure><p>The Australian continent is now geologically stable. But volcanic rocks, lava flows and a contemporary landscape dotted with extinct volcanoes show this wasn’t always the case.</p>
<p>Between 40 and 20 million years ago – during the <a href="https://www.britannica.com/science/Tertiary-Period">Eocene to Miocene epochs</a> – there was widespread volcano activity across eastern Australia. In places such as western Victoria and the Atherton Tablelands in Queensland, it was even more recent.</p>
<p>Erupting volcanoes can have devastating consequences for human settlements, as we know from Pompeii in Italy, which was buried by ash when Mount Vesuvius erupted in 79 CE. But ash falls and lava flows can also entomb entire forests, or at least many of the plants within them. </p>
<p>Our studies of these rare and unique plant time capsules are revealing exquisitely preserved fossil floras and new insights into Australia’s botanical history. This new work is published <a href="https://authors.elsevier.com/a/1idT5,UYEnjl1W">in the journal Gondwana Research</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/576661/original/file-20240220-16-fa264v.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A landscape with snow crested mountain in the background and ash layers covering plants next to a road" src="https://images.theconversation.com/files/576661/original/file-20240220-16-fa264v.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/576661/original/file-20240220-16-fa264v.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/576661/original/file-20240220-16-fa264v.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/576661/original/file-20240220-16-fa264v.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/576661/original/file-20240220-16-fa264v.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/576661/original/file-20240220-16-fa264v.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/576661/original/file-20240220-16-fa264v.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">This is what volcanoes can do to landscapes – super-heated gasses from the 2011–12 eruption of Puyehue-Cordon Caulle Volcano in Argentina killed the forest. After ten years, the forest has started to regrow.</span>
<span class="attribution"><span class="source">Andrew Rozefelds</span></span>
</figcaption>
</figure>
<h2>Remarkable preservation</h2>
<p>The most common volcanic rocks are basalts. The rich red soils derived from them are among the most fertile in Australia.</p>
<p>But the rocks in which fossils occur are buried under basalts or other volcanic rock, and are called silcretes – the name indicates their origins are from silica-rich groundwaters. Silica is the major constituent of sand, and familiar to most of us as quartz. </p>
<p>What makes the silcrete plant fossils so fascinating is the superfine preservation of plant material. This includes fine roots and root nodules, uncurling fern fronds and their underground stems, the soft outer bark of wood, feeding traces and <a href="https://www.amentsoc.org/insects/glossary/terms/frass/">frass</a> (powdery droppings) of insects, and even the delicate tissues and anatomy of fruits and seeds.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/576664/original/file-20240220-28-miohox.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Close-up of clearly visible fern leaves and fragments made up of amber coloured stone" src="https://images.theconversation.com/files/576664/original/file-20240220-28-miohox.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/576664/original/file-20240220-28-miohox.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/576664/original/file-20240220-28-miohox.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/576664/original/file-20240220-28-miohox.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/576664/original/file-20240220-28-miohox.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/576664/original/file-20240220-28-miohox.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/576664/original/file-20240220-28-miohox.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The foliage of a <em>Pteridium</em> fern, preserved in silcrete in exceptional detail.</span>
<span class="attribution"><span class="source">Geoff Thompson/Queensland Museum</span></span>
</figcaption>
</figure>
<p>For this fine preservation to occur, first there needs to be a rapid burial, like that from a volcanic eruption. Then, there has to be an abundant source of silica — a condition met when the volcanic rocks began to weather. </p>
<p>The process where silica infills and preserves plant structures is referred to as “<a href="https://en.wikipedia.org/wiki/Silicification">silicification</a>” or “permineralisation”. When plant material is buried, it provides acidic conditions that are ideal for this to happen. </p>
<p>And the process need not take millions of years. Overseas studies of plants <a href="https://doi.org/10.2110/palo.2012.p.12-064r">in hot springs</a> or undertaken <a href="https://doi.org/10.2110/palo.2012.p.12-064r">in the laboratory</a> have shown that some types of silica will quickly infiltrate wood and plant tissues.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/576663/original/file-20240220-24-49adlz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Close-up of a rocky amber and white material with bubble-like shapes within" src="https://images.theconversation.com/files/576663/original/file-20240220-24-49adlz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/576663/original/file-20240220-24-49adlz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/576663/original/file-20240220-24-49adlz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/576663/original/file-20240220-24-49adlz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/576663/original/file-20240220-24-49adlz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/576663/original/file-20240220-24-49adlz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/576663/original/file-20240220-24-49adlz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">This is a cross-section of the stem (rhizome) of a silicified fern, showing its characteristic anatomy.</span>
<span class="attribution"><span class="source">Geoff Thompson/Queensland Museum</span></span>
</figcaption>
</figure>
<h2>Why are these plant fossils significant?</h2>
<p>Because of their rapid entombment by the volcanoes, we can be sure the plants were in situ (that is, their original location) and were actively growing. This means we can gain detailed information about the make-up of these past plant communities.</p>
<p>In other areas where plant fossils might accumulate – such as river deltas – we can never be sure how far the bits of plants were carried, and whether they were from different types of vegetation.</p>
<p>Silicification not only preserves plants, but also leaf litter on the forest floor and even the underlying soil containing roots and root nodules. The fossil plants that are preserved at different sites varies, indicating the presence of distinct plant communities. </p>
<p>The abundance of seeds and fruits at one site near Capella, in central Queensland, even indicated to us that the local volcanic eruptions are likely to have occurred in summer or early autumn during the fruiting season.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/576665/original/file-20240220-26-49adlz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A detailed folded shape of a seed encased in orange-amber rock" src="https://images.theconversation.com/files/576665/original/file-20240220-26-49adlz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/576665/original/file-20240220-26-49adlz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/576665/original/file-20240220-26-49adlz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/576665/original/file-20240220-26-49adlz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/576665/original/file-20240220-26-49adlz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/576665/original/file-20240220-26-49adlz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/576665/original/file-20240220-26-49adlz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">This cross-section of a silicified native grape seed shows its complex internal structure which is typical of the seeds of this family.</span>
<span class="attribution"><span class="source">Geoff Thompson/Queensland Museum</span></span>
</figcaption>
</figure>
<p>The extraordinary preservation of these fossils allows us to compare them with modern plants. In turn, this means we can accurately identify them.</p>
<p>The ferns include fronds and underground stems (rhizomes) of the familiar bracken fern (<em>Pteridium</em>). We have also found the distinctive seeds and lianas of the grape family (Vitaceae), along with evidence of insect damage in the wood. Two sites also had evidence of palms.</p>
<p>While there have been few previous studies on silcrete plants, we have revealed new insights into the history of the modern Australian flora.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/576667/original/file-20240220-18-ycxe50.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Close-up of a bright green pointy leaved fern with sun shining from behind it" src="https://images.theconversation.com/files/576667/original/file-20240220-18-ycxe50.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/576667/original/file-20240220-18-ycxe50.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=398&fit=crop&dpr=1 600w, https://images.theconversation.com/files/576667/original/file-20240220-18-ycxe50.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=398&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/576667/original/file-20240220-18-ycxe50.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=398&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/576667/original/file-20240220-18-ycxe50.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/576667/original/file-20240220-18-ycxe50.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/576667/original/file-20240220-18-ycxe50.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A modern bracken fern found in Queensland – the clear successor of the ferns found in the silcrete rocks.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/fern-north-queensland-rainforest-australia-2400181713">AustralianCamera/Shutterstock</a></span>
</figcaption>
</figure>
<h2>Volcanoes shaped plant communities</h2>
<p>Volcanic activity both destroys and modifies existing plant communities. It also provides new substrates for plants to colonise.</p>
<p>Several sites contained ferns – this may be because they are among the first living plants to colonise new volcanic terrains via their tiny wind-borne spores. For instance, <a href="https://doi.org/10.2307/2937282">it has been documented</a> that bracken ferns were pioneer plants of the barren cone of the <a href="https://theconversation.com/krakatoa-is-still-active-and-we-are-not-ready-for-the-tsunamis-another-eruption-would-generate-147250">famous Krakatoa volcano</a> after its eruption in 1883.</p>
<p>But the diversity of seeds and fruits at another site suggests that an existing forest was buried by volcanic activity. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/576668/original/file-20240220-30-2d7f7g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A star shaped impression embedded in an orange-amber rock" src="https://images.theconversation.com/files/576668/original/file-20240220-30-2d7f7g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/576668/original/file-20240220-30-2d7f7g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/576668/original/file-20240220-30-2d7f7g.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/576668/original/file-20240220-30-2d7f7g.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/576668/original/file-20240220-30-2d7f7g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/576668/original/file-20240220-30-2d7f7g.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/576668/original/file-20240220-30-2d7f7g.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">This star-shaped fruit, seen in cross section here, is currently being studied and is likely to be a species new to science.</span>
<span class="attribution"><span class="source">Geoff Thompson/Queensland Museum</span></span>
</figcaption>
</figure>
<p>Researchers have suggested that the key factors responsible for the evolution of the Australian fauna and flora during the Cenozoic period (the last 66 million years) were predominantly climate and environmental change. It happened, in part, due to the movement of the Australian continental plate northwards.</p>
<p>But the broad-scale volcano activity that occurred in eastern Australia during the Cenozoic has rarely been invoked as a key driver of such changes. </p>
<p>So remarkably preserved, the silcrete plant fossils are now providing startling new insights into the history of some groups of Australian plants and the vegetation types in which they grew. </p>
<hr>
<p><em>The author would like to acknowledge co-author Raymond Carpenter from the University of Adelaide who contributed to this article.</em></p><img src="https://counter.theconversation.com/content/222512/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Andrew Rozefelds receives funding from the Herman Slade Foundation and Churchill Trust, Australia.</span></em></p>Millions of years ago, widespread volcano eruptions in eastern Australia buried entire forests. Today, these time capsules reveal stunningly fossilised plants.Andrew Rozefelds, Adjunct Assoc Professor Central Queensland University and Principal Curator Geosciences Queensland Museum, CQUniversity AustraliaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2151272024-02-13T13:20:14Z2024-02-13T13:20:14ZFlowers grown floating on polluted waterways can help clean up nutrient runoff and turn a profit<figure><img src="https://images.theconversation.com/files/573604/original/file-20240205-30-14awa7.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C6173%2C4087&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The cut flowers could pay for themselves and even turn a profit.</span> <span class="attribution"><span class="source">Margi Rentis</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>Flowers grown on inexpensive floating platforms can help clean polluted waterways, over 12 weeks extracting 52% more phosphorus and 36% more nitrogen than the natural nitrogen cycle removes from untreated water, according to our <a href="https://doi.org/10.1016/j.envadv.2023.100405">new research</a>. In addition to filtering water, the cut flowers can generate income via the <a href="https://www.ers.usda.gov/data-products/chart-gallery/gallery/chart-detail/?chartId=106472">multibillion-dollar floral market</a>. </p>
<p>In our trials of various flowers, giant marigolds stood out as the most successful, producing long, marketable stems and large blooms. Their yield matched typical <a href="https://www.lsuagcenter.com/articles/page1662131594449">flower farm production</a>.</p>
<h2>Why it matters</h2>
<p><a href="https://www.epa.gov/nps/basic-information-about-nonpoint-source-nps-pollution">Water pollution</a> is caused in large part by runoff from farms, urban lawns and even septic tanks. When it rains, excess phosphorus, nitrogen and other chemicals wash into lakes and rivers.</p>
<p>These nutrients feed algae, leading to widespread and harmful algae blooms, which can severely lower oxygen in water, creating “<a href="https://unstats.un.org/sdgs/report/2021/goal-14/">dead zones</a>” where aquatic life cannot survive. Nutrient runoff is a critical issue as urban areas expand, affecting the health of water ecosystems. </p>
<p>Water pollution is an escalating crisis in our area of Miami-Dade and Broward counties in Florida. The <a href="https://storymaps.arcgis.com/stories/b5d43852c8984a4c8db4d077ec04bd35">2020 Biscayne Bay fish kill</a>, the largest mass death of aquatic life on record for the region, serves as a stark reminder of this growing environmental issue.</p>
<h2>How we do our work</h2>
<p>We study <a href="https://case.fiu.edu/earth-environment/agroecology/">sustainable agriculture</a> and <a href="https://crestcache.fiu.edu/">water pollution</a> in South Florida.</p>
<p>Inspired by traditional floating farm practices, including the Aztecs’ <a href="https://www.bbc.com/travel/article/20221009-the-return-of-aztec-floating-farms">chinampas in Mexico</a> and the <a href="https://www.pbs.org/video/the-secret-islands-of-the-everglades-lncj6r/">Miccosukees’ tree island settlements in Florida</a>, we tested the idea of growing cut flowers on floating rafts as a way to remove excess nutrients from waterways. Our hope was not only that the flowers would pay for themselves, but that they could provide jobs here in Miami, the center of the U.S. cut-flower trade.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/573507/original/file-20240205-23-zkmaeu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="An outdoor tank contains a large floating perforated mat. Each hole contains a young plant." src="https://images.theconversation.com/files/573507/original/file-20240205-23-zkmaeu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/573507/original/file-20240205-23-zkmaeu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/573507/original/file-20240205-23-zkmaeu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/573507/original/file-20240205-23-zkmaeu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/573507/original/file-20240205-23-zkmaeu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/573507/original/file-20240205-23-zkmaeu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/573507/original/file-20240205-23-zkmaeu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Chemical conditions in the test tanks were the same as in nearby polluted waterways.</span>
<span class="attribution"><span class="source">Jazmin Locke-Rodriguez</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>We floated 4-by-6-foot (1.2-by-1.8-meter) mats of inexpensive polyethylene foam called <a href="http://www.beemats.com/">Beemats</a> in 620-gallon (2,300-liter) outdoor test tanks that mirrored water conditions of nearby polluted waterways. Into the mats we transplanted flower seedlings, including zinnias, sunflowers and giant marigolds. The polluted tank water was rich in nutrients, eliminating the need for any fertilizer. As the seedlings matured into plants over 12 weeks, we tracked the tanks’ improving water quality. </p>
<p>Encouraged by the success of the marigolds in our tanks, we moved our trials to the nearby canals of Coral Gables and Little River. We anchored the floating platforms with 50-pound (22.7-kilograms) weights and also tied them to shore for extra stability. No alterations to the landscape were needed, making the process simple and doable.</p>
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<a href="https://images.theconversation.com/files/573517/original/file-20240205-15-ot28qz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Closeup photo of base of a marigold plant showing a tangle of visible roots." src="https://images.theconversation.com/files/573517/original/file-20240205-15-ot28qz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/573517/original/file-20240205-15-ot28qz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/573517/original/file-20240205-15-ot28qz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/573517/original/file-20240205-15-ot28qz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/573517/original/file-20240205-15-ot28qz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/573517/original/file-20240205-15-ot28qz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/573517/original/file-20240205-15-ot28qz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Some plants grow roots in places – such as the stem – other than where their original roots began.</span>
<span class="attribution"><span class="source">Jazmin Locke-Rodriguez</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>What still isn’t known</h2>
<p>The success of the giant marigolds might be linked to the extra roots that grow from their stems known as <a href="https://propg.ifas.ufl.edu/05-cuttings/01-terminology/01-cuttingterms-adventitiousroot.html">adventitious roots</a>. These roots likely help keep the plants stable on the floating platforms. Identifying additional plants with roots like these could help broaden plant choices. </p>
<p>Future raft designs may also need modifications to ensure better stability and growth for other cut-flower and crop species. </p>
<h2>What’s next</h2>
<p>Our promising findings show floating cut-flower farms could be a sustainable option for mitigating water pollution. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/Nim52wi_4z4?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">How floating cut-flower farms can clean polluted waterways.</span></figcaption>
</figure>
<p>One of us (Locke-Rodriguez) is expanding this research and working to scale up floating farms in South Florida as a demonstration of what could take place in the many locations facing similar issues worldwide.</p>
