tag:theconversation.com,2011:/us/topics/insect-decline-45379/articlesInsect decline – The Conversation2023-09-21T15:09:18Ztag:theconversation.com,2011:article/2131222023-09-21T15:09:18Z2023-09-21T15:09:18ZHow air pollution is making life tougher for bugs<figure><img src="https://images.theconversation.com/files/548018/original/file-20230913-25-fwkjh6.jpg?ixlib=rb-1.1.0&rect=33%2C11%2C1273%2C1036&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Air pollution is the latest threat facing our insects.</span> <span class="attribution"><span class="source">Robbie Girling/Inka Lusebrink</span>, <a class="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/">CC BY-NC-SA</a></span></figcaption></figure><p>Whether you love them or loathe them, we all depend on bugs. Insects help to pollinate <a href="https://www.weforum.org/agenda/2019/12/protect-pollinators-food-security-biodiversity-agriculture/">three-quarters</a> of the world’s crop varieties, making them a treasured resource. </p>
<p>But we’re making the lives of insects tough – and not just by swatting them away with a newspaper. Insect populations worldwide are in <a href="https://www.cell.com/current-biology/pdf/S0960-9822(19)30796-1.pdf">sharp decline</a> as they battle against climate change, habitat loss and pesticides. </p>
<p>Now, we can add air pollution to the list of threats. <a href="https://www.sciencedirect.com/science/article/pii/S0269749122000616">Our research</a> from 2022 revealed that when exposed to two common air pollutants at concentrations within <a href="https://environment.ec.europa.eu/topics/air/air-quality/eu-air-quality-standards_en">EU air quality limits</a>, the visits of pollinating insects to flowers plummeted by as much as 90%. </p>
<p>Over a span of two years, we artificially elevated the levels of either ozone or diesel exhaust fumes around plots of flowering black mustard plants, all within fields of non-flowering wheat. We carefully monitored and controlled the release of pollutants using rings constructed around each plot. </p>
<p>This method allowed us to monitor the number of pollinating insects visiting the flowers in polluted plots and draw comparisons with plots devoid of pollutants.</p>
<p>We were surprised by what we found. In the rings where we released ozone or diesel exhaust fumes, the number of pollinating insects decreased by 70% and overall pollination success rates decreased by up to 31%. </p>
<p>It wasn’t just bees and butterflies that were affected. Ground-dwelling insects suffered too, with exposure to these pollutants <a href="https://www.frontiersin.org/articles/10.3389/fevo.2022.833088/full">causing their numbers to decrease</a> by as much as 36%.</p>
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<a href="https://images.theconversation.com/files/547556/original/file-20230911-15463-a7zcdo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A fenced off ring in the middle of a field." src="https://images.theconversation.com/files/547556/original/file-20230911-15463-a7zcdo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/547556/original/file-20230911-15463-a7zcdo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=173&fit=crop&dpr=1 600w, https://images.theconversation.com/files/547556/original/file-20230911-15463-a7zcdo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=173&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/547556/original/file-20230911-15463-a7zcdo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=173&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/547556/original/file-20230911-15463-a7zcdo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=217&fit=crop&dpr=1 754w, https://images.theconversation.com/files/547556/original/file-20230911-15463-a7zcdo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=217&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/547556/original/file-20230911-15463-a7zcdo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=217&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">Eight rings were used to elevate pollution levels around flowering black mustard plants.</span>
<span class="attribution"><span class="source">Neil Mullinger</span>, <a class="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/">CC BY-NC-SA</a></span>
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<h2>Why air pollution makes life so hard</h2>
<p>Many insects rely on their sense of smell to locate flowers. When they feed on nectar, they quickly connect the flower’s scent with its sugary reward. Consequently, when they come across the same scent later on, they track its trail in pursuit of another tasty treat. </p>
<p>Thus, flowers serve a dual purpose. They are not just pretty to look at but also function as beacons that release a specific blend of fragrant chemicals designed to attract pollinators. </p>
<p>But these signals are under threat. Air pollutants like ozone are highly reactive and can degrade the signals by destroying the chemicals that make up a flower’s scent.</p>
<p>In our more <a href="https://www.sciencedirect.com/science/article/pii/S0269749123013386?via%3Dihub">recent research</a>, we simulated a floral scent in a 20-metre long wind tunnel and then mapped out how the levels of each of the chemicals that made up the scent changed in response to increasing ozone pollution. We found that ozone quickly ate away at the edges of the plume, reducing both its width and length. </p>
<p>Essentially, the chemical signal could travel only a shorter distance, which limited the number of insects it could reach.</p>
<p>Adding ozone also changes the smell of each of the chemicals that make up a flower’s scent. By observing these changes in a wind tunnel, we could measure the speed at which these chemical changes occur. </p>
<p>Some chemicals degraded within seconds, whereas others were not affected at all. How far away you are from the scent’s source appears to change how the scent smells.</p>
<h2>Pavlov’s Bees</h2>
<p>To understand how changes to the floral scent might affect pollinators, we taught honeybees to recognise the same floral scent that we released into the wind tunnel. Much like <a href="https://www.simplypsychology.org/pavlov.html">Pavlov’s dogs</a> drooling at the sound of a dinner bell, <a href="https://www.youtube.com/watch?v=Pg2DSfuZDAk">bees stick out their proboscis</a> (tube-like tongue) when they sniff an odour they have learned to associate with a sugary reward. This allowed us to see how many bees could still recognise the floral scent once it had been exposed to ozone pollution. </p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/Pg2DSfuZDAk?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Like Pavlov’s dogs, bees can be trained to respond to a dinner bell – or in their case, the scent of a flower.</span></figcaption>
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<p>We first tested the <a href="https://www.britannica.com/animal/honeybee">honeybees</a> with scent blends replicating those observed at the plume centre when ozone levels were elevated. At a distance of six metres from the flower, 52% of bees recognised the scent. This fell to only 38% at a distance of 12 metres. </p>
<p>We then tested the response of honeybees to the more degraded plume edges. Only 32% of the bees responded at six metres, falling to just 10% at 12 metres. </p>
<p>These results help to explain the significant decline in the number and diversity of insect visits and pollination rates observed in our field trials. Put simply, ozone pollution limits the reach of chemical signals and changes their meaning, leaving insects confused.</p>