<p><em>The <a href="https://theconversation.com/us/topics/research-brief-83231">Research Brief</a> is a short take on interesting academic work.</em></p><img src="https://counter.theconversation.com/content/215127/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jazmin Locke received funding from the USDA-NIFA-NNF and NSF-CREST as a PhD student to help fund this dissertation research at Florida International University.</span></em></p><p class="fine-print"><em><span><a href="mailto:jayachan@fiu.edu">jayachan@fiu.edu</a> receives funding from USDA-NIFA. </span></em></p>Phosphorus and nitrogen contribute to water pollution and cause harmful algal blooms. New research shows how mats of floating flower beds can take advantage of these nutrients while cleaning the water.Jazmin Locke-Rodriguez, Post Doctoral Associate in the Institute of Environment, Florida International UniversityKrishnaswamy Jayachandran, Professor of Agroecology, Florida International UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2225622024-02-07T12:03:07Z2024-02-07T12:03:07ZUK peatlands are being destroyed to grow mushrooms, lettuce and houseplants – here’s how to stop it<figure><img src="https://images.theconversation.com/files/573477/original/file-20240205-17-9w5rwe.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Peat is a natural carbon sink but is often found in house plants and other retail products, particularly within the food and farming industry. </span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/woman-transplanting-houseplant-into-new-pot-2321168311">New Africa/Shutterstock</a></span></figcaption></figure><p>During the long, solitary days of lockdown, I found solace in raising houseplants. Suddenly stuck at home, I had more time to perfect the watering routine of a fussy Swiss cheese plant, and lovingly train our devil’s ivy to delicately frame the bookcases. </p>
<p>But I started noticing that these plants, sourced online, often arrived in the post with a passport. Most had travelled from all over Europe, with one common tagline: contains peat.</p>
<p>As a peatland scientist, these labels instantly filled me with horror. <a href="https://www.wildlifetrusts.org/ban-sale-peat">Hidden Peat</a>, a new campaign launched by The Wildlife Trusts, is now highlighting the presence of peat in all sorts of consumer products, including house plants. </p>
<p>Peatlands, such as bogs and fens, store more carbon than all of the <a href="https://www.iucn.org/resources/issues-brief/peatlands-and-climate-change">world’s forests combined</a>. They trap this carbon in the ground for centuries, preventing it from being released into the atmosphere as greenhouse gases that would further warm the climate. </p>
<p>Peatlands have <a href="https://www.ons.gov.uk/economy/environmentalaccounts/bulletins/uknaturalcapitalforpeatlands/naturalcapitalaccounts">multiple environmental benefits</a>. They are havens for wildlife, providing habitat for wetland birds, insects and reptiles. They supply more than 70% of our drinking water and help protect our homes from flooding. </p>
<p>So why on earth is peat being ripped from these vital ecosystems and stuffed inside plant pots?</p>
<h2>From sink to source</h2>
<p>Despite their importance, peatlands have been systematically drained, farmed, dug up and sold over the last century. In the UK, only <a href="https://assets.publishing.service.gov.uk/media/649d6fe1bb13dc0012b2e349/lowland-agricultural-peat-task-force-chairs-report.pdf">1% of lowland peat</a> remains in its natural state. </p>
<p>Instead of acting as a carbon sink, it has become one of the <a href="https://oro.open.ac.uk/50635/">largest sources</a> of greenhouse gas emissions in the UK’s land use sector. When waterlogged peat soils are drained, microbes decompose the plant material within it and that results in the <a href="https://www.ceh.ac.uk/sites/default/files/Peatland%20factsheet.pdf">release of greenhouse gases</a> such as methane into the air. </p>
<p>Most of the peat excavated, bagged up and sold in the UK is used as a growing medium for plants. Gardeners have become increasingly aware of this problem. Peat-free alternatives have been gaining popularity and major retailers have been phasing out peat-based bagged compost in recent years. </p>
<p>Indeed, the UK government announced they would ban sales of all peat-based compost <a href="https://www.gov.uk/government/news/sale-of-horticultural-peat-to-be-banned-in-move-to-protect-englands-precious-peatlands">by 2024</a>. But this legislation has not yet been written and it seems unlikely it will be enacted before the end of the current parliament. </p>
<p>Even if brought in to law, this ban would only stop the sales of peat-based bagged compost of the type you might pick up in the garden centre. Legislation for commercial growers is not expected until 2030 at the earliest. So the continued decimation of the UK’s peatlands could remain hidden in supply chains long after we stop spreading peat on our gardens. </p>
<h2>Hide and seek peat</h2>
<p>For consumers, it’s almost impossible to <a href="https://www.wildlifetrusts.org/news/devastating-using-peat-uk-horticulture#:%7E:text=In%202020%20alone%2C%20nearly%20900%2C000%20cubic%20metres%20of%20peat%20were%20extracted%20from%20UK%20soils%2C%20with%20a%20further%201.4%20million%20cubic%20metres%20of%20peat%20imported%20from%20Ireland%20and%20the%20rest%20of%20Europe">identify products</a> that contain peat or use peat in their production. All large-scale commercial mushroom farming involves peat and it is used for growing most leafy salads. It gives that characteristic peaty aroma to whisky, and, as I found out, is a popular growing medium for potted plants. </p>
<p>But you’d struggle to find a peat-free lettuce in the supermarket. The Hidden Peat campaign asks consumers to call for clear labelling that would enable shoppers to more easily identify peat-containing products. Shoppers are also encouraged to demand transparency from retailers on their commitment to removing peat from their supply chains. </p>
<p>You can ask your local supermarket about how they plan to phase out peat from their produce. Some supermarkets are actively investing in new technologies for <a href="https://www.newscientist.com/article/2326773-uk-mushroom-growing-uses-100000-m%25c2%25b3-of-peat-a-year-can-we-do-better/">peat-free mushroom farming</a>. </p>
<p>Make informed purchases by checking the labels on garden centre potted plants or source plants from peat-free nurseries. The Royal Horticultural Society lists more than 70 UK nurseries dedicated to <a href="https://www.rhs.org.uk/advice/peat/peat-free-nurseries">peat-free growing</a>. </p>
<p>You can write to your MP to support a ban on peat extraction and, crucially, the sale of peat and peat-containing products in the UK. That ensures that peat wouldn’t just get imported from other European countries. </p>
<h2>Pilots and progress</h2>
<p>The UK government recently announced <a href="https://www.gov.uk/government/publications/lowland-agricultural-peat-water-for-peat-pilots/lowland-agricultural-peat-water-for-peat-pilots">£3.1m funding</a> for pilot projects to rewet and preserve lowland peat, with peat restoration seen as a cornerstone of net zero ambitions. This campaign calls for further acceleration of peatland restoration across the UK. </p>
<p>As a research of the science behind <a href="https://www.linkedin.com/pulse/fin-ring-hrubesh-peatland-restoration">peatland restoration</a>, I see firsthand the enormous effort involved in this: the installation of dams to block old agricultural drainage ditches, the delicate management of water levels and painstaking monitoring of the peat wetness.</p>
<p>I spend a lot of time taking samples, monitoring the progress, feeding results back to the land managers. Like many other conservationists, I work hard to find ways to preserve these critical habitats. </p>
<p>But sometimes, there may be a digger in the adjacent field doing more damage in a day than we could undo in a lifetime. That’s the reality, and the insanity, of the UK’s current peatland policies. </p>
<p>We heavily invest in restoring peatlands, yet fail to ban its extraction – the one action that would have the most dramatic impact. By demanding that peat is not only eradicated from garden compost, but weeded out of our supply chains, we can keep peat in the ground, not in pots.</p>
<hr>
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<img alt="Imagine weekly climate newsletter" src="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<p><strong><em>Don’t have time to read about climate change as much as you’d like?</em></strong>
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<p class="fine-print"><em><span>Casey Bryce works with the Somerset Wildlife Trust to monitor peat restoration, funded by the University of Bristol department for alumni relations. </span></em></p>Hidden Peat, a new campaign from The Wildlife Trusts, encourages people to look out for peat-free alternatives and support their wider use.Casey Bryce, Senior Lecturer, School of Earth Sciences, University of BristolLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2225682024-02-05T13:29:42Z2024-02-05T13:29:42ZAmid growing legalization, cannabis in culture and politics is the focus of this anthropology course<figure><img src="https://images.theconversation.com/files/572920/original/file-20240201-19-efs8pb.jpg?ixlib=rb-1.1.0&rect=0%2C25%2C3456%2C2214&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Laws that govern cannabis use are changing across the nation.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/marijuana-legalization-high-quality-stock-photo-royalty-free-image/1143280562?phrase=cannabis">Darren415 via Getty Images</a></span></figcaption></figure><figure class="align-right ">
<img alt="Text saying: Uncommon Courses, from The Conversation" src="https://images.theconversation.com/files/499014/original/file-20221205-17-kcwec8.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/499014/original/file-20221205-17-kcwec8.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=375&fit=crop&dpr=1 600w, https://images.theconversation.com/files/499014/original/file-20221205-17-kcwec8.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=375&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/499014/original/file-20221205-17-kcwec8.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=375&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/499014/original/file-20221205-17-kcwec8.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=471&fit=crop&dpr=1 754w, https://images.theconversation.com/files/499014/original/file-20221205-17-kcwec8.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=471&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/499014/original/file-20221205-17-kcwec8.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=471&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<p><em><a href="https://theconversation.com/topics/uncommon-courses-130908">Uncommon Courses</a> is an occasional series from The Conversation U.S. highlighting unconventional approaches to teaching.</em> </p>
<h2>Title of course:</h2>
<p>Anthropology of Cannabis</p>
<h2>What prompted the idea for the course?</h2>
<p>Whenever I taught my medical anthropology course, I noticed that students were most curious about the section of the course that deals with the uses of plants, fungi and other species for a range of medical purposes. Those purposes included healing, psychological well-being, ritual and spiritual awakening, to name a few.</p>
<p>Once Connecticut, the state where I work, legalized recreational cannabis, I decided it was timely to take the plant section from the original course and expand it to a 14-week course of its own. It was also an opportunity to introduce students to the discipline of anthropology through a topic I knew many of them found interesting. I decided to focus on cannabis instead of the entire panoply of plants and other species, since it was the one plant being legalized in the state at that time.</p>
<h2>What does the course explore?</h2>
<p>Throughout the course, we focus on the different cultural and political significance of cannabis in other geographical contexts. We look at the representation of <a href="https://www.northernstandard.com/a-brief-history-of-cannabis-in-art/">cannabis in art</a>, <a href="https://electricliterature.com/7-lesser-known-stoner-novels-with-suggested-weed-pairings/">literature and pop culture</a>, as well as what the <a href="https://www.nccih.nih.gov/health/cannabis-marijuana-and-cannabinoids-what-you-need-to-know#:%7E:text=The%20cannabis%20plant%20contains%20about,on%20a%20person's%20mental%20state">science of cannabis</a> tells us about its <a href="https://doi.org/10.31887/DCNS.2020.22.3/mcrocq">impact on health and well-being</a>.</p>
<p>We also look at the way stigma and racism impact cannabis users and producers in the United States and elsewhere.</p>
<p>We end the course with students writing letters to themselves in which they imagine how the legal and social landscape for cannabis will be in five years, in the U.S. as well as globally. I plan to send them these letters in 2028.</p>
<h2>Why is this course relevant now?</h2>
<p>While cannabis has long been a part of human existence, the legal and political landscape of cannabis production is rapidly changing. Even if they are not cannabis consumers, students will at least become more aware about the role that cannabis plays in today’s society.</p>
<p>Students may want to know how they can participate in the business side of cannabis. Or they may be interested in doing research on the uses and abuses of the plant.</p>
<p>The course also offers students a way to think about the stigma and discrimination faced by cannabis users and how different cultural systems define and treat behaviors that are deemed deviant. </p>
<h2>What’s a critical lesson from the course?</h2>
<p>My main objective is to have students develop an informed understanding of cannabis as a plant and as a cultural fact. I want them to approach the study of cannabis with an open mind and to walk away with a greater understanding of how harmful stigma can be to individuals in any society. I would hope everyone leaves informed and less inclined to stereotype others. </p>
<h2>What materials does the course feature?</h2>
<p>We read passages from <a href="https://facultyprofile.fairfield.edu/?uname=dcrawford">anthropologist David Crawford</a>’s “<a href="https://rowman.com/ISBN/9781498598187/Dealing-with-Privilege-Cannabis-Cocaine-and-the-Economic-Foundations-of-Suburban-Drug-Culture">Dealing with Privilege: Cannabis, Cocaine, and the Economic Foundations of Surburban Drug Culture</a>,” which challenges the stereotypes that many white people and politicians hold about drug dealing and also explores how drugs became raced and classed entities.</p>
<p>We also read “<a href="https://doi.org/10.1089/can.2022.0251">Understanding and Rebalancing: A Rapid Scoping Review of Cannabis Research Among Indigenous People</a>,” which gives students an opportunity to learn more about Indigenous peoples and cultures alongside learning more about the cannabis plant itself.</p>
<p>And we watch “<a href="https://www.imdb.com/title/tt0028346/">Reefer Madness</a>,” a 1936 film meant to be a cautionary tale about the presumed dangers of marijuana use.</p>
<h2>What will the course prepare students to do?</h2>
<p>Students leave the class better informed about cannabis as a plant and with a better appreciation for the complexity of “drugs” in society. I believe the class also helps students to become more informed citizens, since the laws that govern the use and research on cannabis and other related plants are as much a <a href="https://doi.org/10.1177/0091450919827605">political issue as they are social</a>.</p><img src="https://counter.theconversation.com/content/222568/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Hillary Jeanne Haldane does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Students are invited to imagine how the social, political and legal landscape for cannabis will look in the future.Hillary Jeanne Haldane, Professor of Anthropology, Quinnipiac UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2046732024-01-29T13:35:17Z2024-01-29T13:35:17ZThat sharp, green smell of freshly cut grass? It’s a plant’s cry for help – and it may work as a less toxic pesticide for farmers<figure><img src="https://images.theconversation.com/files/570226/original/file-20240118-15-wd2xly.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C4928%2C3260&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Green leaf volatiles are a plant's rapid response to threats.</span> <span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Green_leaf_vein.jpg">Star61/Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>Have you ever wondered about that sharp, green note that hits your nose when you mow the lawn or cut flower stems? Those are <a href="https://doi.org/10.1093/pcp/pcac117">green leaf volatiles, or GLVs</a>: easily evaporated oils that plants use to communicate with other plants and defend themselves against herbivores or pathogens like bacteria or fungi.</p>
<p>Almost every green plant can quickly <a href="https://doi.org/10.1093/pcp/pcac117">synthesize and release GLVs</a> when attacked, both directly warding off attackers as well as indirectly attracting predators of herbivores like insects and priming the plant’s other defense mechanisms. Researchers know that GLVs play an important role in protecting plants, but how they work remains unclear.</p>
<p>I am a <a href="https://sc.edu/study/colleges_schools/chemistry_and_biochemistry/our_people/students_researchers_emeritus/tan-arsuwongkul_sasimonthakan.php">biochemistry researcher</a>, and through a collaboration between the <a href="https://qianwanggroup.com/">Wang Lab</a> and <a href="http://research.cas.sc.edu/stratmann/">Stratmann Lab</a> of the University of South Carolina, my colleagues and I study how plant cells deploy green leaf volatiles. In our <a href="http://doi.org/10.1111/pce.14795">recently published research</a>, we identified the potential signaling pathways GLVs use to induce defense responses in tomato cells. Our ultimate goal is to figure out ways to use GLVs to control agricultural pests for cleaner farming.</p>
<h2>Defense systems in plants</h2>
<p>Plants employ many defense systems to protect themselves. The <a href="https://doi.org/10.3389/fpls.2019.00646">first line of defense</a> involves detecting microbial invaders and the presence of damage using <a href="https://doi.org/10.1146/annurev-phyto-082718-100146">damage-associated molecular patterns, or DAMPs</a>, which are molecules released by damaged or dying cells.</p>
<p>When a cell identifies a DAMP, it triggers an immune response and promotes repair mechanisms. It also leads to <a href="https://doi.org/10.3389/fpls.2021.795353">changes in calcium ion concentration</a>, further activating immune-related genes and proteins. DAMPs also <a href="https://doi.org/10.1111/jipb.13215">turn on proteins</a> common in many stress-signaling pathways that activate other defense responses.</p>
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<figcaption><span class="caption">Plants have several means of defense.</span></figcaption>
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<p>Many studies have shown that the <a href="https://doi.org/10.3389/fpls.2014.00578">effects of</a> <a href="https://doi.org/10.1111/nph.12977">GLVs are</a> <a href="https://doi.org/10.3389/fpls.2020.583275">similar to</a> <a href="https://doi.org/10.1584/jpestics.d18-020">DAMPs</a>. Therefore, my team and I wanted to prove whether GLVs may also act as DAMPs.</p>
<p>To do this, we studied which proteins are turned on or off in tomato cells. Chemically changing the structure of a protein through a process called <a href="https://doi.org/10.1038/ncb0502-e127">phosphorylation</a> turns it on or off. Protein phosphorylation plays a central role in regulating a great number of cellular processes and involves many signal transmission pathways. <a href="https://doi.org/10.1186%2Fgb-2005-6-9-230">Studying the phosphoproteome</a>, or all the proteins that are phosphorylated in one system, of tomato cells could help us compare the signaling pathways of GLVs and DAMPs.</p>
<p>We found that many of the proteins involved in green leaf volatile signaling pathways were involved in regulating stress. These included many components of DAMP signaling pathways, supporting our hypothesis that GLVs function like DAMPs in activating defense responses.</p>
<h2>Using GLVs in agriculture</h2>
<p>Agriculture often places significant pressure on natural resources and the environment. For example, the use of conventional pesticides can lead to <a href="https://theconversation.com/farmers-and-cropdusting-pilots-on-the-great-plains-worried-about-pesticide-risks-before-silent-spring-91976">environmental degradation and pest resistance</a>. </p>
<p><a href="https://doi.org/10.3389/fsufs.2021.619058">Biopesticides</a> are rising in popularity as a less toxic alternative. These are naturally occurring organisms or compounds that suppress the growth and spread of pests. For example, <a href="https://doi.org/10.1016/j.jafr.2021.100127">volatile organic compounds</a> from plants are a type of biopesticide that have been proven to allow for reduced use of synthetic insecticides to manage pests in stored food grains.</p>
<p>Therefore, GLVs may also be effective biopesticides in farming. One study has shown that GLVs can attract a plant pest, the <em>Apion miniatum</em> beetle, <a href="https://doi.org/10.3390/app13042253">to feed on</a> an invasive and difficult to control weed, <em>Rumex confertus</em>. In addition, field studies on wild tobacco plants found that releasing GLVs can attract enemies of herbivores. The presence of these herbivore competitors can not only control insect pests but also <a href="http://dx.doi.org/10.7554/elife.00007">increase the production of infested plants</a>.</p>
<p>With further research, we believe GLVs have the potential to naturally control pests and support sustainable agriculture.</p><img src="https://counter.theconversation.com/content/204673/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Sasimonthakan Tanarsuwongkul does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Green plants produce a specific gas when under attack to both directly ward off herbivores and pathogens and indirectly lure in herbivore predators.Sasimonthakan Tanarsuwongkul, Ph.D. Candidate in Biochemistry, University of South CarolinaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2216722024-01-24T17:39:06Z2024-01-24T17:39:06ZThe palm tree that lives beneath the rainforest floor<p>In the heart of western Borneo’s vibrant jungles, the edible fruits of the underground palm are well-known to the local people who snack on them. But this botanical marvel has remained unnoticed by the scientific community for so long because it flowers and bears fruit underground. </p>
<p>At first glance, <em>Pinanga subterranea</em>, a rare palm tree, it looks like a small plant or seedling. Compared to a typical palm tree, <em>Pinanga subterranea</em> looks more modest and dainty, making it well-suited for smaller spaces or dense forests. </p>
<p>Its bright red fruits stay almost completely hidden by the soil. So how does this underground superstar survive beneath the forest floor? </p>
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<img alt="" src="https://images.theconversation.com/files/513999/original/file-20230307-18-3frmra.gif?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/513999/original/file-20230307-18-3frmra.gif?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/513999/original/file-20230307-18-3frmra.gif?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/513999/original/file-20230307-18-3frmra.gif?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/513999/original/file-20230307-18-3frmra.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/513999/original/file-20230307-18-3frmra.gif?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/513999/original/file-20230307-18-3frmra.gif?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<p><em>Many people think of plants as nice-looking greens. Essential for clean air, yes, but simple organisms. A step change in research is shaking up the way scientists think about plants: they are far more complex and more like us than you might imagine. This blossoming field of science is too delightful to do it justice in one or two stories.</em> </p>
<p><em><a href="https://theconversation.com/topics/plant-curious-137238?utm_source=TCUK&utm_medium=linkback&utm_campaign=PlantCurious2023&utm_content=InArticleTop">This article is part of a series, Plant Curious</a>, exploring scientific studies that challenge the way you view plantlife.</em></p>
<hr>
<p>Plants grow by using their roots to absorb water and nutrients from the soil. They also need sunlight to make their own food through a process called photosynthesis. </p>
<p>Typically, the stems and leaves are above ground, reaching up towards the light. Palm trees usually develop their flowers and fruits above ground for pollination and seed dispersal.</p>
<p>However, <em>Pinanga subterranea</em> challenges this norm by flowering and fruiting underground, showcasing an extraordinary survival strategy that challenges what we already know about how plants usually make and distribute their seeds.</p>
<h2>Secrets of survival</h2>
<p>There are three possible reasons this palm grows flowers underground, as highlighted in 2023 by the research team <a href="https://nph.onlinelibrary.wiley.com/doi/full/10.1002/ppp3.10393">Royal Botanic Gardens, Kew,</a> with partners from Indonesia and Malaysia who outlined this discovery. First, its stem demonstrates saxophone growth, bending down and then back up. </p>
<p>Second, the leaves form a funnel, and when organic litter piles up, roots sneak in. They suggest that the litter collects faster than the stem grows, so it stays underground. </p>
<p>Third, its flower clusters are short and below the leaves, usually developing completely underground. </p>
<p>Little is known about how exactly pollination happens in this underground palm. Pollination by flying insects such as bees is difficult, yet this palm still has a fruit and seed set that’s close to the soil surface, suggesting efficient pollination. Insects, especially beetles that move deep down through the undergrowth, might carry pollen for <em>Pinanga subterranea</em>. </p>
<p>Another potential pathway is the process of self-pollination of a flower by pollen from the same flower. Alternatively, wild boars living in the Borneo forest have been seen to unearth the red berries so they might play a crucial role too.</p>
<h2>A master of mutation</h2>
<p>One thing is certain though. Plants adapt by making changes in their genes, through what’s known as epigenetics. These changes help plants survive stress and adapt. While some changes are temporary, others can last longer and affect how plants grow and develop. Some might even be passed on to future plant generations, helping them to <a href="https://www.frontiersin.org/articles/10.3389/fpls.2019.00246/full">adapt and evolve</a>.</p>
<p>Over time, climate change has seriously affected both the environment and the plants and crops we grow. Different environmental stresses caused by climate change, like extreme temperatures, drought and heavy rain, can make it harder for plants to grow well, affecting their quality. Pressures like these can lead to epigenetic changes.</p>
<p>For example, peanut flowers produce above-ground blossoms, but the <a href="https://www.nature.com/articles/s41598-020-69943-7">fruits mature underground</a>. This adaptation likely offers greater protection, as the underground environment provides a safer and more stable space for seed development, contributing to the plant’s overall survival and reproductive success. </p>
<p>A small Australian underground orchid has also adapted to develop both fruit and <a href="https://nph.onlinelibrary.wiley.com/doi/full/10.1002/ppp3.45">flowers underground</a>. With the help of fungi, this orchid survives and reproduces in a safer and more stable underground environment. </p>
<p>Through epigenetic adaptations, some plants, including <em>Pinanga subterranea</em>, can adjust to changes without altering the core instructions or DNA. It’s like a tree’s survival manual. </p>
<p>Epimutations are changes that happen more often than regular changes in instructions (genetic mutations). <em>Pinanga subterranea</em>‘s underground flowering showcases nature’s adaptability. </p>
<p>By using its epigenetic toolbox to master survival in a changing climate, this palm has evolved smart ways to adapt to tough conditions in Borneo’s tropical landscape. </p>
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<img alt="Imagine weekly climate newsletter" src="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<p><strong><em>Don’t have time to read about climate change as much as you’d like?</em></strong>
<br><em><a href="https://theconversation.com/uk/newsletters/imagine-57?utm_source=TCUK&utm_medium=linkback&utm_campaign=Imagine&utm_content=DontHaveTimeTop">Get a weekly roundup in your inbox instead.</a> Every Wednesday, The Conversation’s environment editor writes Imagine, a short email that goes a little deeper into just one climate issue. <a href="https://theconversation.com/uk/newsletters/imagine-57?utm_source=TCUK&utm_medium=linkback&utm_campaign=Imagine&utm_content=DontHaveTimeBottom">Join the 30,000+ readers who’ve subscribed so far.</a></em></p>
<hr><img src="https://counter.theconversation.com/content/221672/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Chungui Lu does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>A recently discovered palm tree has an unusual survival strategy - it flowers and fruits beneath the groundChungui Lu, Professor of Sustainable Agriculture, Nottingham Trent UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1962262024-01-03T13:19:09Z2024-01-03T13:19:09ZHow scientists are helping plants get the most out of photosynthesis<figure><img src="https://images.theconversation.com/files/563630/original/file-20231205-15-2tk9l4.jpg?ixlib=rb-1.1.0&rect=5%2C5%2C3860%2C2579&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/detail-leaf-backlit-showing-ribs-veins-96544981">italianestro/Shutterstock</a></span></figcaption></figure><p>Photosynthesis is the starting point for almost every food chain, sustaining most life on Earth. You would be forgiven, then, for thinking nature has perfected the art of turning sunlight into sugar. But that isn’t exactly true. If you struggle with life goals, it might reassure you to know even plants haven’t yet reached their full potential.</p>
<p>Every evolved trait is a trade-off between the benefit it provides and its <a href="https://www.journals.uchicago.edu/doi/full/10.1086/717897">cost in energy</a>. The plants we domesticated for food are only as good at converting sunlight to sugar as they had to be to survive and reproduce. From a given amount of sunshine, most plants convert less than 5% of that <a href="https://bigthink.com/the-future/artificial-photosynthesis-improve/">light</a> energy into biomass, and under some conditions, less than 1%. </p>
<p>We now have the knowledge and the tools to maximise photosynthesis in a range of food crops – but scientists aren’t just studying how we help plants become better at photosynthesis out of curiosity. Climate change-driven weather such as drought and flooding is destroying crops and <a href="https://www.nature.com/articles/s43017-023-00491-0">threatening crop yields</a> around the world. This research is about making sure we can grow enough food to feed ourselves.</p>
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<img alt="" src="https://images.theconversation.com/files/513999/original/file-20230307-18-3frmra.gif?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/513999/original/file-20230307-18-3frmra.gif?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/513999/original/file-20230307-18-3frmra.gif?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/513999/original/file-20230307-18-3frmra.gif?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/513999/original/file-20230307-18-3frmra.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/513999/original/file-20230307-18-3frmra.gif?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/513999/original/file-20230307-18-3frmra.gif?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<p><em>Many people think of plants as nice-looking greens. Essential for clean air, yes, but simple organisms. A step change in research is shaking up the way scientists think about plants: they are far more complex and more like us than you might imagine. This blossoming field of science is too delightful to do it justice in one or two stories.</em> </p>
<p><em><a href="https://theconversation.com/topics/plant-curious-137238?utm_source=TCUK&utm_medium=linkback&utm_campaign=PlantCurious2023&utm_content=InArticleTop">This article is part of a series, Plant Curious</a>, exploring scientific studies that challenge the way you view plantlife.</em></p>
<hr>
<p>Plants such as wheat sometimes mistakenly make a toxic substance called <a href="https://www.sciencedirect.com/topics/chemistry/2-phosphoglycolate">2-phosphoglycolate</a> which then has to be recycled inside the plant, costing it energy. Scientists call this <a href="https://www.sciencedirect.com/topics/medicine-and-dentistry/photorespiration">photorespiration</a>. It happens when an enzyme crucial to the photosynthesis process, <a href="https://www.sciencedirect.com/science/article/abs/pii/S0981942808000041">rubisco</a>, mistakenly latches on to an oxygen molecule instead of carbon dioxide.</p>
<p>Rubisco makes this mistake up to 40% of the time. It happens because there is now a lot more oxygen in the atmosphere than in the past, put there by the very first photosynthesisers, <a href="https://www.britannica.com/science/blue-green-algae">cyanobacteria</a> – microscopic organisms found in water. Rising temperatures cause more photorespiration too.</p>
<p>If we could prevent this mistake, it would leave plants more energy for photosynthesis. </p>
<h2>Capturing sunlight</h2>
<p>Our research project, <a href="http://www.photoboost.org/">PhotoBoost</a>, is looking at how to create a kind of internal bypass that reduces photorespiration in rice and potato plants, two of the world’s most important crops. </p>
<p>In the same way a coronary bypass diverts blood around narrow or clogged arteries in humans, the photorespiratory bypass gives plants the genetic tools they need to minimise rubisco’s mistake. Genes from cyanobacteria make this and other photosynthetic improvements possible because they host an array of enzymes for better sunlight management.</p>
<p>Other researchers are looking to plants such as maize, which have evolved their own means of dealing with photorespiration, as a source of inspiration – and genes – for <a href="https://www.ox.ac.uk/news/2017-10-19-breakthrough-efforts-supercharge-rice-and-reduce-world-hunger">rice</a>.</p>
<figure class="align-center ">
<img alt="Leafy green shoots growing out of well tilled soil, sun setting in the background" src="https://images.theconversation.com/files/563631/original/file-20231205-19-lrhpyi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/563631/original/file-20231205-19-lrhpyi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/563631/original/file-20231205-19-lrhpyi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/563631/original/file-20231205-19-lrhpyi.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/563631/original/file-20231205-19-lrhpyi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/563631/original/file-20231205-19-lrhpyi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/563631/original/file-20231205-19-lrhpyi.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">These plants may not be making the most of photosynthesis.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/sapling-mung-bean-agriculture-garden-light-1616176942">Lamyai/Shutterstock</a></span>
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<p>We’re also improving the speed at which plants respond to changes in light intensity, as this <a href="https://www.science.org/doi/10.1126/science.aai8878">affects photosynthesis</a> too. Plants shut off their photosynthetic machinery if they get too much sun (when light is more intense), after which they can be slow to restart photosynthesising when it gets cooler again – for example, when clouds roll over.</p>
<p>A research group in the US recently showed that speeding up this photoprotection process in soybean can lead to a <a href="https://www.science.org/doi/10.1126/science.adc9831">33% increase</a> in seed yield.</p>
<p>On PhotoBoost, we’re talking to researchers, agronomists and farmers all around the world to understand how to match the needs of society with this new frontier in plant science. According to Elizabete Carmo-Silva and Ana Moreira Lobo, colleagues at Lancaster University: “Climate change, declining yields and water stress constitute major challenges for food production this century.”</p>
<p>Their team investigates plant responses to light and temperature, paying particular attention to the rubisco enzyme. Higher yield is perhaps the most obvious gain from improving photosynthesis, but it will also help make plants more resilient to drought and heat stress.</p>
<h2>New tools</h2>
<p>A new tool in the crop breeder’s arsenal, <a href="https://pubmed.ncbi.nlm.nih.gov/24157548/">gene editing</a>, allows scientists to turn genes on and off, testing the effect they have on plant performance. Once we know their function, these genes can be suppressed, promoted or, as has been done in commercial crops <a href="https://www.fda.gov/food/agricultural-biotechnology/science-and-history-gmos-and-other-food-modification-processes#:%7E:text=1994%3A%20The%20first%20GMO%20produce,safe%20as%20traditionally%20bred%20tomatoes.">since the 1990s</a>, introduced through genetic modification.</p>
<p>At the Universidade Nova de Lisboa in Portugal, Nelson Saibo and Isabel Abreu told us the tools that plant breeders have are more “fine tuners” these days. Their team is using gene editing to improve photosynthesis in rice.</p>
<p>The potato farmers we recently spoke to in the east of England saw greater photosynthesis efficiency as a route to freeing up land for nature – for example, planting trees on ancient forest sites or restoring peatland in the Fens – as more efficient plants mean you need less of them to give the same crop yield. Their major concern was whether major UK retailers would be <a href="https://www.dailymail.co.uk/news/article-9276737/Co-op-British-supermarket-reject-GM-crops-animals-without-strict-assessments.html">willing to champion</a> genetically engineered crops.</p>
<p>As well as Photoboost, the European Union is funding other photosynthesis programmes through the <a href="http://gain4crops.eu/">Gain4crops</a> (sunflower) and <a href="https://www.capitalise.eu/crop-improvement/">Capitalise</a> (tomato, maize and barley) projects. Improving photosynthesis isn’t a silver bullet for many of the agricultural problems we face. But combining knowledge and new tools will help us get the most out of light.</p><img src="https://counter.theconversation.com/content/196226/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jonathan Menary receives funding from the European Union</span></em></p><p class="fine-print"><em><span>Sebastian Fuller receives funding from the European Commission and the UK National Institute for Health and Care Research </span></em></p><p class="fine-print"><em><span>Stefan Schillberg receives funding from the European Union</span></em></p>Plants aren’t always as good at photosynthesis as you might think. Our research project wants to help them.Jonathan Menary, Postdoctoral Researcher, Centre for Tropical Medicine and Global Health, University of OxfordSebastian Fuller, Researcher of Implementation Science, University of OxfordStefan Schillberg, Executive Director, Fraunhofer IMELicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2189752023-12-29T11:40:00Z2023-12-29T11:40:00ZThe secret world of puddles<figure><img src="https://images.theconversation.com/files/565473/original/file-20231213-16-omthqc.jpg?ixlib=rb-1.1.0&rect=0%2C209%2C4169%2C3093&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Puddles can be valuable wildlife havens.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/water-splash-shoes-mens-feet-hiking-1857225058">Maksim Safaniuk/Shutterstock</a></span></figcaption></figure><p>As the new year arrived in 2016, my home city of Newcastle upon Tyne was briefly the centre of <a href="https://www.theatlantic.com/entertainment/archive/2016/01/the-puddle/422955/">global attention</a> – for a puddle. The Drummond Puddle, as it was grandly known, was a watery hazard placed perfectly where converging footpaths funnelled a daily stream of victims to their doom. To the wonderment of the world, their fate was <a href="https://www.youtube.com/watch?v=uRXuE7PBdLI">livestreamed</a> over the internet to more than half a million viewers. </p>
<p>But puddles are not merely a source of delight for wicked-minded onlookers. We can all, surely, remember the joy of splashing in a puddle – a universal example of creative play and getting to know the environment.</p>
<p>And yet, the conservation value of these tiny sites is still largely unappreciated. For puddles can be valuable wildlife havens too.</p>
<p>One <a href="https://doi.org/10.1016/j.limno.2012.07.002">study</a> of the invertebrate inhabitants of puddles in the UK countryside found a majority of these sites had a high conservation value, primarily due to the rare, specialist animals they hosted. Puddles may be commonplace, but their wildlife need not be.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/uRXuE7PBdLI?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">This 2016 Periscope video shows people trying to avoid stepping in Newcastle’s Drummond Puddle.</span></figcaption>
</figure>
<h2>Your own private pool</h2>
<p>The tiny, fragmented, ephemeral world of puddles creates the ideal habitat for some species. The isolation and brief life of many of these mini-ponds keeps long-lived, larger predators and competitors at bay, opening up opportunities for more “live fast, die young” life. </p>
<p>In the UK, the most famous examples are the <a href="https://insidedio.blog.gov.uk/2018/10/22/an-exclusive-tour-around-the-plain/">fairy shrimps</a> of puddles on Salisbury Plain in Wiltshire. Large areas of Salisbury Plain are given over to military training, and the churning tracks of tanks create many temporary pools that house these muddy lodgers.</p>
<p>The eggs of the <a href="https://www.britannica.com/animal/fairy-shrimp">fairy shrimp</a> are resistant to drought. They remain dormant, but viable, for many years and are spread by the wind or, in the case of Salisbury Plain, are carried in the mud spattered on military vehicles. </p>
<p>When rain fills a track in the dried mud, fairy shrimp eggs hatch almost immediately. The shrimps grow quickly to lay a new generation of eggs before their puddle dries.</p>
<figure class="align-center ">