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<a href="https://images.theconversation.com/files/547727/original/file-20230912-21-4ef5j9.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Two diagrams showing how ozone disrupts a flower's scent." src="https://images.theconversation.com/files/547727/original/file-20230912-21-4ef5j9.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/547727/original/file-20230912-21-4ef5j9.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=358&fit=crop&dpr=1 600w, https://images.theconversation.com/files/547727/original/file-20230912-21-4ef5j9.PNG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=358&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/547727/original/file-20230912-21-4ef5j9.PNG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=358&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/547727/original/file-20230912-21-4ef5j9.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=450&fit=crop&dpr=1 754w, https://images.theconversation.com/files/547727/original/file-20230912-21-4ef5j9.PNG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=450&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/547727/original/file-20230912-21-4ef5j9.PNG?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">Ozone makes it difficult for insects to sniff out flowers.</span>
<span class="attribution"><span class="source">Ben Langford</span>, <a class="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/">CC BY-NC-SA</a></span>
</figcaption>
</figure>
<p>But this is unlikely to be the full story. Although we replicated the effects of ozone pollution on floral scents, we never exposed the bees directly to ozone. <a href="https://www.sciencedirect.com/science/article/pii/S0048969722014358">Separate research</a> carried out in France suggests that direct exposure to ozone might also impair the ability of bees to detect floral scents. </p>
<p>The full extent to which air pollution is impacting the insects we all depend on is only just beginning to be revealed. So, the next time you lift your newspaper to swat a bug, take a second and ask yourself – don’t they have it tough enough already?</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 class="fine-print"><em><span>Ben Langford receives funding from the Natural Environmental Research Council</span></em></p><p class="fine-print"><em><span>James Ryalls has received funding from The Leverhulme Trust and The Royal Society to conduct research on this topic.</span></em></p><p class="fine-print"><em><span>Robbie Girling has received funding to conduct research on this topic from the Natural Environment Research Council, the Leverhulme Trust and the Gerald Kerkut Charitable Trust. </span></em></p>We’re making life tough for insects – and not just by swatting them away with a newspaper.Ben Langford, Senior Atmospheric Scientist, UK Centre for Ecology & HydrologyJames Ryalls, Research Fellow in the School of Agriculture, Policy and Development, University of ReadingRobbie Girling, Director of the Centre for Sustainable Agricultural Systems, University of Southern QueenslandLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2063902023-05-25T01:01:52Z2023-05-25T01:01:52ZCould wildflowers and bug hotels help avert an insect apocalypse? We just don’t know – yet<figure><img src="https://images.theconversation.com/files/528125/original/file-20230524-29-9g5xse.jpg?ixlib=rb-1.1.0&rect=7%2C54%2C5160%2C3383&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Getty Images</span></span></figcaption></figure><p>Insects are in rapid decline. One study found the global total is falling by <a href="https://www.sciencedirect.com/science/article/abs/pii/S0006320718313636">2.5% a year</a>, with insect species going extinct eight times faster than mammals, birds and reptiles. </p>
<p>While scientists don’t yet know when insect populations could drop to the point of no return, we can’t keep losing species without, ultimately, a catastrophic outcome. </p>
<p>Many people are concerned about insect biodiversity and trying do something about it. One way is to give some habitat back to insects. <a href="https://www.stuff.co.nz/life-style/homed/garden/119011599/how-to-grow-a-wildflower-meadow">Wildflower meadows</a>, for example, are being sown in parks and other urban green spaces. </p>
<p>Typically, these are mixtures of mostly non-native species chosen to provide nectar, pollen, and other resources for insects, as well as visual floral appeal. They are often deployed for other reasons, like reducing the need for mowing and its associated costs and carbon footprint. </p>
<p>But before we plant wildflower fields or build “bug hotels”, we need to better understand how these measures help – and when they don’t. The lack of robust research means there is still a lot we don’t know. Our team of researchers at the University of Canterbury is trying to fill some of this knowledge gap.</p>
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<h2>What we don’t know</h2>
<p>The long-term potential of wildflowers is unclear. They seem to attract insects, but there are many unanswered questions. </p>
<p>Do these insects come from elsewhere or is there a genuine bolstering of populations? Which insects benefit most? What is the balance between pests and beneficial species? Can exotic plants support an increase in native insects? Do the effects extend beyond planted areas, and if so, how far?</p>
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Read more:
<a href="https://theconversation.com/insects-worldwide-study-reveals-widespread-decline-since-1925-137089">Insects: worldwide study reveals widespread decline since 1925</a>
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<p>Bug hotels, which generally consist of artificial homes for insects, raise similar questions. As their design, materials, and construction are more variable, it’s even more difficult to assess their efficacy. </p>
<p>This is something we need examine further as some designs may be more effective than others. This will depend on the mix of insects in the vicinity. What works well in one place may be counter-productive in another.</p>
<h2>Long-term commitment</h2>
<p>Enthusiasm for sowing wildflowers and building bug refuges rarely extends to ongoing upkeep and long-term monitoring. Many studies are short-term, local scale, and rather ad hoc, making it difficult to compare and draw broader conclusions. </p>
<p>The results are often unpublished or difficult to find, hidden in reports about other things. This means, if we are to use these insect ecosystem revival approaches effectively, we need to draw this evidence together and implement more long-term studies across a wide variety of contexts.</p>
<p>Fortunately, studies like this are relatively easy to do. They just require a commitment to keeping them going. We also need to be sharing the results in ways that allow meaningful comparisons. </p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/insects-are-vanishing-worldwide-now-its-making-it-harder-to-grow-food-199826">Insects are vanishing worldwide – now it's making it harder to grow food</a>
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<p>The research methods used by scientists to study insect populations don’t require expensive equipment and can easily be replicated by volunteers, community groups and school students of all ages. For example, <a href="https://www.nhm.ac.uk/discover/how-to-make-pitfall-trap-to-catch-insects.html">pitfall traps</a>, which measure insect activity on the ground, can be yoghurt pots sunk into the soil. </p>
<p>The educational possibilities are many, from science fair projects to basic numeracy skills. Similar to birdwatching, volunteers could do five-minute bug counts to see what insects visit flowers and “hotels”. </p>
<p>Other entomological methods such as “beating” (shaking a low-hanging branch over a white sheet to see what falls out) are just as easy. The important point is to choose methods and a sampling frequency that are sustainable, and stick to it.</p>
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<h2>Understanding bug populations</h2>
<p>Baseline studies before establishing a meadow or bug hotel would make research like this even more effective, but this is rarely done. This is why we have been doing baseline studies of areas where wildflower meadows are planned at the University of Canterbury. We want to understand the environment, and insect populations, before the introduction of the wildflowers.</p>