<img alt="Frozen puddles in tank tracks on Salisbury Plain." src="https://images.theconversation.com/files/565471/original/file-20231213-15-a9b1jz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/565471/original/file-20231213-15-a9b1jz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=355&fit=crop&dpr=1 600w, https://images.theconversation.com/files/565471/original/file-20231213-15-a9b1jz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=355&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/565471/original/file-20231213-15-a9b1jz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=355&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/565471/original/file-20231213-15-a9b1jz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=446&fit=crop&dpr=1 754w, https://images.theconversation.com/files/565471/original/file-20231213-15-a9b1jz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=446&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/565471/original/file-20231213-15-a9b1jz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=446&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Frozen puddles in tank tracks on Salisbury Plain, Wiltshire.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/snow-covered-frozen-iced-puddle-off-1914696466">Martin Hibberd/Shutterstock</a></span>
</figcaption>
</figure>
<p>Other landscapes also harbour important puddles that we have helped to create. The Lizard Peninsula in Cornwall supports a network of trackways that date back to pre-historic times. Temporary pools have developed within these trackways, supporting rare specialist plants like the <a href="https://www.conservationevidence.com/reference/pdf/4018">pygmy rush</a>. </p>
<p>In the US, over the past decade, the rare <a href="https://www.britannica.com/animal/clam-shrimp">clam shrimp</a> has <a href="https://urbanhabitats.org/v02n01/biodiversitypatterns_pdf.pdf">been found</a> in puddles on the dirt surface of a gas pipeline road in New Jersey. The clam shrimp had only previously been identified in a handful of sites in the north-eastern US.</p>
<h2>Puddle problems</h2>
<p>Human activity may also be creating puddles in urban landscapes. The rapid urbanisation of Beijing has been <a href="https://www.sciencedirect.com/science/article/pii/S1878029616302298">linked</a> with increasing the numbers of puddles in the Chinese capital, largely by accident as sites are demolished ready for new developments. As soon as the new build is started, however, these ponds are buried and lost.</p>
<p>The wildlife of urban puddles on roads and pavements has received much less attention compared with other urban habitats, such as flowerbeds or small ponds. But <a href="https://doi.org/10.12911/22998993/111463">research</a> in urban areas of south-east Poland shows that single-celled algae such as <a href="https://www.britannica.com/science/diatom">diatoms</a> and <a href="https://www.britannica.com/science/desmid">desmids</a> thrive in these puddle environments. </p>
<p><a href="https://www.sciencedirect.com/science/article/pii/S2530064420300225?via%3Dihub">Studies</a> in Brazil have also credited deforestation in the Xingu basin with driving “lentification” – creating water bodies that include puddles. Puddles in these more tropical regions of the world support the ominous presence of <a href="https://www.britannica.com/animal/mosquito-insect">mosquito larvae</a>. </p>
<p>The same safety from predators provided by puddles that benefits fairy and clam shrimps is also important to mosquitoes. In one <a href="https://www.researchgate.net/publication/335091956_Assessment_of_Physico-Chemical_and_Ecological_Variables_in_Selected_Natural_Breeding_Sites_of_Mosquitoes_in_Ibadan_Oyo_State_Nigeria">study</a> in Nigeria, <a href="https://www.britannica.com/animal/Anopheles"><em>Anopheles</em> mosquito</a> larvae were found in a higher proportion of road puddles than in other small water bodies.</p>
<p>Birds often look to exploit ponds and puddles, looking for drowned worms after prolonged rain. But worms are <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1744-7410.2007.00117.x">not that easy</a> to drown (although it varies by species). So maybe the sorry, soggy specimens stuck in puddles are just unlucky, slowed down as they flounder in the water, becoming very obvious to birds with an eye for an easy meal.</p>
<p>Puddles are, however, not a positive substitute for the problems caused by urbanisation and habitat loss. In Poland, birds using road puddles for a wash <a href="https://www.tandfonline.com/doi/full/10.1080/24750263.2022.2101699">risk</a> being killed by traffic. </p>
<h2>Planet puddle</h2>
<p>While we might be most familiar with the puddles of pavements and streets, there are natural puddle habitats too – and these are very widespread all over the planet. Puddles on ice sheets and glaciers called <a href="https://zslpublications.onlinelibrary.wiley.com/doi/abs/10.1111/jzo.12832">cryoconite holes</a> are home to a cosmopolitan fauna of <a href="https://www.britannica.com/animal/Devils-worm">nematode worms</a>, mites and the famously tough <a href="https://www.theguardian.com/science/2021/mar/20/tardigrades-natures-great-survivors">tardigrades</a>. </p>
<p>Puddles also occur in deserts, often as tiny rock pools. By arranging sticky traps around these rock pools, researchers in South Africa showed how wind dispersal <a href="https://link.springer.com/article/10.1007/s10750-009-9929-z">helps their inhabitants travel</a>. As the rock pools dried, the traps caught wind-borne eggs blowing in the dust, carrying a mix of <a href="https://www.britannica.com/animal/water-flea">waterfleas</a>, <a href="https://onlinelibrary.wiley.com/doi/10.1111/zsc.12505#:%7E:text=Laevicaudatan%20branchiopods%2C%20also%20called%20%E2%80%98smooth%20clam%20shrimps%E2%80%99%20or,90%25%20of%20which%20belong%20to%20the%20genus%20Lynceus.">pea shrimps</a> and <a href="https://www.britannica.com/animal/mite">mites</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/565472/original/file-20231213-25-qdygg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="An image of a tardigrade under a microscope." src="https://images.theconversation.com/files/565472/original/file-20231213-25-qdygg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/565472/original/file-20231213-25-qdygg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=341&fit=crop&dpr=1 600w, https://images.theconversation.com/files/565472/original/file-20231213-25-qdygg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=341&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/565472/original/file-20231213-25-qdygg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=341&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/565472/original/file-20231213-25-qdygg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=429&fit=crop&dpr=1 754w, https://images.theconversation.com/files/565472/original/file-20231213-25-qdygg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=429&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/565472/original/file-20231213-25-qdygg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=429&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Tardigrades are famed among biologists for their ability to survive conditions that would kill almost any other animal.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/tardigrade-water-bear-microscope-magnification-2111263538">Videologia/Shutterstock</a></span>
</figcaption>
</figure>
<p>Urban puddles might still be the toughest environment of all, compared with the puddles in these glacier and desert habitats. But in all cases, there is much more to puddles than meets the eye – not just tiny shrimps or marooned worms.</p>
<p>Some of the strange creatures they contain are much more conspicuous. Video coverage of the Drummond Pond in Newcastle in 2016 even captured some two-legged inhabitants that appeared to be large, mammalian and naked …</p>
<hr>
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<img alt="Imagine weekly climate newsletter" src="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
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<p class="fine-print"><em><span>Mike Jeffries does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Puddles are an often-ignored but crucial habitat for rare and unusual wildlife.Mike Jeffries, Associate Professor, Ecology, Northumbria University, NewcastleLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2170822023-12-07T19:19:04Z2023-12-07T19:19:04ZWe thought we’d find 200 species living in our house and yard. We were very wrong<figure><img src="https://images.theconversation.com/files/559530/original/file-20231115-19-q1g80l.jpeg?ixlib=rb-1.1.0&rect=0%2C42%2C4025%2C2685&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Dot-underwing moth (_Eudocima materna_) found in the researchers' yard.</span> <span class="attribution"><span class="source">Matthew Holden</span>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span></figcaption></figure><p>We are biodiversity researchers – an ecologist, a mathematician and a taxonomist – who were locked down together during the COVID pandemic. Being restricted to the house, it didn’t take long before we began to wonder how many species of plants and animals we were sharing the space with. So we set to work counting them all.</p>
<p>We guessed we would find around 200–300, and many of our colleagues guessed the same. </p>
<p>There was nothing extraordinary about our 400 square metre block of land in Annerley, a suburb of Brisbane in Queensland, Australia. Roughly half the block was occupied by a three-bedroom house.</p>
<p>What was extraordinary was the number of species we discovered there. As revealed in our just-published study, starting on the first day of lockdown and continuing over the course of a year, we catalogued <a href="https://doi.org/10.1002/ecy.4225">1,150 species</a> on our inner-city property.</p>
<h2>Familiar faces and rare recluses</h2>
<p>Many of the species were what any east coast suburban Australian would expect: ibises, brush turkeys, kookaburras, possums and flying foxes. But, surprisingly, others had rarely been recorded. </p>
<p>In fact, three of the 1,150 species had never been documented in Australia’s leading biodiversity database at that point. This included a rare mosquito, a sandfly and an <a href="https://en.wikipedia.org/wiki/Platydemus_manokwari">invasive flatworm</a> that can cause populations of native snails to decline. </p>
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<strong>
Read more:
<a href="https://theconversation.com/the-39-endangered-species-in-melbourne-sydney-adelaide-and-other-australian-cities-114741">The 39 endangered species in Melbourne, Sydney, Adelaide and other Australian cities</a>
</strong>
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<p>We found common foes, but also many friends. That rare mosquito was just one of 13 mosquito species we found. The cupboards accommodated pantry moths and grain weevils, but also spiders to prey on them (we recorded 56 species). </p>
<p>Our lack of assiduous garden-tending meant weeds were prolific; of the 103 plant species we documented on the property, 100 were non-native. </p>
<p>Apart from weeds, however, the vast majority of species were actually native. Our two massive lilly-pilly trees provided shade, shelter and food, magnets for numerous pollinators and other species. </p>
<h2>Bees and butterflies</h2>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/560107/original/file-20231117-27-3o9y36.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A photo of sleeping bees hanging on a plant stem." src="https://images.theconversation.com/files/560107/original/file-20231117-27-3o9y36.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/560107/original/file-20231117-27-3o9y36.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=889&fit=crop&dpr=1 600w, https://images.theconversation.com/files/560107/original/file-20231117-27-3o9y36.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=889&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/560107/original/file-20231117-27-3o9y36.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=889&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/560107/original/file-20231117-27-3o9y36.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1117&fit=crop&dpr=1 754w, https://images.theconversation.com/files/560107/original/file-20231117-27-3o9y36.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1117&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/560107/original/file-20231117-27-3o9y36.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1117&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Blue-banded bees sleep grasping plant stems with their mandibles.</span>
<span class="attribution"><span class="source">Andrew Rogers</span></span>
</figcaption>
</figure>
<p>The yard was filled with pollinators. For example, there were hoverflies which, at a quick glance, you’d think were wasps. We had ten species of those, a fraction of the more than 109 species of flies we found. </p>
<p>Native blue-banded bees and fluffy teddybear bees roosted in the hedges under our windows at night. They were just two of more than 70 bee and wasp species we observed. </p>
<p>We also counted a mindblowing 436 species of butterflies and moths. A few were as large as a human hand, but most were tiny and barely noticeable. Some were brightly coloured, while others – like the vampire moth <em>Calyptra minuticornis</em> – seemed boring until we began to study their behaviour. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1252048652337479681"}"></div></p>
<p>The moth <em>Scatochresis innumera</em> is another interesting one: as a caterpillar, it lives inside a single possum poop before emerging as an adult. </p>
<p>The caterpillars of <em>Parilyrgis concolor</em>, yet another moth, live in spiderwebs, surviving on the spider’s food waste, while the adults can be found hanging bat-like from the spiderwebs. It is not known how they avoid getting eaten by the spiders.</p>
<figure class="align-center ">
<img alt="A photo of a brown moth hanging from a spiderweb." src="https://images.theconversation.com/files/564100/original/file-20231207-27-e6h1m6.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/564100/original/file-20231207-27-e6h1m6.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=423&fit=crop&dpr=1 600w, https://images.theconversation.com/files/564100/original/file-20231207-27-e6h1m6.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=423&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/564100/original/file-20231207-27-e6h1m6.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=423&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/564100/original/file-20231207-27-e6h1m6.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=532&fit=crop&dpr=1 754w, https://images.theconversation.com/files/564100/original/file-20231207-27-e6h1m6.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=532&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/564100/original/file-20231207-27-e6h1m6.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=532&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The caterpillars of the moth Parilyrgis concolor live in spiderwebs, and adults often hang from webs like bats.</span>
<span class="attribution"><span class="source">Russell Yong</span></span>
</figcaption>
</figure>
<h2>Wasps and beetles</h2>
<p>We recorded ten species of lycaenid “blue” butterflies, many of which use ants to protect their caterpillars from predators, including certain wasp species which would lay eggs in them if they got a chance.</p>
<p>These wasps are called parasitoids – meaning their young develop in other organisms, eventually killing them. Some of these wasps even parasitise other parasitoid wasps. Our urban homes are clearly complex ecosystems.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/560183/original/file-20231117-19-6mz01y.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A photo of a small orange and black bug on a thin tree branch." src="https://images.theconversation.com/files/560183/original/file-20231117-19-6mz01y.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/560183/original/file-20231117-19-6mz01y.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=659&fit=crop&dpr=1 600w, https://images.theconversation.com/files/560183/original/file-20231117-19-6mz01y.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=659&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/560183/original/file-20231117-19-6mz01y.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=659&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/560183/original/file-20231117-19-6mz01y.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=828&fit=crop&dpr=1 754w, https://images.theconversation.com/files/560183/original/file-20231117-19-6mz01y.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=828&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/560183/original/file-20231117-19-6mz01y.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=828&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A tiny Braconid wasp that parasitises other insects.</span>
<span class="attribution"><span class="source">Matthew Holden</span></span>
</figcaption>
</figure>
<p>We were surprised to only find just under 100 beetle species (the fourth most common group of organisms in our study). Beetles are widely believed to be the most diverse order of insects on the planet. </p>
<p>Our finding may be a sign of declining beetle populations, which has been observed around the world. On the other hand, it may just have been a bad year for beetles in our neighbourhood.</p>
<h2>An urban environment teeming with life</h2>
<p>Overall, we found far more species than we expected, and we showed that even urban environments can be teeming with wildlife. </p>
<p>A big reason for that was surely the vegetation: the shrubs, trees and weeds in the yard. The monotony of perfectly tended lawn and heavily sprayed and manicured flowerbeds may be nice to look at and for the kids to play on but, as habitat for urban wildlife, it is lacking. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/heres-how-to-design-cities-where-people-and-nature-can-both-flourish-102849">Here's how to design cities where people and nature can both flourish</a>
</strong>
</em>
</p>
<hr>
<p>Our own laziness meant we did little work in the garden. However, by giving the mower and pesticides a break, and by sacrificing some lawn for native trees, shrubs and flowering weeds, we ended up with something much more valuable.</p>
<p>But no matter what you do to maintain your home, definitely check your porch or balcony light tonight, and keep your eye out for urban wildlife around your home. You too can experience some pretty amazing nature, no matter how urban the environment you live in.</p><img src="https://counter.theconversation.com/content/217082/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Matthew H. Holden receives funding from the Australian Research Council and the Department of Environment and Science, Queensland</span></em></p><p class="fine-print"><em><span>Andrew Rogers and Russell Q-Y Yong do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>An ecologist, a mathematician and a taxonomist were locked down together in a suburban house. So they counted all the species of plants and animals they could find.Matthew H. Holden, Lecturer, School of Mathematics and Physics, The University of QueenslandAndrew Rogers, PhD student, The University of QueenslandRussell Q-Y Yong, PhD candidate, Marine Parasitology, The University of QueenslandLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2152222023-11-21T13:27:15Z2023-11-21T13:27:15ZClimate change is already forcing lizards, insects and other species to evolve – and most can’t keep up<figure><img src="https://images.theconversation.com/files/558259/original/file-20231108-29-upppm0.jpg?ixlib=rb-1.1.0&rect=2%2C2%2C1615%2C1069&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Temperature sensitivity makes western fence lizards vulnerable to climate change.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/blmoregon/47961427128">Greg Shine/BLM</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>Climate change is threatening the survival of plants and animals around the globe as temperatures rise and habitats change.</p>
<p>Some species have been able to meet the challenge with rapid evolutionary adaptation and other changes in behavior or physiology. Dark-colored dragonflies are <a href="https://doi.org/10.1073/pnas.2101458118">getting paler</a> in order to reduce the amount of heat they absorb from the sun. Mustard plants are <a href="https://doi.org/10.1098/rspb.2012.1051">flowering earlier</a> to take advantage of earlier snowmelt. Lizards are <a href="https://doi.org/10.1098/rsbl.2020.0625">becoming more cold-tolerant</a> to handle the extreme variability of our new climate.</p>
<p>However, scientific studies show that climate change is occurring much faster than species are changing.</p>
<figure class="align-center ">
<img alt="A tiny, royal blue fish with gold stripes looks into the camera. The downward slant of its mouth and shadow at the top of its eye give it an annoyed look." src="https://images.theconversation.com/files/558243/original/file-20231108-23-xs3oy9.jpg?ixlib=rb-1.1.0&rect=8%2C8%2C5599%2C3724&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/558243/original/file-20231108-23-xs3oy9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/558243/original/file-20231108-23-xs3oy9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/558243/original/file-20231108-23-xs3oy9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/558243/original/file-20231108-23-xs3oy9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/558243/original/file-20231108-23-xs3oy9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/558243/original/file-20231108-23-xs3oy9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Zebrafish have evolved to thrive in water a degree or so warmer than normal, but they struggle to survive at higher temperatures.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/brachydanio-rerio-royalty-free-image/154930602?adppopup=true">isoft/E+ Getty Images</a></span>
</figcaption>
</figure>
<h2>What is evolutionary adaptation?</h2>
<p>The word “adaptation” is used in many ways by climate scientists, but it has a very specific meaning to biologists: It refers to genetic changes that are passed on from one generation to the next and improve a species’ ability to survive in its environment.</p>
<p>These genetic modifications make evolutionary adaptation different from “acclimation” or “acclimatization,” which involve advantages that are not passed on to offspring. For example, when people move to high-altitude cities, they <a href="http://dx.doi.org/10.1136/bjsports-2013-092840">start producing more red blood cells</a> as they acclimate to the low oxygen.</p>
<p>All over the world, plants and animals have adapted to many different warm and dry habitats, prompting scientists to <a href="https://doi.org/10.1098/rstb.2018.0176">question</a> <a href="https://doi.org/10.1038/s41586-019-1520-9">whether</a> <a href="https://doi.org/10.1111/gcb.14881">species</a> <a href="https://doi.org/10.1073/pnas.1406314111">might</a> <a href="https://doi.org/10.1111/evo.13862">also</a> <a href="https://doi.org/10.1126/science.1063656">adapt</a> <a href="https://doi.org/10.1073/pnas.0608379104">to</a> <a href="https://doi.org/10.1111/ele.14072">our</a> <a href="https://doi.org/10.1126/science.aba9287">rapidly</a> <a href="https://doi.org/10.1126/science.abj7484">changing</a> <a href="https://doi.org/10.1126/science.aaf3343">climate</a>, <a href="https://doi.org/10.1038/nclimate2628">too</a>.</p>
<p>Thus far, the answer <a href="https://doi.org/10.1002/wcc.852">seems to be no</a> for most species.</p>
<h2>Evolving, fast and slow</h2>
<p>A <a href="https://doi.org/10.1038/s41467-019-10924-4">recent study</a> of the populations of 19 bird and mammal species, including owls and deer, shows one potential barrier to adaptation. </p>
<p>In animals that take several years to reach breeding age, the climate has already shifted by the time their offspring are born. Genes that gave the parents an advantage – like hatching at exactly the right time or growing to the best size – are no longer as beneficial for the offspring.</p>
<p>Populations of these slow-maturing animals are adapting to climate change, but not enough during each generation to thrive in the changing conditions. In fact, the rate of evolution is so mismatched to the rate of global warming that the study’s authors estimate that nearly 70% of the local populations they studied are already vulnerable to climate-driven extinction over the coming decades.</p>
<figure class="align-center ">
<img alt="A dragonfly with dark bands on its wings." src="https://images.theconversation.com/files/558246/original/file-20231108-27-yipcvj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/558246/original/file-20231108-27-yipcvj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=408&fit=crop&dpr=1 600w, https://images.theconversation.com/files/558246/original/file-20231108-27-yipcvj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=408&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/558246/original/file-20231108-27-yipcvj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=408&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/558246/original/file-20231108-27-yipcvj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=512&fit=crop&dpr=1 754w, https://images.theconversation.com/files/558246/original/file-20231108-27-yipcvj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=512&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/558246/original/file-20231108-27-yipcvj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=512&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Black bands on dragonflies heat up their bodies. Research shows some dragonflies have evolved smaller black bands as the climate warms.</span>
<span class="attribution"><span class="source">Michael P. Moore</span></span>
</figcaption>
</figure>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/558248/original/file-20231108-27-nr1728.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A heat map clearly shows that the dark bands on the wings absorb more heat." src="https://images.theconversation.com/files/558248/original/file-20231108-27-nr1728.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/558248/original/file-20231108-27-nr1728.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/558248/original/file-20231108-27-nr1728.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/558248/original/file-20231108-27-nr1728.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/558248/original/file-20231108-27-nr1728.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/558248/original/file-20231108-27-nr1728.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/558248/original/file-20231108-27-nr1728.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">In this heat map of the same dragonfly, white areas are the warmest and purple areas are cooler. The dark bands on the wings stand out.</span>
<span class="attribution"><span class="source">Michael P. Moore</span></span>
</figcaption>
</figure>
<p>Small-bodied animals, such as many fish, insects and plankton, typically mature quickly. Yet, recent research on <a href="https://doi.org/10.1073/pnas.2011419117">small fish</a> and a type of <a href="https://doi.org/10.1098/rspb.2011.0542">fast-maturing plankton called a copepod</a> revealed another hurdle for rapid genetic adaptation to climate change.</p>
<p>Many species possess genes that permit them to live in environments that are 1 to 2 degrees Celsius (about 2 to 4 Fahrenheit) warmer than today, but new genetic mutations must arise to enable survival if climates reach 4 to 5 C (about 7 to 9 F) warmer, as is possible in some regions, particularly if greenhouse gas emissions continue at a high rate.</p>
<p>To test species’ resilience, scientists warmed populations of these fast-maturing species over many generations to observe their genetic changes. They found that both the copepods and the small fish were able to adapt to the first couple degrees of warming, but populations soon went extinct above that. This was because genetic mutations that increased their ability to live in hotter conditions occurred at a slower rate than the temperatures rose.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/558242/original/file-20231108-29-dkylc9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A tiny nearly translucent oval creature with a tail and egg sacks trailing behind it." src="https://images.theconversation.com/files/558242/original/file-20231108-29-dkylc9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/558242/original/file-20231108-29-dkylc9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=397&fit=crop&dpr=1 600w, https://images.theconversation.com/files/558242/original/file-20231108-29-dkylc9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=397&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/558242/original/file-20231108-29-dkylc9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=397&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/558242/original/file-20231108-29-dkylc9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=500&fit=crop&dpr=1 754w, https://images.theconversation.com/files/558242/original/file-20231108-29-dkylc9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=500&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/558242/original/file-20231108-29-dkylc9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=500&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A live copepod with egg sacs at 10 times magnification. These ocean creatures produce new generations quickly, allowing for speedier evolution.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/copepod-micrograph-royalty-free-image/170025374?adppopup=true">NNehring/E+ Getty Images</a></span>
</figcaption>
</figure>
<p>Cold-blooded species, such as lizards, frogs and fish, are especially vulnerable to climate change because they have a limited capacity to regulate their own body temperatures. Their ability to evolve in response to climate change is expected to be critical for their survival.</p>
<p>However, rapid adaptation to climate change often comes <a href="https://doi.org/10.1007/BF02984069">at a cost</a>: Populations get smaller due to the deaths of individuals that cannot tolerate new, hotter temperatures. Therefore, even if species do evolve to survive with climate change, their smaller populations may still go extinct due to problems such as inbreeding, harmful new mutations or plain old bad luck, such as a disease epidemic.</p>
<p><a href="https://doi.org/10.1126/science.1184695">In a now-classic study</a>, researchers studying lizards in Mexico discovered that the high death rates of just the heat-sensitive individuals – representing only a subset of the entire population – caused 12% of all lizard populations in Mexico to go extinct between 1975 and 2009. Even with some heat-tolerant adult lizards surviving in each population under the warmer conditions, the researchers estimated climate change would kill so many heat-sensitive adults within each population that 54% of all populations would go extinct by 2080.</p>
<h2>Evolutionary adaptation isn’t species’ only option</h2>
<p>Another way species adjust to rising temperatures is acclimation, sometimes called “phenotypic plasticity.” For example, <a href="https://doi.org/10.1126/science.1157174">great tits in the U.K.</a> – small birds that are common in yards and forests – lay their eggs earlier in warmer years so that their nestlings hatch right as the winter weather ends, no matter when that happens.</p>
<figure class="align-center ">
<img alt="A small bird with a yellow body and black head with white cheeks sits on a branch." src="https://images.theconversation.com/files/558258/original/file-20231108-21-3e6t6i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/558258/original/file-20231108-21-3e6t6i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=375&fit=crop&dpr=1 600w, https://images.theconversation.com/files/558258/original/file-20231108-21-3e6t6i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=375&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/558258/original/file-20231108-21-3e6t6i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=375&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/558258/original/file-20231108-21-3e6t6i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=471&fit=crop&dpr=1 754w, https://images.theconversation.com/files/558258/original/file-20231108-21-3e6t6i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=471&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/558258/original/file-20231108-21-3e6t6i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=471&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A great tit – <em>Parus major</em>. In the U.K., these common birds have been laying their eggs earlier in warm years.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/hedera_baltica/49433487712/in">Hedera.Baltica via Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>However, a <a href="https://www.nature.com/articles/s41467-022-32953-2">recent analysis</a> of more than 100 beetle, grasshopper and other insect species all over the world found that acclimation may not help those species enough. The study’s authors found that the species they reviewed gained an average of only 0.1 C (about 0.2 F) greater heat tolerance when acclimating to 1 C (about 2 F) warmer air temperatures during their development. Thus, the rate of global warming seems to be outstripping species’ abilities to acclimate, too.</p>
<p>Plants and animals could also escape the impacts of global warming by migrating to cooler habitats. A <a href="https://doi.org/10.1038/s41559-020-1198-2">global analysis</a> of more than 12,000 different plants and animal species recently showed that many species are migrating toward the poles fast enough to keep pace with rising temperatures, and many <a href="https://doi.org/10.1111/ele.13762">tropical species are moving upslope</a> to higher elevations as well.</p>
<p>Nonetheless, migration has its limits. Research shows that <a href="https://doi.org/10.1073/pnas.1804224115">tropical birds that already live high in the mountains could be doomed</a> because there is no room for them to migrate any farther upward. Tropical species, therefore, may be on what the authors call an “escalator to extinction.”</p>
<figure class="align-center ">
<img alt="A yellow-and-black moth sits on a yellow flower in an alpine field with snow-covered mountains in the background." src="https://images.theconversation.com/files/558253/original/file-20231108-21-ad3ofx.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/558253/original/file-20231108-21-ad3ofx.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=789&fit=crop&dpr=1 600w, https://images.theconversation.com/files/558253/original/file-20231108-21-ad3ofx.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=789&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/558253/original/file-20231108-21-ad3ofx.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=789&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/558253/original/file-20231108-21-ad3ofx.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=992&fit=crop&dpr=1 754w, https://images.theconversation.com/files/558253/original/file-20231108-21-ad3ofx.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=992&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/558253/original/file-20231108-21-ad3ofx.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=992&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Police car moths living at high elevations have little room to migrate to escape increasing heat.</span>
<span class="attribution"><span class="source">Michael P. Moore</span></span>
</figcaption>
</figure>
<p>High-latitude and high-elevation habitats also present numerous challenges for species to overcome besides temperature. Our own research across 800 species of insects all over the Earth shows that butterflies, bees and other flying insects are <a href="https://doi.org/10.1038/s41558-023-01794-2">especially hindered from migrating to higher elevations</a> because there is not enough oxygen for them to survive. </p>
<h2>Many species lack obvious climate strategies</h2>
<p>Overall, evolutionary adaptation appears to help lessen the impacts of global warming, but the evidence thus far shows that it is insufficient to overcome current rates of climate change. Acclimation and migration provide faster solutions, but research shows that those may not be enough, either.</p>
<p>Of course, not all evolution is driven by warming temperatures. Plant and animal species appear to be also gradually adapting to other kinds of environments, including <a href="https://doi.org/10.1111/evo.14191">human-created ones like cities</a>. But the fast pace of global warming makes it <a href="https://nca2023.globalchange.gov/chapter/8#fig-8-2">one of the major threats</a> that species must respond to immediately.</p>
<p>The <a href="https://nca2023.globalchange.gov/chapter/8#fig-8-2">evidence indicates</a> that humanity cannot simply assume that plants and animals will be able to save themselves from climate change. To protect these species, humans will have to stop the activities that are fueling climate change.</p><img src="https://counter.theconversation.com/content/215222/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>From dark dragonflies becoming paler to plants flowering earlier, some species are slowly evolving with the climate. Evolutionary biologists explain why few will evolve fast enough.Michael P. Moore, Assistant Professor of Biology, University of Colorado DenverJames T. Stroud, Assistant Professor of Ecology and Evolution, Georgia Institute of TechnologyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2177862023-11-17T20:56:02Z2023-11-17T20:56:02ZPlants are likely to absorb more CO₂ in a changing climate than we thought – here’s why<figure><img src="https://images.theconversation.com/files/560095/original/file-20231116-23-ylmksg.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C4493%2C2991&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/aerial-top-view-forest-tree-rainforest-2033096327">Olga Danylenko/Shutterstock</a></span></figcaption></figure><p>The world’s vegetation has a remarkable ability to absorb carbon dioxide (CO₂) from the air and store it as biomass. In doing so, plants slow down climate change since the CO₂ they take up does not contribute to global warming. </p>
<p>But what will happen under more advanced climate change? How will vegetation respond to projected changes in atmospheric CO₂, temperatures and rainfall? Our <a href="http://www.science.org/doi/10.1126/sciadv.adh9444">study</a>, published today in Science Advances, shows plants might take up more CO₂ than previously thought. </p>
<p>We found climate modelling that best accounted for the processes that sustain plant life consistently predicted the strongest CO₂ uptake. The most complex model predicted up to 20% more than the simplest version. </p>
<p>Our findings highlight the resilience of plants, and the importance of planting trees and preserving existing vegetation to slow climate change. While this is good news, it doesn’t let us off the hook in the fight against climate change. The rapid increase in atmospheric CO₂ means we must still cut emissions.</p>
<figure class="align-center ">
<img alt="A person holds a small sapling ready to be planted in the soli with a spade and trees in the background" src="https://images.theconversation.com/files/560100/original/file-20231117-17-cjovq1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/560100/original/file-20231117-17-cjovq1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/560100/original/file-20231117-17-cjovq1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/560100/original/file-20231117-17-cjovq1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/560100/original/file-20231117-17-cjovq1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/560100/original/file-20231117-17-cjovq1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/560100/original/file-20231117-17-cjovq1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Mass tree planting can help slow climate change but won’t on its own keep warming within acceptable limits.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/new-life-81582967">EduardSV/Shutterstock</a></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/carbon-budget-for-1-5-c-will-run-out-in-six-years-at-current-emissions-levels-new-research-216459">Carbon budget for 1.5°C will run out in six years at current emissions levels – new research</a>
</strong>
</em>
</p>
<hr>
<h2>What happens to the CO₂ plants take up?</h2>
<p>Plants take up CO₂ through photosynthesis. This process uses the Sun’s energy to convert – or “fix” – CO₂ from the air into the sugars plants use for growth and metabolic activity. </p>
<p>Plants release around half of that CO₂ back to the atmosphere via respiration relatively quickly. The other half is used for growth and stays in the plant biomass for longer – months to centuries. </p>
<p>That biomass will eventually die and decompose. Part of the carbon will be released again to the atmosphere, but other parts will enter the soil where it can stay for hundreds of years. </p>
<p>So, if plants take up more CO₂, it’s likely more carbon will be stored in vegetation and soils. This “land sink” of carbon has indeed increased over the past few decades as the <a href="https://essd.copernicus.org/articles/14/4811/2022/">annual global carbon budget assessment</a> has shown. </p>
<p>What’s more, the increasing land carbon sink has largely been attributed to the <a href="https://www.pnas.org/doi/10.1073/pnas.1407302112">beneficial effects of rising atmospheric CO₂ on plant photosynthesis</a>. This is important because that carbon stored in plants and soils slows the increase in atmospheric CO₂ and therefore global warming. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/560090/original/file-20231116-21-zi2n16.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Three line graphs showing the rate of increase in atmospheric CO2 and the extent of the land sink and ocean sink" src="https://images.theconversation.com/files/560090/original/file-20231116-21-zi2n16.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/560090/original/file-20231116-21-zi2n16.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=223&fit=crop&dpr=1 600w, https://images.theconversation.com/files/560090/original/file-20231116-21-zi2n16.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=223&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/560090/original/file-20231116-21-zi2n16.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=223&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/560090/original/file-20231116-21-zi2n16.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=280&fit=crop&dpr=1 754w, https://images.theconversation.com/files/560090/original/file-20231116-21-zi2n16.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=280&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/560090/original/file-20231116-21-zi2n16.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=280&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Main components of the global carbon cycle, showing the rate of increase in atmospheric CO₂ and the extent of the land sink and ocean sink.</span>