<p>Although all the available evidence suggests these meadows will significantly increase the number and diversity of insects in the area, it’s surprising how many insects we’ve found in our baseline studies, including lots of tiny parasitic wasps, which tell us the insects they live off must also be around, even though we have not seen so many of them. </p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/what-happens-to-the-natural-world-if-all-the-insects-disappear-111886">What happens to the natural world if all the insects disappear?</a>
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<p>These baseline studies will allow us to see how the composition of the insect community changes after meadows are sown. We may even find some kinds of insects decrease in numbers while others flourish. These details are important for assessing the overall impacts of the meadow.</p>
<p>In the process, we may also counter the trend towards disconnection from nature, particularly among young people. Wildflower meadows, bug hotels and other interventions could be a wonderful way to “rewild” our urban spaces, and bring some nature back into people’s lives. </p>
<p>If we want to know the best way to use such measures, however, we need to monitor their impacts. This can be an interesting, fun way to engage with and learn about nature, and to add value to community gardens and replanting projects.</p>
<p>It can also provide important scientific data to help us more effectively provide the space insects need to thrive alongside us.</p><img src="https://counter.theconversation.com/content/206390/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Rob Cruickshank 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>There’s a lot of enthusiasm for wildflower fields and bug hotels. But before introducing these insect-saving measures, we need to better understand when they help – and when they don’t.Rob Cruickshank, Lecturer – Teaching & Administration, University of CanterburyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1390152020-07-09T20:46:18Z2020-07-09T20:46:18ZSmaller farmer’s fields can reduce biodiversity loss and increase wild plants, birds, beetles and bats<figure><img src="https://images.theconversation.com/files/346439/original/file-20200708-3999-d0dxao.jpg?ixlib=rb-1.1.0&rect=29%2C25%2C2238%2C1318&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Smaller farmers fields can be beneficial to wild species. </span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><p>Around the world, biodiversity is dropping precipitously. In North America, about <a href="https://www.doi.org/10.1126/science.aaw1313">three billion birds</a> have been lost over recent decades and <a href="https://www.nature.com/articles/srep25625">amphibian populations</a> are declining at a rate of about four per cent per year. Globally, <a href="https://www.doi.org/10.1126/science.aax9931">insects are vanishing</a> at a rate of about nine per cent per decade. </p>
<p>This is distressing for nature lovers. It is also worrying on a practical level: in agricultural landscapes, <a href="https://doi.org/10.1016/j.agee.2012.06.020">wild species</a> perform many important activities such as pollination and control of insect pests.</p>
<p>A highly effective way to reduce biodiversity losses in agricultural regions is to increase the amount of natural and semi-natural habitats such as forests, hedgerows, prairie strips and other non-crop areas. This has led to various government <a href="https://doi.org/10.1016/j.jnc.2015.12.006">incentives for farmers to leave some areas out of production</a>. But <a href="https://doi.org/10.1007/s00267-013-0106-9">there are limits</a> to how much land farmers can leave for biodiversity, while foregoing opportunities for crop production.</p>
<h2>The benefit of small crop fields</h2>
<p>Small fields can help. <a href="https://doi.org/10.1073/pnas.1906419116">Farmers can maintain or increase biodiversity</a> in agricultural landscapes by <a href="https://doi.org/10.1016/j.agee.2014.11.018">planting their crops in smaller fields</a>. </p>
<p>For example, instead of planting two large fields, they could plant eight small fields, keeping the same total amount of land in production. Note that this is not about the size of a farm, but about the average size of crop fields. </p>
<p>A very large farm could, in theory, be composed of a very large number of small fields, where a “field” is an area in a particular crop type, such as a corn field or a hay field. Adjacent areas in the same crop type are separate fields if they are divided by even a narrow bit of non-field such as a hedgerow, a fence line, a track or a ditch. </p>
<p>My colleagues and I have found remarkably consistent increases in biodiversity with decreasing average field size, across eight very different agricultural regions in five countries — and for a wide array of wildlife types. </p>
<p>The number of <a href="https://doi.org/10.1111/1365-2664.13585">species of plants</a>, <a href="https://doi.org/10.1098/rspb.2017.2242">pollinators including bees, butterflies and syrphid flies</a>, and pest-eating wildlife such as spiders, carabid beetles, birds, <a href="https://doi.org/10.1016/j.agee.2016.12.038">frogs</a> and <a href="https://doi.org/10.1016/j.agee.2017.11.001">bats</a>, all increase with decreasing average field size. For example, biodiversity is about 50 per cent higher when the average field size drops to two hectares from eight hectares.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/346730/original/file-20200709-87067-1ednsnz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/346730/original/file-20200709-87067-1ednsnz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/346730/original/file-20200709-87067-1ednsnz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/346730/original/file-20200709-87067-1ednsnz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/346730/original/file-20200709-87067-1ednsnz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/346730/original/file-20200709-87067-1ednsnz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/346730/original/file-20200709-87067-1ednsnz.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">Pest-eating wildlife, such as this carabid beetle, can benefit crops.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>In fact, the benefit to biodiversity of reducing crop field sizes appears to be greater than two other commonly suggested methods for increasing biodiversity in agricultural landscapes — <a href="https://doi.org/10.1016/j.agee.2019.106698">reducing pesticide use</a> and increasing crop diversity, the number of different crop types grown in a landscape.</p>
<h2>The best of both worlds</h2>
<p>One question is whether the increased biodiversity is due to the additional non-cropped strips of semi-natural land, such as hedgerows, between fields. In other words, is there actually less cropland — and more semi-natural land — in an agricultural landscape with eight small fields than in a landscape with two large ones? </p>