<span class="attribution"><a class="source" href="https://www.globalcarbonproject.org/carbonbudget/">Global Carbon Project 2022</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/in-20-years-of-studying-how-ecosystems-absorb-carbon-heres-why-were-worried-about-a-tipping-point-of-collapse-179554">In 20 years of studying how ecosystems absorb carbon, here's why we're worried about a tipping point of collapse</a>
</strong>
</em>
</p>
<hr>
<h2>A gap in current climate models</h2>
<p>But how do we know how much carbon is taken up and stored on land? Even more challenging, how can we predict what happens in the future? </p>
<p>One attempt to answer these questions is to use so-called terrestrial biosphere models. These models encapsulate our understanding of how plants function and how they respond to changes in climate. </p>
<p>For example, we know from experiments that plants <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/j.1365-3040.2007.01641.x">photosynthesise more under higher CO₂ concentrations</a> but <a href="https://academic.oup.com/jxb/article/62/3/869/478813">less when they don’t have enough water</a>. Models translate all this knowledge into mathematical equations and allow them to interact with each other. </p>
<p><em>All</em> this knowledge? Well, not really, and that was the motivation for our research. While today’s terrestrial biosphere models include <a href="https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2018MS001453">a plethora of processes</a>, they do not necessarily account for all mechanisms and processes that we know exist. There might not be enough data or information available to confidently represent a process across the entire globe, or it might just be difficult – conceptually or technically – to include it in models. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1359095003763589122"}"></div></p>
<h2>What did the study look at?</h2>
<p>We included three of those neglected processes into the well-established <a href="https://gmd.copernicus.org/articles/11/2995/2018/">Australian terrestrial biosphere model</a>. We accounted for:</p>
<ol>
<li>how efficiently CO₂ can move inside the leaf</li>
<li>how plants adjust to changes in their surrounding temperature</li>
<li>how they distribute nutrients most economically. </li>
</ol>
<p>We used the most recent data and research publications to include the processes as realistically as possible. We then confronted the model with a <a href="https://www.carbonbrief.org/explainer-the-high-emissions-rcp8-5-global-warming-scenario/">strong climate change scenario</a> and looked at how much CO₂ plants will take up until the end of this century. </p>
<p>We repeated this experiment with eight different versions of the model. The simplest version did not account for any of the three physiological mechanisms. The most complex version accounted for all three. </p>
<p>The results were surprisingly clear: the more complex the model, the higher the predicted CO₂ uptake by plants. Model versions that accounted for at least two mechanisms (those with greater ecological realism) consistently predicted the strongest CO₂ uptake – up to 20% more than the simplest version. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/no-more-excuses-restoring-nature-is-not-a-silver-bullet-for-global-warming-we-must-cut-emissions-outright-186048">No more excuses: restoring nature is not a silver bullet for global warming, we must cut emissions outright</a>
</strong>
</em>
</p>
<hr>
<h2>What does this mean for climate action?</h2>
<p>For modellers this is important news. It tells us our current models, which are usually at the lower end of this complexity range, likely underestimate future CO₂ uptake by plants.</p>
<p>These results suggest plants could be pretty resilient to even severe climate change. </p>
<p>However, we only looked at this from a plant physiological angle. Other processes in models are still oversimplified, such as the impacts of, and recovery from, fires and droughts. We clearly need to better capture these processes to get a more complete picture of how effectively plants will absorb CO₂ in the future. </p>
<p>And last but not least, because plants help fight climate change, it’s essential to conserve existing plant biomass and restore lost vegetation. </p>
<p>But while plants might even be more industrious helpers than previously assumed, they will never do the heavy lifting for us. It is still up to us humans to fight climate change by drastically cutting fossil fuel emissions. There is no shortcut.</p><img src="https://counter.theconversation.com/content/217786/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jürgen Knauer does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Climate modelling that best accounts for the processes that sustain plant life predicts plants could absorb up to 20% more CO₂ than the simplest version predicted.Jürgen Knauer, Postdoctoral Research Fellow, Hawkesbury Institute for the Environment, Western Sydney UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2163722023-11-16T10:12:57Z2023-11-16T10:12:57ZInsects are spreading a devastating plant disease in Italy – Britain must keep it out<figure><img src="https://images.theconversation.com/files/559575/original/file-20231115-27-9hc0jy.jpg?ixlib=rb-1.1.0&rect=0%2C486%2C3954%2C2134&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Olive trees that have died after becoming infected with _Xylella fastidiosa_.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/dead-olive-trees-xylella-fastidiosa-1471805759">Fabio Michele Capelli/Shutterstock</a></span></figcaption></figure><p>Since 2013, over 20 million olive trees in Italy have succumbed to a <a href="https://www.bbc.com/future/article/20230111-the-super-sniffer-dogs-saving-italys-dying-olive-trees#:%7E:text=With%20its%2060%20million%20olive,which%20were%20several%20centuries%20old">devastating plant disease</a>. The same disease now threatens many more plant species, across several countries, with the same fate. </p>
<p>Our recent <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0291734">research</a> shows that the insect responsible for inadvertently transmitting the bacteria that cause this disease can feed on a vast number of different plant species. These include many herbaceous plants and trees that are commonly grown in gardens, parks and across the wider countryside in Britain.</p>
<p>During spring, gardeners will often wonder why blobs of spit-like foam have suddenly appeared on their favourite plants. Many will think them unsightly, perhaps even taking time to wash them off, only for the foam to appear again the next day. </p>
<p>This “spittle” is produced by an insect, unimaginatively called a spittlebug, whose juvenile stages immerse themselves in the foam in order to stop drying out and to protect themselves from predators.</p>
<figure class="align-center ">
<img alt="Meadow spittlebug spittle on the branches of Salix." src="https://images.theconversation.com/files/559572/original/file-20231115-23-8e67h5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/559572/original/file-20231115-23-8e67h5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/559572/original/file-20231115-23-8e67h5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/559572/original/file-20231115-23-8e67h5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/559572/original/file-20231115-23-8e67h5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/559572/original/file-20231115-23-8e67h5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/559572/original/file-20231115-23-8e67h5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Spittle produced by a spittlebug.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/aphrophoridae-spittlebugs-family-insects-belonging-order-2000372249">Ihor Hvozdetskyi/Shutterstock</a></span>
</figcaption>
</figure>
<p>There are several species of spittlebug. But one in particular has been shown to smash several entomological records.</p>
<p>The <a href="https://en.wikipedia.org/wiki/Philaenus_spumarius">meadow spittlebug</a> (<em>Philaenus spumarius</em>) can jump with such force that it accelerates faster than any other animal, equivalent to an extraordinary <a href="https://journals.biologists.com/jeb/article/209/23/4607/16474/Jumping-performance-of-froghopper-insects">550 times</a> that of the Earth’s gravity. Even the toughest astronaut will die if faced with an acceleration <a href="https://www.sciencefocus.com/science/whats-the-maximum-speed-a-human-can-withstand">more than eight times</a> that of gravity.</p>
<p>These insects feed by sucking the sap out of plants. A typical adult meadow spittlebug will drink in and then excrete up to <a href="https://www.nytimes.com/2019/02/19/science/spittlebugs-bubble-home.html">200 times its body weight</a> of fluid per day: another record, and the equivalent of an average human excreting 13,000 litres each day. </p>
<p>Most recently, our research has found that this insect has far broader tastes than any other insect known to science; it can feed on over 1,300 species of plant.</p>
<h2>Why does this matter?</h2>
<p>The meadow spittlebug can transmit a bacterium called <em>Xylella fastidiosa</em> that is potentially deadly for the plants on which it feeds. When the spittlebug uses its syringe-like mouthparts to suck out the plant’s sap, the bacteria can get into the tubes that draw fluids up from the roots. Once there, the bacteria proliferate and block these tubes, starving the plant of water. </p>
<p>The symptoms of infection include scorched or stunted leaves. But, as these symptoms can be confused with several other plant problems, such as dehydration, a definitive diagnosis is difficult. To complicate matters further, some infected plants do not show any symptoms, at least not immediately, making them undetected reservoirs of the bacteria.</p>
<p>The bacteria have caused problems on an epic scale in <a href="https://apsjournals.apsnet.org/doi/epdf/10.1094/PHYTO-08-18-0319-FI">Apulia</a>, Italy’s premier olive-growing region. Entire groves of ancient olive trees have died or have been deliberately destroyed to stop the spread of this devastating plant disease.</p>
<p>The <a href="https://food.ec.europa.eu/plants/plant-health-and-biosecurity/legislation/control-measures/xylella-fastidiosa/database-susceptible-host-plants_en">list of plant species</a> that are known to be susceptible to this disease is long and growing. It already includes 690 species across 88 plant families, encompassing not just trees, but many popular garden plants, important horticultural crops and even some arable crops.</p>
<h2>Spittlebugs in Britain</h2>
<p>As part of our research, we asked members of the British public to send us their sightings of spittle. We received over 17,000 responses. Our results suggest that the insect is widespread in almost all British habitats, including gardens, and on an enormously diverse range of plants.</p>
<p>Fortunately, Britain and most of northern Europe are not yet in the grip of this plant disease. But the ubiquitous distribution of the spittlebug vector and its fondness for such a variety of different plants means that if the bacteria were ever accidentally introduced to Britain, it would be able to spread rapidly with potentially devastating consequences.</p>
<p>Scientists in Britain are anxiously watching for signs of any northward spread of the disease on the European continent. It originated in the Americas and was first detected in Apulia, Italy, in 2013, but it has since been <a href="https://www.efsa.europa.eu/en/topics/topic/xylella-fastidiosa#:%7E:text=Official%20surveys%20carried%20out%20by,How%20do%20plants%20become%20infected%3F">reported</a> in southern France, Spain and Portugal. Certain strains of the disease could certainly tolerate cooler northern temperatures, and their spread may be facilitated by our warming climate. </p>
<p><strong>The global distribution of <em>Xylella fastidiosa</em></strong></p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/559561/original/file-20231115-19-64hcev.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A world map showing the distribution of xylella fastidiosa bacteria." src="https://images.theconversation.com/files/559561/original/file-20231115-19-64hcev.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/559561/original/file-20231115-19-64hcev.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=301&fit=crop&dpr=1 600w, https://images.theconversation.com/files/559561/original/file-20231115-19-64hcev.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=301&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/559561/original/file-20231115-19-64hcev.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=301&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/559561/original/file-20231115-19-64hcev.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=378&fit=crop&dpr=1 754w, https://images.theconversation.com/files/559561/original/file-20231115-19-64hcev.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=378&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/559561/original/file-20231115-19-64hcev.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=378&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Xylella fastidiosa has not yet been detected in Britain.</span>
<span class="attribution"><a class="source" href="https://gd.eppo.int/taxon/XYLEFA/distribution">EPPO Global Database</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/">CC BY-NC-SA</a></span>
</figcaption>
</figure>
<h2>Stopping the spread</h2>
<p>Spittlebugs don’t fly very far so are unlikely to bring the disease into Britain themselves. The most likely entry route would be through plants brought in via the horticultural trade. </p>
<p>Historically, Britain has imported both lavender and olive trees from Italy. However, these plants now have to go through strict importation and quarantine <a href="https://planthealthportal.defra.gov.uk/assets/uploads/UK-Trade-Letter-Feb21-.pdf">controls</a>.</p>
<p>It is critically important that British holidaymakers in Mediterranean countries do not bring home live plant material of any kind. <em>Xylella fastidiosa</em> has not been detected in Britain so far, but the spittlebug’s extraordinarily broad taste in food shows that it would be extremely hard to control if it ever did arrive.</p>
<hr>
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<img alt="Imagine weekly climate newsletter" src="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/434988/original/file-20211201-21-13avx6y.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
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<p><strong><em>Don’t have time to read about climate change as much as you’d like?</em></strong>
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<hr><img src="https://counter.theconversation.com/content/216372/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Alan Stewart received funding from the UK Biotechnology and Biological Sciences Research Council.</span></em></p><p class="fine-print"><em><span>Claire Harkin received funding from the UK Biotechnology and Biological Sciences Research Council</span></em></p><p class="fine-print"><em><span>Vinton Thompson receives funding from the Biotechnology and Biological Sciences Research Council. </span></em></p>The meadow spittlebug can transmit a deadly bacterium – many plants in Britain could be at risk.Alan Stewart, Professor of Ecology, University of SussexClaire Harkin, Research Associate in the Department of Evolution, Behaviour and Environment, University of SussexVinton Thompson, Research Associate in the Division of Invertebrate Zoology, American Museum of Natural HistoryLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2169532023-11-09T13:34:54Z2023-11-09T13:34:54ZExposing plants to an unusual chemical early on may bolster their growth and help feed the world<figure><img src="https://images.theconversation.com/files/558170/original/file-20231107-15-2x75fz.jpg?ixlib=rb-1.1.0&rect=69%2C0%2C5106%2C3445&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">'Priming' plants by exposing them to certain chemicals while they're seeds can affect their growth later in life. </span> <span class="attribution"><a class="source" href="https://newsroom.ap.org/detail/EbolaPlantMedicines/4e55603d42934e59bf03858de1aae0db/photo?Query=plants&mediaType=photo&sortBy=&dateRange=Anytime&totalCount=222&currentItemNo=30&vs=true&vs=true">AP Photo/Gerry Broome</a></span></figcaption></figure><p>Just like any other organism, plants can get stressed. Usually it’s conditions like <a href="https://theconversation.com/crops-could-face-double-trouble-from-insects-and-a-warming-climate-131367">heat and drought</a> that lead to this stress, and when they’re stressed, plants might not grow as large or produce as much. This can be a problem for farmers, so many scientists have tried <a href="https://theconversation.com/can-gene-editing-provide-a-solution-to-global-hunger-43444">genetically modifying plants</a> to be more resilient. </p>
<p>But plants modified for higher crop yields tend to have <a href="https://doi.org/10.3390/plants11010033">a lower stress tolerance</a> because they put more energy into growth than into protection against stresses. Similarly, improving the ability of plants to survive stress often results in plants that produce less because they put more energy into protection than into growth. This conundrum makes it <a href="https://doi.org/10.1016/j.biori.2020.02.001">difficult to improve crop production</a>.</p>
<p><a href="http://binderlab.utk.edu/">I have been studying</a> how the plant hormone ethylene regulates growth and stress responses in plants. In a <a href="https://doi.org/10.1093/pnasnexus/pgad216">study published in July 2023</a>, my lab made an unexpected and exciting observation. We found that when seeds are germinating in darkness, as they usually are underground, adding ethylene can increase both their growth and stress tolerance.</p>
<h2>Ethylene is a plant hormone</h2>
<p>Plants can’t move around, so they can’t avoid stressful environmental conditions like heat and drought. They take in a variety of signals from their environment such as light and temperature that shape how they grow, develop and deal with stressful conditions. As part of this regulation, plants <a href="https://www.sciencedirect.com/topics/neuroscience/plant-hormone">make various hormones</a> that are part of a regulatory network that allows them to adapt to environmental conditions. </p>
<p><a href="https://www.sciencedirect.com/topics/pharmacology-toxicology-and-pharmaceutical-science/ethylene">Ethylene</a> was first discovered as a gaseous plant hormone <a href="https://doi.org/10.1007/s00344-015-9522-9">over 100 years ago</a>. Since then, research has shown that all land plants that have been studied make ethylene. In addition to controlling growth and responding to stress, it is also involved in other processes such as causing leaves to change color in the fall and stimulating fruit ripening. </p>
<h2>Ethylene as a way to ‘prime’ plants</h2>
<p>My lab focuses on how plants and bacteria sense ethylene and on how it interacts with other hormone pathways to regulate plant development. While conducting this research, my group made <a href="https://doi.org/10.1093/pnasnexus/pgad216">an accidental discovery</a>.</p>
<p>We’d been running an experiment where we had seeds germinating in a dark room. Seed germination is a critical period in a plant’s life when, under favorable conditions, the seed will transition from being dormant into a seedling. </p>
<p>For this experiment, we’d <a href="https://doi.org/10.1093/pnasnexus/pgad216">exposed the seeds to ethylene gas</a> for several days to see what effect this might have. We’d then removed the ethylene. Normally, this is where the experiment would have ended. But after gathering data on these seedlings, we transferred them to a light cart. This is not something we usually do, but we wanted to grow the plants to adulthood so we could get seeds for future experiments.</p>
<p>Several days after placing the seedlings under light, some lab members made the unexpected and startling observation that the plants briefly gassed with ethylene <a href="https://doi.org/10.1093/pnasnexus/pgad216">were much larger</a>. They had larger leaves as well as longer and more complex root systems than plants that had not been exposed to ethylene. These plants continued growing at a faster rate throughout their whole lifetime. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/557339/original/file-20231102-26-1tp153.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Two plants as shown from above on a black table. The plant on the left is smaller than the plant on the right." src="https://images.theconversation.com/files/557339/original/file-20231102-26-1tp153.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/557339/original/file-20231102-26-1tp153.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=358&fit=crop&dpr=1 600w, https://images.theconversation.com/files/557339/original/file-20231102-26-1tp153.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=358&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/557339/original/file-20231102-26-1tp153.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=358&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/557339/original/file-20231102-26-1tp153.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=450&fit=crop&dpr=1 754w, https://images.theconversation.com/files/557339/original/file-20231102-26-1tp153.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=450&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/557339/original/file-20231102-26-1tp153.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=450&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The plant on the left was not primed with ethylene, while the plant on the right was. Both plants are the same age.</span>
<span class="attribution"><span class="source">Binder lab, University of Tennessee, Knoxville</span></span>
</figcaption>
</figure>
<p>My colleagues and I wanted to know if diverse plant species showed growth stimulation when exposed to ethylene during seed germination. We found that <a href="https://doi.org/10.1093/pnasnexus/pgad216">the answer is yes</a>. We tested the effects of short-term ethylene treatment on germinating tomato, cucumber, wheat and arugula seeds – all grew bigger.</p>
<p>But what made this observation unusual and exciting is that the brief ethylene treatment also <a href="https://doi.org/10.1093/pnasnexus/pgad216">increased tolerance to various stresses</a> such as salt stress, high temperature and low oxygen conditions. </p>
<p>Long-term effects on growth and stress tolerance from brief exposure to a stimulus are often called priming effects. You can think of this much like <a href="https://chemicalengineeringworld.com/what-is-pump-priming/">priming a pump</a>, where the priming helps get the pump started easier and sooner. <a href="https://doi.org/10.1111/ppl.13881">Studies have looked at how plants grow after priming</a> at various ages and stages of development. But <a href="https://doi.org/10.1111/ppl.13881">seed priming</a> with various chemicals and stresses has probably been the most studied because it is easy to carry out, and, if successful, it can be used by farmers. </p>
<h2>How does it work?</h2>
<p>Since <a href="https://scienmag.com/ethylene-boosts-plant-yield-and-vigor/">that first experiment</a>, my lab group has tried to figure out what mechanisms allow for these ethylene-exposed plants to grow larger and tolerate more stress. We’ve found a few potential explanations.</p>
<p>One is that ethylene priming increases photosynthesis, the process plants use to make sugars from light. Part of photosynthesis includes what is called <a href="https://www.biologyonline.com/dictionary/carbon-fixation">carbon fixation</a>, where plants take CO₂ from the atmosphere and use the CO₂ molecules as the building blocks to make the sugars. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/CL9A8YhwUps?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">During photosynthesis and carbon fixation, plants take in sunlight and convert it into the sugars that they use to grow.</span></figcaption>
</figure>
<p>My lab group showed that there is a large increase in carbon fixation – which means the plants are taking in much more CO₂ from the atmosphere.</p>
<p>Correlating with the increase in photosynthesis is a large increase in carbohydrate levels throughout the plant. This includes large increases <a href="https://doi.org/10.1016/j.plantsci.2022.111223">in starch</a>, which is the energy storage molecule in plants, and two sugars, <a href="https://doi.org/10.1146/annurev-arplant-050213-040251">sucrose</a> and <a href="https://sciencing.com/what-is-glucose-used-for-in-a-plant-13428304.html">glucose</a>, that provide quick energy for the plants. </p>
<p>More of these molecules in the plant has been linked to both <a href="https://doi.org/10.1111/ppl.13656">increased growth</a> and a better ability for plants to <a href="https://doi.org/10.1016/B978-0-12-813066-7.00002-4">withstand stressful conditions</a>.</p>
<p><a href="https://doi.org/10.1093/pnasnexus/pgad216">Our study</a> shows that environmental conditions during germination can have profound and long-lasting effects on plants that could increase both their size and their stress tolerance at the same time. Understanding the mechanisms for this is more important than ever and could help improve crop production to feed the world’s population.</p><img src="https://counter.theconversation.com/content/216953/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Brad Binder receives funding from the U.S. National Science Foundation.</span></em></p>A research accident in the Binder lab at the University of Tennessee led to an unprecedented discovery about how plants respond to a hormone called ethylene.Brad Binder, Professor of Biochemistry & Cellular and Molecular Biology, University of TennesseeLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2138842023-10-19T13:18:57Z2023-10-19T13:18:57ZNamibia and Angola’s remote Ovahimba mountains reveal a haven for unique plants – new survey<p>The Kaokoveld region, covering north-western Namibia and south-western Angola, is one of the remotest areas in southern Africa. Although it’s extremely dry, it is a centre of species endemism: many species occur only there and nowhere else on earth. </p>
<p>New species continue to be found, especially in the Ovahimba mountain range, which runs parallel to the cold Atlantic ocean and is separated from it by the gravel plains and dunes of the northern Namib Desert.</p>
<p>The highest mountain peaks of this range are so inhospitable and difficult to access, because of the lack of roads and water, that few have ever scaled them. The exceptions are local herders of the semi-nomadic <a href="https://www.lcfn.info/ovahimba/information/ethnology">Himba</a>, who drive their cattle and goats to richer pastures in the mountains during dry periods. </p>
<p>In 2021, I was part of a team of researchers from Namibia and Angola who aimed to investigate the biodiversity and endemism on some of the most remote peaks. We hypothesised that the mountain peaks harboured a large number of species, especially plants, insects and reptiles. That’s because there’s a rapid change in climate and topography (land features) from the hyper-arid, cool desert near the coast and the arid and seasonally warmer plains further inland to the cooler mountainous escarpment. </p>
<p>Through an EU-funded transfrontier conservation <a href="http://sciona.nust.na/">project, SCIONA</a>, we had the opportunity to use the only safe option to get to the Ovahimba mountain peaks: a helicopter.</p>
<p>It is incredibly exciting to plan a trip to such a remote and beautiful wilderness area where few people have intervened in the ecosystem. </p>
<p>Because of the high cost and complicated logistics, we had to limit <a href="https://conservationnamibia.com/pdfs/cn2021-helicopter-science.pdf">the visit</a> to a few days on each of three mountain tops. Two were in Angola – Serra Cafema and Serra Tchamalindi in <a href="https://www.africanparks.org/the-parks/iona">Iona National Park</a> – and one was in the Otjihipa range of Namibia. The mountain tops were selected based on their altitude and remoteness. They also have many ecological niches based on exposure to wind and sun. </p>
<p>At each campsite, we left excitedly in different directions, to return and exchange findings and stories after sunset.</p>
<p>Even in this short visit, we <a href="https://www.tandfonline.com/doi/full/10.1080/0035919X.2023.2211040">found</a> plenty of interest and some surprises. Of the 285 plant species we encountered, 34 species are endemic to the Kaokoveld. One is new to science and at least six endemics fall in the endangered <a href="https://www.iucnredlist.org/">IUCN red list</a> category. Sixteen plant species that were previously known only from Namibia were found in Angola. We also <a href="https://www.researchgate.net/publication/374413378_First_records_for_Angola_of_Cape_Eagle_Owl_and_Layard's_Warbler">recorded</a> two bird species, the Cape Eagle Owl and Layard’s Warbler, in Angola for the first time. </p>
<p>These mountain flora deserve priority conservation efforts to protect endemic and other plants that have survived in these refuge sites, providing a habitat for some unique fauna.</p>
<h2>Helicopter adventure</h2>
<p>Our helicopter hops between the mountains gave us unforgettable, magnificent views of the mountains, through which the glittering Kunene River meanders. The first campsite was in the Otjihipa range, at a mountain that we named Middelberg (1,941 metres above sea level).</p>
<p>The ridge boasts a diverse shrub and woodland vegetation, unlike the barren plains surrounding it, because of the cooler temperatures, the water bearing capacities of rocks, less grazing and browsing, and what we assume is higher rainfall (there are no records). It was adorned by beautiful Kaoko tree-euphorbias (<em>Euphorbia eduardoi</em>).</p>
<p>We also found a large underground cave with intact stalactite and stalagmite formations. This is unusual in the area and may indicate that there was much more water there in the past. </p>
<p>The second campsite was near a mountain top in the eastern part of the large Tchamalinde range, at an elevation of 1,420 metres above sea level. The helicopter could not land higher up the mountain where it was covered with a continuous tree layer. The Kaokoveld endemic flower <em>Turnera oculata var. paucipilosa</em> thrives in this area, as well as the resurrection bush (<em>Myrothamnus flabellifolius</em>) and the black stick lily (<em>Xerophyta retinervis</em>). Resurrection plants appear to be dead during the dry season but suddenly turn green with the rains.</p>
<p>Our last campsite was 100 metres from the top of the highest mountain of Iona National Park, Serra Cafema (2,050 metres above sea level). Of the three mountain tops we visited, it was the closest to the coast (85km) and therefore also the coldest and windiest.</p>
<p>Despite the harsh climate, there was a surprising amount of vegetation, mainly a mosaic of hardy <a href="https://pza.sanbi.org/vegetation/fynbos-biome">Cape fynbos</a>-like shrubs and dry savanna vegetation with large-stemmed Namib resin trees (<em>Ozoroa crassinervia</em>). It was a surprise to find the tall <em>Euphorbia monteiroi subsp. brandbergensis</em> as it was previously only known further south in Namibia. Another beautiful <em>Turnera</em> flower (<em>Turnera oculata var. oculata</em>) was common at Serra Cafema, as well as large specimens of mother-in-law’s-tongue (<em>Sansevieria pearsonii</em>).</p>
<p>Even on the mountain top of Serra Cafema, the highest and remotest of all, there were signs of human impact via grazing. </p>
<p>The findings show the highest plant biodiversity on Serra Cafema, with 56 species per 1,000m² compared to 47 species per 1,000m² for the other mountains. Of the three mountains, Serra Cafema is the most influenced by fog caused by the cold Benguela current. Species composition is very different from the surrounding lowlands.</p>
<h2>Protecting biodiversity</h2>
<p>We unlocked only a fraction of the mystery held by these biodiversity hotspots. There is no doubt that yet more unusual and interesting plants and animals are waiting to be discovered on these inaccessible peaks, especially because our visit took place after 10 years of drought. Huge swarms of <a href="https://theconversation.com/brown-locusts-have-survived-a-long-drought-in-south-africa-heres-how-158488">locusts</a> were in the barren plains at that time.</p>
<p>However, our reconnaissance survey did show that the plants here need protection. They are threatened by <a href="https://www.ipcc.ch/report/ar6/wg1/downloads/factsheets/IPCC_AR6_WGI_Regional_Fact_Sheet_Africa.pdf">climate change</a> and <a href="https://www.researchgate.net/publication/374413480_An_Integrated_Ecosystem_Management_Framework_for_the_Skeleton_Coast-Iona_Transfrontier_Park">overgrazing by livestock</a>. Management of the Ovahimba highlands is in the hands of Namibian communal conservancies, the NGO <a href="https://www.africanparks.org/">African Parks</a> and the Namibian and Angolan governments. African Parks recently took over management of <a href="https://www.africanparks.org/the-parks/iona">Iona National Park</a>, which may offer opportunities to protect the mountain habitats.</p><img src="https://counter.theconversation.com/content/213884/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Vera De Cauwer was Principal Investigator of the SCIONA project that received funding from
the European Union under grant agreement FED/2017/394-802.</span></em></p>Mountain flora in the Kaokoveld deserve priority conservation efforts.Vera De Cauwer, Associate Professor Natural Resource Management, Namibia University of Science and TechnologyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2152212023-10-17T09:24:28Z2023-10-17T09:24:28ZWhat 2,500 years of wildfire evidence and the extreme fire seasons of 1910 and 2020 tell us about the future of fire in the West<figure><img src="https://images.theconversation.com/files/553881/original/file-20231015-29-pxqkiy.jpg?ixlib=rb-1.1.0&rect=84%2C333%2C3611%2C2357&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Rocky Mountain fires leave telltale ash layers in nearby lakes like this one.</span> <span class="attribution"><span class="source">Philip Higuera</span></span></figcaption></figure><p>Strong winds blew across mountain slopes after a record-setting warm, dry summer. Small fires began to blow up into huge conflagrations. Towns in crisis scrambled to escape as fires bore down. </p>
<p>This could describe any number of recent events, in places as disparate as <a href="https://www.cpr.org/2021/01/25/colorados-east-troublesome-wildfire-may-signal-a-new-era-of-big-fire-blow-ups/">Colorado</a>, <a href="https://www.nist.gov/news-events/news/2021/02/new-timeline-deadliest-california-wildfire-could-guide-lifesaving-research">California</a>, <a href="https://www.cbc.ca/news/canada/british-columbia/bc-wildfires-june-30-2021-1.6085919">Canada</a> and <a href="https://www.washingtonpost.com/climate-environment/2023/08/13/maui-wildfire-started-spread/">Hawaii</a>. But this fire disaster happened over 110 years ago in the Northern Rocky Mountains of Idaho and Montana.</p>
<p>The “<a href="https://www.pbs.org/video/american-experience-big-burn/">Big Burn</a>” of 1910 still holds the record for the largest fire season in the Northern Rockies. Hundreds of fires burned over 3 million acres – roughly the size of Connecticut – most in just two days. The fires destroyed towns, killed 86 people and galvanized public policies committed to putting out every fire.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/553871/original/file-20231015-23-f0ar90.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A black and white photo from 1910 shows rail lines and the burned shells of buildings" src="https://images.theconversation.com/files/553871/original/file-20231015-23-f0ar90.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/553871/original/file-20231015-23-f0ar90.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=487&fit=crop&dpr=1 600w, https://images.theconversation.com/files/553871/original/file-20231015-23-f0ar90.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=487&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/553871/original/file-20231015-23-f0ar90.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=487&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/553871/original/file-20231015-23-f0ar90.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=612&fit=crop&dpr=1 754w, https://images.theconversation.com/files/553871/original/file-20231015-23-f0ar90.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=612&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/553871/original/file-20231015-23-f0ar90.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=612&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Many residents of Wallace, Idaho, fled on trains ahead of the 1910 blaze. Volunteers who stayed saved part of the town, but about a third of it burned.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/fsnorthernregion/4929826527/in/album-72157624814120716/">R.H. McKay/U.S. Forest Service archive</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Today, as the climate warms, fire seasons like in 1910 are becoming more likely. The <a href="https://doi.org/10.1111/gcb.15388">2020 fire season</a> was an example. But are extreme fire seasons like these really that unusual in the context of history? And, when fire activity begins to surpass anything experienced in thousands of years – as research suggests is happening in the Southern Rockies – what will happen to the forests?</p>
<p>As paleoecologists, we study how and why ecosystems changed in the past. In a multiyear project, highlighted in <a href="https://doi.org/10.1088/1748-9326/acee16">two new</a> <a href="https://doi.org/10.1111/1365-2745.14201">publications</a>, we tracked how often forest fires occurred in high-elevation forests in the Rocky Mountains over the past 2,500 years, how those fires varied with the climate and how they affected ecosystems. This long view provides both hopeful and concerning lessons for making sense of today’s extreme fire events and impacts on forests.</p>
<h2>Lakes record history going back millennia</h2>
<p>When a high-elevation forest burns, fires consume tree needles and small branches, killing most trees and lofting charcoal in the air. Some of that charcoal lands on lakes and sinks to the bottom, where it is preserved in layers as sediment accumulates. </p>
<p>After the fire, trees regrow and also leave evidence of their existence in the form of pollen grains that fall on the lake and sink to the bottom.</p>
<p>By <a href="https://www.youtube.com/watch?v=0DixyJZCvVQ">extracting a tube</a> of those lake sediments, like a straw pushed into a layer cake from above, we were able to measure the amounts of charcoal and pollen in each layer and reconstruct the history of fire and forest recovery around a dozen lakes across the footprint of the 1910 fires.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/553883/original/file-20231016-28-18q8gm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A woman sitting an inflatable boat, wearing a life jacket, holds a long tube filed with lake bottom sediment." src="https://images.theconversation.com/files/553883/original/file-20231016-28-18q8gm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/553883/original/file-20231016-28-18q8gm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=422&fit=crop&dpr=1 600w, https://images.theconversation.com/files/553883/original/file-20231016-28-18q8gm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=422&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/553883/original/file-20231016-28-18q8gm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=422&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/553883/original/file-20231016-28-18q8gm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=530&fit=crop&dpr=1 754w, https://images.theconversation.com/files/553883/original/file-20231016-28-18q8gm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=530&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/553883/original/file-20231016-28-18q8gm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=530&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Author Kyra Clark-Wolf holds a sediment core pulled from a lake containing evidence of fires over thousands of years.</span>
<span class="attribution"><span class="source">Philip Higuera</span></span>
</figcaption>
</figure>
<figure class="align-center ">
<img alt="Long tubes of lake floor sediment are opened on a table." src="https://images.theconversation.com/files/553888/original/file-20231016-26-18q8gm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/553888/original/file-20231016-26-18q8gm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/553888/original/file-20231016-26-18q8gm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/553888/original/file-20231016-26-18q8gm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/553888/original/file-20231016-26-18q8gm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/553888/original/file-20231016-26-18q8gm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/553888/original/file-20231016-26-18q8gm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Researchers at the University of Montana examine a sediment core from a high-elevation lake in the Rocky Mountains. Each core is sliced into half-centimeter sections, reflecting around 10 years each, and variations in charcoal within the core are used to reconstruct a timeline of past wildfires.</span>
<span class="attribution"><span class="source">University of Montana</span></span>
</figcaption>
</figure>
<h2>Lessons from Rockies’ long history with fire</h2>
<p>The <a href="https://doi.org/10.1111/1365-2745.14201">lake sediments revealed</a> that high-elevation, or subalpine, forests in the Northern Rockies in Montana and Idaho have consistently bounced back after fires, even during periods of <a href="https://doi.org/10.1017/qua.2022.17">drier climate</a> and more frequent burning than we saw in the 20th century.</p>
<p>High-elevation forests only burn about once <a href="https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/subalpine-forest">every 100 to 250 or more years</a> on average. <a href="https://doi.org/10.1088/1748-9326/acee16">We found</a> that the amount of burning in subalpine forests of the Northern Rockies over the 20th and 21st centuries remained within the bounds of what those forests experienced over the previous 2,500 years. Even today, the Northern Rockies <a href="https://doi.org/10.1016/j.foreco.2023.121283">show resilience to wildfires</a>, including <a href="https://doi.org/10.1016/j.foreco.2022.120487">early signs of recovery</a> after extensive fires <a href="https://doi.org/10.3390/fire1010017">in 2017</a>.</p>
<figure class="align-center ">