<p>Our research shows that in fact biodiversity is higher in a landscape with smaller crop fields, even for the same total amount of natural and semi-natural habitat, including all the little pieces such as hedgerows.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/346440/original/file-20200708-3983-y4hggc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/346440/original/file-20200708-3983-y4hggc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=335&fit=crop&dpr=1 600w, https://images.theconversation.com/files/346440/original/file-20200708-3983-y4hggc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=335&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/346440/original/file-20200708-3983-y4hggc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=335&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/346440/original/file-20200708-3983-y4hggc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=421&fit=crop&dpr=1 754w, https://images.theconversation.com/files/346440/original/file-20200708-3983-y4hggc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=421&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/346440/original/file-20200708-3983-y4hggc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=421&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Small strips of natural and semi-natural habitat, like this hedgerow, can provide wildlife with an area for food, breeding or an escape from farming operations.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>We don’t know yet why biodiversity is higher in landscapes with smaller crop fields. One possibility is that when crop fields are smaller, the natural habitats are closer together.</p>
<p>This would increase the ability of wildlife to <a href="https://doi.org/10.1016/j.agee.2018.08.025">easily access</a> natural habitats from crop fields. Crop fields may provide temporary food sources for wildlife, such as when a crop is in flower or when there is a pest outbreak. Natural areas are also needed for breeding and overwintering sites and for escape from farming operations such as plowing. </p>
<p>When wildlife can easily move back and forth between crops and natural spaces, perhaps they have access to the best of both worlds. </p>
<h2>The farmer’s dilemma</h2>
<p>Altogether, <a href="https://doi.org/10.1146/annurev-ecolsys-110316-022612">our research suggests</a> a “<a href="https://doi.org/10.1111/geb.13059">many small</a>” approach to support biodiversity in agricultural landscapes. </p>
<p>But can farmers readily reduce the sizes of fields? In many <a href="https://doi.org/10.1002/geo2.4">parts of the world, just the opposite</a> has been happening over the past 50 years. </p>
<p>Fields are being consolidated by removing the tracks, fences, stone walls and hedgerows that once separated them. Farmers do this to increase the efficiency of their operations. But in doing so, they reduce the populations of wildlife that help support agriculture. </p>
<p>The net cost or benefit to farmers of reducing field sizes while maintaining the same area in production has not yet been studied. But the benefits to biodiversity are now clear.</p><img src="https://counter.theconversation.com/content/139015/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Lenore Fahrig receives funding from the Natural Sciences and Engineering Research Council of Canada (NSERC).</span></em></p>The steep decline in biodiversity is worrying, especially as wild species are important for pollination and pest control.Lenore Fahrig, Chancellor's Professor of Biology, Carleton UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1391932020-06-18T15:26:43Z2020-06-18T15:26:43ZCOVID-19 shutdowns will give wildlife only short-term relief from climate change and other threats<figure><img src="https://images.theconversation.com/files/342507/original/file-20200617-94060-tvrc3t.jpg?ixlib=rb-1.1.0&rect=108%2C79%2C3580%2C2157&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Wildflowers proliferating in overgrown roadsides during the coronavirus pandemic are providing habitat for pollinators. </span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><p>There had to be a silver lining to the nearly universal lockdown of the COVID-19 pandemic. One of the small benefits has been a temporarily lighter human footprint in many ecosystems. </p>
<p><a href="https://theconversation.com/coronavirus-closures-could-lead-to-a-radical-revolution-in-conservation-137050">Wildlife sightings are increasing</a>, <a href="https://www.sciencedaily.com/releases/2020/05/200511124444.htm">air quality is improving</a> and <a href="https://www.carbonbrief.org/daily-global-co2-emissions-cut-to-2006-levels-during-height-of-coronavirus-crisis">carbon emissions are dropping</a>. While these glimmers of positivity cannot come close to eclipsing the tragic human cost of the coronavirus, many are now asking what the pandemic will mean for wildlife around the globe. </p>
<p>Global carbon dioxide emissions for 2020 are <a href="https://www.carbonbrief.org/iea-coronavirus-impact-on-co2-emissions-six-times-larger-than-financial-crisis">expected to fall by up to eight per cent due to shutdowns</a>, although the <a href="https://www.smithsonianmag.com/smart-news/carbon-emissions-fall-during-pandemic-could-bounce-back-fast-180974930/">resumption of global activity could increase emissions and offset some of these gains</a>. While this is a significant reduction in our expected emissions, it’s far from enough to turn the tide on climate change’s impacts on biodiversity.</p>
<p>Climate change can’t be stopped by COVID-19. This past <a href="https://climate.copernicus.eu/surface-air-temperature-april-2020">April</a> and <a href="https://www.noaa.gov/news/may-2020-tied-for-hottest-on-record-for-globe">May were both tied for the warmest on record</a>, and if this trend continues then <a href="https://www.washingtonpost.com/weather/2020/05/05/global-warming-pushes-april-temperatures-into-record-territory-2020-heads-disquieting-milestone/">June will be the 426th month in a row where global average temperatures are above the 20th-century average</a>. This serves as a strong reminder that even if we stop all carbon emissions today, we will still be fighting to reduce emissions and sequester carbon for a long time. The stakes are dangerously high.</p>
<h2>Lessons from the bees</h2>
<p>We’ve known for a while that bumblebees and many other species have been <a href="https://wwf.panda.org/knowledge_hub/all_publications/living_planet_index2/">declining over recent decades</a>. Finding the driver of these declines is especially important for a group of pollinators that performs <a href="https://doi.org/10.1016/j.tree.2010.01.007">irreplaceable ecosystem and agriculture services</a>.</p>
<p>Recently, we showed that there is <a href="https://doi.org/10.1126/science.aax8591">strong evidence that climate change has played a role in the declines of bumblebees across North America and Europe</a>. In this new work, we found a mechanism that links climate change to these pollinator declines: climate chaos. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/340202/original/file-20200607-176550-12s83ng.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/340202/original/file-20200607-176550-12s83ng.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/340202/original/file-20200607-176550-12s83ng.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/340202/original/file-20200607-176550-12s83ng.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/340202/original/file-20200607-176550-12s83ng.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/340202/original/file-20200607-176550-12s83ng.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/340202/original/file-20200607-176550-12s83ng.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"><em>Bombus ternarius</em>, the tricoloured bumblebee, seen on Manitoulin Island, Ont.</span>
<span class="attribution"><span class="source">(Peter Soroye)</span></span>
</figcaption>
</figure>
<p>The most common way to describe climate change is as the progressive rise in temperature, observed over decades, following the growth in atmospheric carbon concentrations, mostly due to human activities. Although gradual temperature changes can pose deadly threats, the frequency and intensity of extreme weather events seems to be rising sharply as the greenhouse effect grows. Heat waves, for example, are both longer and hotter. </p>
<p>As Hamlet noted, “ay, there’s the rub.” </p>
<p>Wildlife can tolerate some degree of warming, either by finding ways to move away from risky weather or evolutionary adaptation. But it’s much <a href="https://doi.org/10.1016/j.cois.2020.01.007">more difficult for species to tolerate increasingly chaotic extremes in weather</a> such as <a href="https://www.c2es.org/content/extreme-weather-and-climate-change/">prolonged drought and heat waves, or tropical storms</a>. </p>