<img alt="Three illustrated charts show forest density increasing and time between fires falling over the past 4,800 years at one location." src="https://images.theconversation.com/files/554164/original/file-20231017-21-tsez5.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/554164/original/file-20231017-21-tsez5.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=769&fit=crop&dpr=1 600w, https://images.theconversation.com/files/554164/original/file-20231017-21-tsez5.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=769&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/554164/original/file-20231017-21-tsez5.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=769&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/554164/original/file-20231017-21-tsez5.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=966&fit=crop&dpr=1 754w, https://images.theconversation.com/files/554164/original/file-20231017-21-tsez5.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=966&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/554164/original/file-20231017-21-tsez5.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=966&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Long-term changes in climate, forest density and fire frequency over the past 4,800 years in one high-elevation forest in the Northern Rockies, reconstructed from lake sediments. The red dots reflect timing of past fires.</span>
<span class="attribution"><span class="source">Kyra Clark-Wolf</span></span>
</figcaption>
</figure>
<p>But <a href="https://doi.org/10.1073/pnas.2103135118">similar research</a> in high-elevation forests of the Southern Rockies in Colorado and Wyoming tells a different story.</p>
<p>The record-setting 2020 fire season, with <a href="https://dfpc.colorado.gov/sections/wildfire-information-center/historical-wildfire-information">three of Colorado’s largest fires</a>, helped push the rate of burning in high-elevation forests in Colorado and Wyoming into <a href="https://theconversation.com/rocky-mountain-forests-burning-more-now-than-any-time-in-the-past-2-000-years-162383">uncharted territory</a> relative to the past 2,000 years.</p>
<p>Climate change is also having bigger impacts on <a href="https://theconversation.com/the-wests-iconic-forests-are-increasingly-struggling-to-recover-from-wildfires-altering-how-fires-burn-could-boost-their-chances-200668">whether and how forests recover after wildfires</a> in warmer, drier regions of the West, including the <a href="https://doi.org/10.1111/geb.13174">Southern Rockies</a>, the <a href="https://doi.org/10.1073/pnas.2208120120">Southwest and California</a>. When fires are followed by especially warm, dry summers, seedlings can’t establish and forests struggle to regenerate. In some places, shrubby or grassy vegetation replace trees altogether.</p>
<figure class="align-center ">
<img alt="Graphs show fire activity rising with temperature over time." src="https://images.theconversation.com/files/553861/original/file-20231015-29-f0ar90.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/553861/original/file-20231015-29-f0ar90.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=359&fit=crop&dpr=1 600w, https://images.theconversation.com/files/553861/original/file-20231015-29-f0ar90.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=359&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/553861/original/file-20231015-29-f0ar90.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=359&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/553861/original/file-20231015-29-f0ar90.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=451&fit=crop&dpr=1 754w, https://images.theconversation.com/files/553861/original/file-20231015-29-f0ar90.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=451&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/553861/original/file-20231015-29-f0ar90.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=451&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Fire history reconstructions from 20 high-elevation lakes in the Southern Rockies show that historically, fires burned every 230 years on average. That has increased significantly in the 21st century.</span>
<span class="attribution"><a class="source" href="https://theconversation.com/rocky-mountain-forests-burning-more-now-than-any-time-in-the-past-2-000-years-162383">Philip Higuera</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Changes happening now in the Southern Rockies could serve as an early warning for what to expect further down the road in the Northern Rockies.</p>
<h2>Warmer climate, greater fire activity, higher risks</h2>
<p>Looking back thousands of years, it’s hard to ignore the consistent links between the climate and the prevalence of wildfires.</p>
<p>Warmer, drier springs and summers <a href="https://doi.org/10.1038/s43247-021-00299-0">load the dice</a> to make extensive fire seasons more likely. This was the case <a href="https://doi.org/10.1371/journal.pone.0127563">in 1910</a> in the Northern Rockies and <a href="https://doi.org/10.1111/gcb.15388">in 2020</a> in the Southern Rockies. </p>
<p>When, where and how climate change will push the rate of burning in the rest of the Rockies into uncharted territory is harder to anticipate. The difference between 1910 and 2020 was that 1910 was followed by decades with low fire activity, whereas 2020 was part of an overall trend of increasing fire activity linked with global warming. Just one fire like 1910’s Big Burn in the coming decades, in the context of 21st-century fire activity, would push the Northern Rockies beyond any known records.</p>
<figure class="align-center ">
<img alt="A tiny pine seedling in a vast landscape of burned trees and soil." src="https://images.theconversation.com/files/554092/original/file-20231016-21-sz8p4c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/554092/original/file-20231016-21-sz8p4c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=801&fit=crop&dpr=1 600w, https://images.theconversation.com/files/554092/original/file-20231016-21-sz8p4c.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=801&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/554092/original/file-20231016-21-sz8p4c.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=801&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/554092/original/file-20231016-21-sz8p4c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1006&fit=crop&dpr=1 754w, https://images.theconversation.com/files/554092/original/file-20231016-21-sz8p4c.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1006&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/554092/original/file-20231016-21-sz8p4c.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1006&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A lodgepole pine tree seedling begins to grow one year after the October 2020 East Troublesome Fire in Rocky Mountain National Park. Recovery in high-elevation forests takes decades.</span>
<span class="attribution"><span class="source">Philip Higuera</span></span>
</figcaption>
</figure>
<h2>Lessons from the long view</h2>
<p>The clock is ticking. </p>
<p><a href="https://doi.org/10.1111/geb.13496">Extreme wildfires will become more and more likely</a> as the climate warms, and it will be <a href="https://theconversation.com/the-wests-iconic-forests-are-increasingly-struggling-to-recover-from-wildfires-altering-how-fires-burn-could-boost-their-chances-200668">harder for forests to recover</a>. Human activity is also raising the risk of fires starting.</p>
<p>The Big Burn of 1910 left a lasting impression because of the devastating impacts on lives and homes and, <a href="https://www.coloradoan.com/story/news/2022/06/03/east-troublesome-fire-cause-colorado-arapaho-national-forest/7506191001/">as in the 2020 fire season</a> and many other recent fire disasters, because of the <a href="https://doi.org/10.1093/pnasnexus/pgad005">role humans played</a> in igniting them.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/553876/original/file-20231015-25-m2xrcy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Photo shows burned trees across miles of hillsides along a railroad line" src="https://images.theconversation.com/files/553876/original/file-20231015-25-m2xrcy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/553876/original/file-20231015-25-m2xrcy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=479&fit=crop&dpr=1 600w, https://images.theconversation.com/files/553876/original/file-20231015-25-m2xrcy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=479&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/553876/original/file-20231015-25-m2xrcy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=479&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/553876/original/file-20231015-25-m2xrcy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=602&fit=crop&dpr=1 754w, https://images.theconversation.com/files/553876/original/file-20231015-25-m2xrcy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=602&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/553876/original/file-20231015-25-m2xrcy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=602&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The aftermath of the 1910 fire near the North Fork of the St. Joe River in the Coeur d’Alene National Forest, Idaho.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/fsnorthernregion/4929815653/in/album-72157624814120716/">R.H. McCoy/U.S. Forest Service archive</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Accidental ignitions – from downed power lines, escaped campfires, dragging chains, railroads – expand <a href="https://doi.org/10.1073/pnas.1617394114">when and where fires occur</a>, and <a href="https://theconversation.com/western-wildfires-destroyed-246-more-homes-and-buildings-over-the-past-decade-fire-scientists-explain-whats-changing-197384">they lead to the majority of homes lost to fires</a>. The fire that <a href="https://www.cnn.com/2023/08/11/business/maui-fire-residential-damage-preliminary-estimate/index.html">destroyed Lahaina, Hawaii</a>, is the most recent example.</p>
<h2>So what can we do?</h2>
<p><a href="https://www.unep.org/interactive/six-sector-solution-climate-change/">Curbing greenhouse gas emissions</a> from vehicles, power plants and other sources can help slow warming and the impacts of climate change on wildfires, ecosystems and communities. <a href="https://theconversation.com/the-us-is-spending-billions-to-reduce-forest-fire-risks-we-mapped-the-hot-spots-where-treatment-offers-the-biggest-payoff-for-people-and-climate-210051">Forest thinning and prescribed burns</a> can <a href="https://doi.org/10.1002/eap.2433">alter how forests burn</a>, protecting humans and <a href="https://theconversation.com/the-wests-iconic-forests-are-increasingly-struggling-to-recover-from-wildfires-altering-how-fires-burn-could-boost-their-chances-200668">minimizing the most severe ecological impacts</a>.</p>
<p><a href="https://doi.org/10.1088/1748-9326/ac5c0c">Reframing the challenge of living with wildfire</a> – building with fire-resistant materials, reducing accidental ignitions and increasing preparedness for extreme events – can <a href="https://theconversation.com/well-see-more-fire-seasons-like-2020-heres-a-strategy-for-managing-our-nations-flammable-landscapes-149323">help minimize damage</a> while maintaining the critical role that fires have played in forests across the Rocky Mountains for millennia.</p><img src="https://counter.theconversation.com/content/215221/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kyra Clark-Wolf has received funding from the National Science Foundation and the Joint Fire Science Program</span></em></p><p class="fine-print"><em><span>Philip Higuera receives funding from the National Science Foundation, United States Geological Survey, and Joint Fire Science Program.</span></em></p>As the climate warms, devastating fires are increasingly likely. The 2020 fires pushed the Southern Rockies beyond the historical average. Is there hope for the Northern Rockies?Kyra Clark-Wolf, Postdoctoral Associate in Ecology, University of Colorado BoulderPhilip Higuera, Professor of Fire Ecology, University of MontanaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2151032023-10-09T17:19:20Z2023-10-09T17:19:20ZWild plants may edit their genomes in the same way we make GM crops – and it could be crucial to evolution<figure><img src="https://images.theconversation.com/files/552485/original/file-20231006-25-tjh98j.jpg?ixlib=rb-1.1.0&rect=16%2C24%2C5447%2C3612&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/girl-runs-her-hand-over-tall-2017555694">zhukovvvlad/Shutterstock</a></span></figcaption></figure><p>Genetically modified (GM) crops may be controversial, but similar processes happen naturally with wild plants. However, scientists have long been puzzled about how these processes happen. Our <a href="https://nph.onlinelibrary.wiley.com/doi/10.1111/nph.19272">recent study</a> may help researchers solve the mystery. </p>
<p>People often use the “<a href="https://www.discoverwildlife.com/animal-facts/tree-of-life-evolution">tree of life</a>” as a metaphor to describe the evolutionary relationships between organisms. The more closely related species are, the closer together they appear in the tree.</p>
<p>This is a bit misleading though, as reality is more complicated. Species don’t always split off along their own evolutionary path in isolation from other branches. In fact, in some groups of organisms, connections among branches are so common that we may need to abandon the notion of a tree of life altogether. This is particularly true for bacteria, where the evolutionary relationships look more like a <a href="https://www.frontiersin.org/articles/10.3389/fcimb.2012.00113/full">tangled web than a tree</a>. The crosstalk between branches is caused by the movement of genetic information.</p>
<p><a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4536854/#:%7E:text=DEFINITION%20AND%20BACKGROUND,offspring">Horizontal gene transfer</a> (also known as lateral gene transfer) is the process by which pieces of DNA (such as genes) move between organisms outside of the usual parent to offspring route. It allows genetic information to be shared between distant branches of the tree of life without sexual reproduction, and it is responsible for the rapid spread of traits such as <a href="https://www.frontiersin.org/articles/10.3389/fmicb.2019.01933/full">antibiotic resistance</a> among bacteria. </p>
<p>Originally scientists thought this phenomenon was restricted to microbes, but we now know it also happens in a <a href="https://www.sciencedirect.com/science/article/abs/pii/S136952661500059X?via%3Dihub">wide range of plants</a>, <a href="https://www.sciencedirect.com/science/article/pii/S0092867421001641?via%3Dihub">animals</a> and <a href="https://academic.oup.com/evlett/article/2/2/88/6697442?login=true">fungi</a>, where it can spread the genetic recipe for traits that have an evolutionary advantage. </p>
<h2>Horizontal gene transfer in grasses</h2>
<p>Grasses are one of the most important groups of plants and include crops such as rice, wheat and maize. They cover almost 40% of the Earth’s landmass and make up the <a href="https://www.cell.com/current-biology/pdf/S0960-9822(10)01021-3.pdf">majority of human calorie intake</a>. </p>
<p>Horizontal gene transfer between grass species has been found in <a href="https://nph.onlinelibrary.wiley.com/doi/full/10.1111/nph.17328">wild and cultivated species alike</a>. While we know these transfers happen from the marks they leave in species’ <a href="https://www.genome.gov/genetics-glossary/Genome">genomes</a> (the entire set of DNA instructions in a cell), we still do not know the mechanism behind it. Neither do we know how often it happens – something <a href="https://nph.onlinelibrary.wiley.com/doi/10.1111/nph.19272">our recent study</a>, published in New Phytologist, aimed to address.</p>
<figure class="align-center ">
<img alt="Man stands in shirt sleeves in wheat field" src="https://images.theconversation.com/files/552487/original/file-20231006-15-91w9my.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/552487/original/file-20231006-15-91w9my.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/552487/original/file-20231006-15-91w9my.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/552487/original/file-20231006-15-91w9my.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/552487/original/file-20231006-15-91w9my.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/552487/original/file-20231006-15-91w9my.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/552487/original/file-20231006-15-91w9my.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Grasses make up a large part of humanity’s diet.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/young-farmer-standing-green-wheat-field-2311732409">Zoran Zeremski/Shutterstock</a></span>
</figcaption>
</figure>
<p>Understanding the pace of horizontal gene transfer would allow us to assess its impact upon the planet and plant evolution and how quickly it can help plants to adapt to changes. For example, is it common enough that plants could already be using it in response to climate change? </p>
<p>We sequenced several genomes for the tropical grass <em><a href="https://eol.org/pages/2896180">Alloteropsis semialata</a></em> to estimate the frequency of gene transfers into this species. Our study retraced the evolutionary history of each gene in the genome, identified genes that were of foreign origin, and worked out when and where they were transferred.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/552494/original/file-20231006-29-6ls4ci.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Grass with brown and yellow flowers." src="https://images.theconversation.com/files/552494/original/file-20231006-29-6ls4ci.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/552494/original/file-20231006-29-6ls4ci.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/552494/original/file-20231006-29-6ls4ci.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/552494/original/file-20231006-29-6ls4ci.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/552494/original/file-20231006-29-6ls4ci.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/552494/original/file-20231006-29-6ls4ci.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/552494/original/file-20231006-29-6ls4ci.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Alloteropsis semialata is also known as black seed grass.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Alloteropsis_semialata_flowers.jpeg">Marjorie Lundgren</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Our findings showed that genes were continually acquired throughout the evolutionary history of this species, with a foreign gene incorporated approximately every 35,000 years. </p>
<p>However, this is a dramatic underestimate of the real rate of transfers into the species because it doesn’t show gene transfers that may have been lost afterwards. Most transferred genes are unlikely to give the recipient any benefit – and can even have negative consequences for the plant if they disrupt essential parts of the recipient’s genetic code. Genes that don’t offer the recipient an advantage are often lost. It’s much harder for scientists to detect these kinds of transient genes. </p>
<p>The genes that are retained are generally those that offer the recipient an evolutionary advantage. For example, many of the horizontally transferred genes detected in grasses offer <a href="https://nph.onlinelibrary.wiley.com/doi/10.1111/nph.17328">disease resistance, stress tolerance and increased energy production</a>. These genes may have been optimised in the genomes of the donor species for millions of years. Horizontal gene transfer allows the recipient to skip this long refinement process. </p>
<h2>GM technology</h2>
<p>Ultimately horizontal gene transfer and GM crops have the same outcome: a gene of foreign origin is inserted into a recipient’s genome.</p>
<p>Our study gave an insight into how often horizontal transfers are happening. But we still don’t know how genes are moving between distantly related species. There are many theories but we think a mechanism called <a href="https://nph.onlinelibrary.wiley.com/doi/10.1002/ppp3.10347">reproductive contamination</a> is most likely. It mirrors some of the methods used to make GM crops. </p>
<p>There are several different methods by which you can make a GM plant – some that require intense human intervention and some that don’t. Simple techniques such as repeated pollination or <a href="https://pubmed.ncbi.nlm.nih.gov/30543062/#:%7E:text=There%20are%20three%20major%20steps,%3B%20Pollen%20tube%20pathway%3B%20Transformation.">pollen tube pathway-mediated transfer</a> require minimal human intervention. In these methods, small fragments of DNA from a third individual travel down the same pollen tube established by the father to contaminate the embryo in the seed. In theory this could occur naturally.</p>
<p>In the future we plan to test this idea and see if we can recreate some of the natural transfers we have documented. If successful, it may be time to reconsider how we view GM crops. Perhaps they are closer to natural processes than we think.</p><img src="https://counter.theconversation.com/content/215103/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Luke Dunning receives funding from The Natural Environment Research Council.</span></em></p><p class="fine-print"><em><span>Lara Pereira and Pauline Raimondeau do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Recent study investigated how fast genes are being transferred between distantly related species.Luke Dunning, Natural Environment Research Council Independent Research Fellow, University of SheffieldLara Pereira, Postdoctoral Research Associate in Genetics, University of SheffieldPauline Raimondeau, Postdoctoral Associate in Ecology & Evolutionary Biology, Yale UniversityLicensed as Creative Commons – attribution, no derivatives.