<h2>100 years of bumblebee data</h2>
<p>For bumblebee species, we could predict local extinction and colonization of new areas by estimating whether recent climate change had subjected species to temperatures beyond any they are known to have tolerated in the past. </p>
<p>Through a series of tests with a dataset including over 100 years of bumblebee observations, we found that species have disappeared in places where temperature spiked above what they could tolerate. Species across North America and Europe are consistently being pushed to the edges of these limits during the year, much more often than they ever were for most of the 20th century. Increasing intensity of land use — including increased pesticide use — also harms bees, but these effects are distinct from the dangerous signal of climate chaos. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/3zyr5G6MI8M?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Average annual temperatures (map) and monthly extremes (shown in the right-hand inset with year in red compared to a baseline period in grey) have been increasing across North America and Europe from 1975-2015, resulting in declines for the bumblebees (estimated average annual decline for a species shown in left-hand inset)</span></figcaption>
</figure>
<p>While our recent study focused on bees, increasing extremes from climate change should, in principle, affect other species in the same way. If this is the case, then the increasing temperature or precipitation extremes above (or below) the limits of what species can tolerate could <a href="https://doi.org/10.1038/s41586-020-2189-9">rapidly and abruptly begin reshaping ecosystems around the globe by as early as 2030</a>. </p>
<h2>Necessary responses</h2>
<p>Although we’ll feel the effect of climate change for decades, it’s necessary to address its causes now while we still have reasonable prospects of mitigating its worst impacts. Strategies like maintaining <a href="https://doi.org/10.1111/gcb.12439">sheltered micro-habitats to provide shade or cover</a>, and keeping a diversity of habitats in a landscape can help reduce exposure of species to extreme weather. </p>
<p>Perhaps, humanity’s lighter touch during the pandemic of 2020 will mean more species can traverse landscapes or make it through another hot year in landscapes that are a little less disturbed. For instance, the <a href="https://www.bbc.com/future/article/20200506-why-lockdown-is-helping-bees">profusion of wildflowers in unmaintained roadside verges</a> could create a large amount of nesting and foraging habitat for pollinators if left for the whole year. </p>
<p>The growing number of <a href="https://www.cbc.ca/news/canada/toronto/covid-19-food-security-gardening-1.5519635">gardens that are appearing as people spend more time at home</a> could provide a similar benefit. As with reductions in emissions, continuing these practices long after lockdowns end will be the deciding factor in whether they make a difference for pollinators and other wildlife.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/growing-your-own-food-during-the-coronavirus-pandemic-plan-for-pests-136793">Growing your own food during the coronavirus pandemic? Plan for pests!</a>
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</em>
</p>
<hr>
<p>In some places, <a href="https://doi.org/10.1016/j.biocon.2020.108571">species and ecosystems are bouncing back</a>, although <a href="https://newsroom.wcs.org/News-Releases/articleType/ArticleView/articleId/14039/COVID-19-FUELING-AN-UPTICK-IN-POACHING-Three-Critically-Endangered-Giant-Ibis-Cambodias-National-Bird-Killed-in-Protected-Area.aspx">this is not true everywhere</a>: as economies suffer, poachers are killing protected wildlife. </p>
<p>The glimmers of hope will never make the incalculable human toll of a global pandemic worthwhile, nor its economic costs. Yet, hope remains a vital tool to motivate action to address climate change. </p>
<p>Climate change isn’t locked down and it isn’t practising social distancing. It is accelerating the erosion of the planet’s life support systems and the decline of species that humanity would be hard pressed to do without. Concerted global action can make dangerous situations better, whether it’s a pandemic or the climate crisis.</p><img src="https://counter.theconversation.com/content/139193/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Peter Soroye receives funding from the Natural Sciences and Engineering Research Council of Canada.</span></em></p><p class="fine-print"><em><span>Jeremy Kerr receives funding from the Natural Sciences and Engineering Research Council of Canada (NSERC), the Canadian Foundation for Innovation (CFI), the Royal Society, and MITACS. </span></em></p><p class="fine-print"><em><span>Tim Newbold receives funding from the Royal Society and from the UK Natural Environment Research Council.</span></em></p>Temporary reductions in carbon dioxide during the pandemic won’t turn the tide on climate change or biodiversity loss, but summon the need for action.Peter Soroye, PhD Student in Conservation Biology, L’Université d’Ottawa/University of OttawaJeremy Kerr, Research Chair in Macroecology and Conservation, Professor of Biology, Chair of Department of Biology, L’Université d’Ottawa/University of OttawaTim Newbold, Senior research fellow, Centre for Biodiversity and Environment, UCLLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1370892020-04-23T18:14:03Z2020-04-23T18:14:03ZInsects: worldwide study reveals widespread decline since 1925<p>When did you last see a glow worm? Most likely, quite some time ago. Depending on how young you are, you may have never seen one at all. Those light-emitting insects, Wordsworth’s “earthborn stars”, <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/icad.12407">have been declining in the UK for decades</a>. That means that scientists now see them in fewer places, and even in those pockets where conditions are right for them, there are fewer of them to be found. </p>
<p>But it isn’t just glow worms that are struggling. You’ll have heard reports that <a href="https://www.annualreviews.org/doi/abs/10.1146/annurev-ento-011019-025151">insects are declining</a> in many parts of the world, with fewer of them around and some species disappearing altogether. Many people have noted that the number of “splats” you’re likely to see on a car windscreen in summer is now much lower compared with 20 years ago, and this has even been confirmed by <a href="https://onlinelibrary.wiley.com/doi/full/10.1002/ece3.5236">a scientific study</a>. As scientists who study insects, we’re right to be worried, but how sure can we be sure of the general picture if we only have information about particular species in particular places?</p>
<p>Fortunately, <a href="https://science.sciencemag.org/content/368/6489/417">a new study</a> has offered the clearest indication yet of how insects all over the world are faring. The researchers studied data on the numbers and total weight of insects and arachnids (spiders and mites) sampled in 166 long-term surveys. Each of these lasted more than ten years and recorded insects at 1,676 sites in 41 countries on five continents. The earliest record was from 1925, and the most recent from 2018, although most records were dated from 1986 or later.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/330070/original/file-20200423-47810-16tvdw3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/330070/original/file-20200423-47810-16tvdw3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=402&fit=crop&dpr=1 600w, https://images.theconversation.com/files/330070/original/file-20200423-47810-16tvdw3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=402&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/330070/original/file-20200423-47810-16tvdw3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=402&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/330070/original/file-20200423-47810-16tvdw3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=505&fit=crop&dpr=1 754w, https://images.theconversation.com/files/330070/original/file-20200423-47810-16tvdw3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=505&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/330070/original/file-20200423-47810-16tvdw3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=505&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"><em>Lampyris noctiluca</em>, or the common glow worm of Europe.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/lampyris-noctiluca-1234765510">Igor Krasilov/Shutterstock</a></span>
</figcaption>
</figure>
<p>They estimate that land-based insects, which make up the majority of species, have been declining at nearly 1% per year, or almost 9% per decade. But during the same period, the small proportion of insects which live in freshwater experienced a 1% annual increase, or just over 11% per decade.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/meet-the-insects-that-are-defying-the-plunge-in-biodiversity-new-findings-131846">Meet the insects that are defying the plunge in biodiversity – new findings</a>
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</em>
</p>
<hr>
<h2>A complicated picture</h2>
<p>Does this give us cause to be relatively cheerful (or at least, less miserable)? Hardly. While these estimates of how rapidly insect populations are declining are much lower than <a href="https://onlinelibrary.wiley.com/doi/10.1111/icad.12408">some previous estimates</a>, it’s still serious. The general rate of decline may be an underestimate, too – most of the long-term data came from protected populations of insects in nature reserves.</p>
<p>Even if you’re not enamoured with creepy crawlies, their gradual disappearance from the places they were once numerous is an ongoing crisis for the natural world. Insects and small invertebrates occupy the bottom rungs of most terrestrial ecosystems. As ecologist E.O. Wilson once observed, if you take away the “<a href="https://conbio.onlinelibrary.wiley.com/doi/10.1111/j.1523-1739.1987.tb00055.x">little things that run the world</a>” then most of the creatures occupying niches further up the food chain will disappear too, and that includes humans. That’s why <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0185809">a 2017 study in Germany</a> rang so many alarm bells – it reported a 75% decline over 27 years in the local biomass of all kinds of flying insects.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/330073/original/file-20200423-47794-1y2pt1b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/330073/original/file-20200423-47794-1y2pt1b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/330073/original/file-20200423-47794-1y2pt1b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/330073/original/file-20200423-47794-1y2pt1b.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/330073/original/file-20200423-47794-1y2pt1b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/330073/original/file-20200423-47794-1y2pt1b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/330073/original/file-20200423-47794-1y2pt1b.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">
<figcaption>
<span class="caption">When was the last time you saw a bug splat on a car windscreen?</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/focus-on-splattered-yellow-bug-guts-1394031878">Vesperstock/Shutterstock</a></span>
</figcaption>
</figure>
<p>But what does a “general decline” mean? It doesn’t mean that every kind of insect is affected in the same way. Several recent studies have shown that some species are able to prosper while their close relatives die out. <a href="https://theconversation.com/insects-species-that-prefer-crops-prosper-while-majority-decline-114206">A study of wild pollinators</a> (bees and hoverflies) in the UK between 1980 and 2013 showed that around 10% of these insects increased in abundance while more than 30% declined. The insects that did well were crop specialist pollinators, those that didn’t were those specialists that preferred plants pushed out of farmed landscapes.</p>
<p>It’s a complicated picture, but the sheer number of records collected under different conditions from diverse sources in this new study gives grim confirmation that something is very wrong.</p>
<h2>What it means for conservation</h2>
<p>While the picture of widespread insect declines is becoming a little clearer, we still don’t know the cause. The new study found some evidence that the growth of cities and towns nearby was detrimental to insect abundance. Perhaps surprisingly, there was little evidence for insect populations being harmed by neighbouring intensive agriculture, but this might have been because those sites were already depleted of insects when the study began. </p>
<p>There was also no evidence for climate change affecting insect abundance. Terrestrial insects seemed to be worst affected in Europe and North America, with insects in Asia, South America and Oceania showing no great declines. This likely reflects the fact that there’s less information from these places, though. Interestingly, terrestrial insect populations in North America have recovered markedly since 1990, while those in Europe have shrunk still further. There is no obvious explanation for this.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/330074/original/file-20200423-47826-14kwyc6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/330074/original/file-20200423-47826-14kwyc6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/330074/original/file-20200423-47826-14kwyc6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/330074/original/file-20200423-47826-14kwyc6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/330074/original/file-20200423-47826-14kwyc6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/330074/original/file-20200423-47826-14kwyc6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/330074/original/file-20200423-47826-14kwyc6.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">Mayflies are aquatic insects, which are among the few winners in the new study.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/giant-mayfly-close-1548530867">Trishazdigilife/Shutterstock</a></span>
</figcaption>
</figure>
<p>The apparent healthiness of aquatic insects <a href="https://www.nature.com/articles/s41559-020-1111-z">confirms the results of a recent UK study</a>, which suggested that EU legislation to clean up rivers throughout Europe <a href="https://theconversation.com/meet-the-insects-that-are-defying-the-plunge-in-biodiversity-new-findings-131846">may be working</a>. Sounds encouraging, but fresh water only <a href="http://www.unesco.org/new/fileadmin/MULTIMEDIA/FIELD/Venice/pdf/special_events/bozza_scheda_DOW02_1.0.pdf">covers 2.4% of the Earth’s land surface</a>. The comparative success of aquatic insects doesn’t make up for everywhere else, and it might even conceal the collapse of some water dwellers, like <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/icad.12411">water beetles</a> and the superabundant mayfly swarms of the North American Great Lakes and Upper Mississippi which used to number in the tens of billions <a href="https://www.pnas.org/content/117/6/2987">but have declined by around 50%</a> in recent years.</p>
<p>The German federal government recently <a href="https://www.sciencemag.org/news/2019/09/100-million-german-insect-protection-plan-will-protect-habitats-restrict-weed-killers">approved €100 million for insect conservation</a>, with a quarter of it going towards research. Knowing where and why certain species are struggling is as important as trying to fix it. Insects are in trouble, but each bug faces its own battle. Support for our arthropod friends will need to be carefully targeted.</p><img src="https://counter.theconversation.com/content/137089/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Stuart Reynolds is a former President of the Royal Entomological Society.</span></em></p>The largest study of insect declines to date gives us the best indication of how species all over the world are faring.Stuart Reynolds, Emeritus Professor of Biology, University of BathLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1330512020-03-09T19:02:08Z2020-03-09T19:02:08ZMalnourished bugs: Higher CO2 levels make plants less nutritious, hurting insect populations<figure><img src="https://images.theconversation.com/files/319431/original/file-20200309-118881-1bbmkgn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">These grasshoppers, like many insects around the world, are declining. </span> <span class="attribution"><span class="source">Dave Rintoul</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p><em>The Research Brief is a short take on interesting academic work.</em></p>
<h2>The big idea</h2>
<p>Grasshopper populations, like those of many other insects, <a href="https://doi.org/10.1146/annurev-ento-011019-025151">are declining</a>. My colleagues and I identified a new possible culprit: The plants grasshoppers rely on for food are becoming less nutritious due to increased levels of carbon dioxide in the air.</p>
<p><a href="https://www.esrl.noaa.gov/gmd/ccgg/trends/">Ever-increasing levels of carbon dioxide</a> in the atmosphere tend to <a href="https://doi.org/10.1038/s43017-019-0001-x">promote plant growth by supplying them with extra carbon</a>. But all that added carbon is <a href="https://doi.org/10.7554/eLife.02245">squeezing out other nutrients</a> that plant feeders – like insects and people – need to thrive. These fast-growing plants end up less dense in nutrients like nitrogen, phosphorus and sodium – more like iceberg lettuce than kale.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/319430/original/file-20200309-118960-sq3cff.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/319430/original/file-20200309-118960-sq3cff.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/319430/original/file-20200309-118960-sq3cff.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/319430/original/file-20200309-118960-sq3cff.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/319430/original/file-20200309-118960-sq3cff.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=565&fit=crop&dpr=1 754w, https://images.theconversation.com/files/319430/original/file-20200309-118960-sq3cff.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=565&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/319430/original/file-20200309-118960-sq3cff.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=565&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The Konza Prairie, a protected grassland in Kansas, is a unique research area: decades of data and minimal human influence.</span>
<span class="attribution"><span class="source">Ellen Welti</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>On our study site in a Kansas prairie, my colleagues and I show that across more than 40 species of grasshoppers, <a href="https://www.pnas.org/content/early/2020/03/03/1920012117">total populations are falling at more than 2% a year</a>. This led to an overall reduction in grasshopper numbers over the past two decades of about one-third. These population declines parallel the <a href="http://doi.org/10.6073/pasta/2cf2858e0a8cf82c99f91cfcf191bc14">decline in grassland nutrients</a>. Grasshopper populations vary year to year for many reasons, but my colleagues and I believe that the dilution of plant nutrients caused by elevated CO2 is the most likely reason for the decline.</p>
<p>It adds up to what we call the “nutrient dilution hypothesis”: Increased CO2 is making plants less nutritious per bite and insects are paying the price.</p>
<h2>Why it matters</h2>
<p>Ecologists have thus far focused on pesticide use and the loss of native habitats as causes for insect declines.</p>
<p>These factors aren’t likely at the <a href="http://lter.konza.ksu.edu/konza-prairie-long-term-ecological-research-lter">large native prairie reserve</a> where I work. Yet the 2% per year decline in grasshoppers our study found is eerily similar to the 2% declines reported from long-term studies around the globe of <a href="https://doi.org/10.1371/journal.pone.0216270">moths and butterflies</a>, whose young – caterpillars – are also voracious plant feeders.</p>
<p>Other factors, like pesticide use and habitat destruction, are certainly <a href="https://doi.org/10.1111/icad.12367">hurting insect populations in many places</a>. But since CO2 is increasing globally, my colleagues and I suspect that nutrient dilution is likely bad news for plant-eating insects across a huge variety of habitats, in both pristine and degraded ecosystems. And since insects are crucial parts of all terrestrial food webs, their loss <a href="https://www.nationalgeographic.com/news/2017/08/insect-bug-medicine-food-macneal">affects many other organisms from plants to birds</a>.</p>
<h2>How we do our work</h2>
<p>Konza Prairie is a large protected prairie in northeastern Kansas, and researchers have been collecting data on the grasses, insects, and animals there since the early 1980s. My colleagues and I relied on this long-term data and physical samples from years past to perform our study. </p>
<p>Grasshopper numbers fluctuate on a roughly five-year cycle that follows changes in the climate, like the <a href="https://theconversation.com/what-north-america-can-expect-from-el-nino-51959">El Niño</a> Southern Oscillation. Having a decades-long data set allowed my colleagues and me to clearly separate these cycles from the long-term population decline and see how increasing CO2 levels played a part.</p>
<p>This kind of data is surprisingly rare, which has led to a good deal of controversy regarding the ubiquity of insect declines. Sites like the Konza Prairie (part of the NSF-funded <a href="https://lternet.edu/">Long-Term Ecological Research Network</a>) are on the front lines in documenting Earth’s changing ecosystems.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/318922/original/file-20200305-106584-15xc07.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/318922/original/file-20200305-106584-15xc07.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=489&fit=crop&dpr=1 600w, https://images.theconversation.com/files/318922/original/file-20200305-106584-15xc07.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=489&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/318922/original/file-20200305-106584-15xc07.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=489&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/318922/original/file-20200305-106584-15xc07.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=614&fit=crop&dpr=1 754w, https://images.theconversation.com/files/318922/original/file-20200305-106584-15xc07.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=614&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/318922/original/file-20200305-106584-15xc07.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=614&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Block print of a Showy grasshopper (<em>Hesperotettix speciosus</em>) eating a sunflower leaf.</span>
<span class="attribution"><span class="source">Ellen Welti</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>Nutrient dilution by CO2 is a compelling hypothesis for why widespread insect declines are happening. Our data jibes with other experiments that pump CO2 into ecosystems and <a href="https://doi.org/10.1111/j.1365-2486.2007.01392.x">drive down both plant nutrients and insect growth</a>.</p>
<p>But solid data on insect numbers over time is still quite rare, and there are still more questions than answers. How widespread is nutrient dilution in ecosystems worldwide? Are plant-feeding insects suffering the greatest declines? Which ecosystems will be hardest hit?</p>
<p>At present, we ecologists lack even basic population estimates for most of Earth’s invertebrate species, which comprise the vast majority of animal diversity.</p>
<p>I suspect that if nutrient dilution by CO2 is indeed widespread, it will likely be affecting Earth’s ecosystems and organisms – including humans – for generations to come, at least as long as fossil fuels burn and CO2 levels continue to rise.</p>
<p>[<em>You’re smart and curious about the world. So are The Conversation’s authors and editors.</em> <a href="https://theconversation.com/us/newsletters?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=youresmart">You can read us daily by subscribing to our newsletter</a>.]</p><img src="https://counter.theconversation.com/content/133051/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Ellen Welti receives funding from the National Science Foundation (NSF) Division of Environmental Biology (DEB) grants 1556280 and 1440484.</span></em></p>Insect populations are falling as what they eat becomes more like iceberg lettuce and less like kale.Ellen Welti, Postdoctoral Researcher of Biology, University of OklahomaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1164802019-05-15T23:20:19Z2019-05-15T23:20:19ZGive bees a chance: We can’t afford to lose our wild native pollinators<figure><img src="https://images.theconversation.com/files/273170/original/file-20190507-103063-1w18isx.JPG?ixlib=rb-1.1.0&rect=0%2C0%2C4587%2C3435&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A bumblebee sips nectar from a clover.</span> <span class="attribution"><span class="source">Victoria MacPhail</span>, <span class="license">Author provided</span></span></figcaption></figure><p>A quintessential sign of spring is a busy bee happily buzzing from blossom to blossom. While spring is now in full swing across Canada, the presence of those dependable pollinators is becoming more and more uncertain. </p>
<p>Our <a href="https://www.savethebumblebees.ca">research team</a> is focused on assessing the status of wild pollinators, understanding the threats they face and working to conserve species at risk of extinction before it’s too late. </p>
<p>What we’ve learned about bee declines may surprise even the most avid nature lover. </p>
<h2>Canada’s bee diversity</h2>
<p>Pollinator declines have become one of the most talked about environmental issues. While media, policy and public discourse have focused on <a href="https://www.doi.org/10.1126/science.aau0152">neonicotinoid pesticides and the loss of European honeybees</a>, the story of bee decline is much more complex than that. </p>
<p>In Canada, we have more than 850 species of native bees, and the vast majority of those species have not been assessed to properly understand how they are faring in the wild. None of our native bees make honey. Most are solitary (that is they don’t live in hives), most live underground and many cannot sting. </p>
<p>They come in an array of colours including blue, metallic silver and green. Each of our native bee species has their own nesting and foraging needs. Some live in grasslands, others in forests. Some have adapted well to our urban, built environments. They each react to various threats differently. </p>
<h2>A bee is not a bee is not a bee</h2>
<p>While honeybees have their own management issues (including exposure to <a href="https://www.doi.org/10.1126/science.aam7470">neonicotinoids in agricultural landscapes</a>), we must understand that they are imported to North America for human benefit to produce honey and pollinate large farms. Some people keep honeybees as a hobby. They are not at risk of extinction and they can even <a href="https://doi.org/10.1111/cobi.12839">negatively impact wild bee populations and plant communities</a>. </p>
<p>The idea of promoting honeybees to conserve declining bees can be likened to throwing millions of Asian carp (an invasive species) into Lake Ontario to save native fishes — it’s a ludicrous proposition to conservationists. Instead, we must determine which wild bee species are in decline and what threats cause harm to their populations, and then design evidence-based conservation management plans to keep them from going extinct.</p>
<p>Recently, the <a href="https://www.iucn.org/ssc-groups/invertebrates/bumblebee">Bumblebee Specialist Group</a> for the <a href="https://www.iucn.org/">International Union for the Conservation of Nature</a> assessed the status of North America’s bumblebees (the best understood group of native bees). Startlingly, the group found one in four of our native bumblebees are at risk. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/274415/original/file-20190514-60570-1rwl4mo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/274415/original/file-20190514-60570-1rwl4mo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=444&fit=crop&dpr=1 600w, https://images.theconversation.com/files/274415/original/file-20190514-60570-1rwl4mo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=444&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/274415/original/file-20190514-60570-1rwl4mo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=444&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/274415/original/file-20190514-60570-1rwl4mo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=558&fit=crop&dpr=1 754w, https://images.theconversation.com/files/274415/original/file-20190514-60570-1rwl4mo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=558&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/274415/original/file-20190514-60570-1rwl4mo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=558&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A rusty-patched bumblebee collected in Wisconsin in the 1960s, when it was common.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/usgsbiml/32801122541">USGS</a></span>
</figcaption>
</figure>
<p>Some species, like the critically endangered <a href="https://www.iucnredlist.org/species/44937399/46440196">rusty-patched bumblebee</a>, have declined drastically over few decades. Growing evidence suggests <a href="https://doi.org/10.1002/ecy.2697">habitat loss</a>, <a href="https://www.doi.org/10.1126/science.aaa7031">climate change</a> and <a href="https://doi.org/10.1016/j.biocon.2005.11.013">disease spillover from managed bees</a> are the top threats to bumblebees. Recently, our lab found <a href="https://doi.org/10.1007/s10841-019-00152-y">the American bumblebee has declined by more than 85 per cent in recent decades</a> throughout its Canadian range of southern Ontario and Québec. If we are to conserve this and other species, we need to act quickly. </p>
<h2>Biodiversity for resilience and sustainability</h2>
<p>Keeping sustainable populations of wild bees should matter to every one of us, not just nature enthusiasts. Study after study confirms that maintaining our pollinator biodiversity keeps our <a href="https://doi.org/10.1098/rspb.2002.2306">agricultural systems</a> and <a href="https://doi.org/10.1111/j.1600-0706.2008.16819.x">natural ecosystems resilient</a>. When parasites like Varroa mites hit managed honeybees, <a href="https://doi.org/10.1111/j.1461-0248.2007.01110.x">wild bees provide insurance</a>, pollinating crops that otherwise may not produce food. </p>
<p>Wild bees pollinate our crops in rural areas, our residential vegetable gardens and even our rooftop gardens. These free pollination services translate directly into economic benefits for humans and <a href="https://www.doi.org/10.1126/science.1230200">contribute to local food security</a>. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/mite-versus-mite-the-search-for-an-effective-way-to-save-honeybees-108873">Mite versus mite: The search for an effective way to save honeybees</a>
</strong>
</em>
</p>
<hr>
<p>Wild bees also pollinate flowers, trees and shrubs, which in turn feed and shelter other native wildlife, provide flood control, prevent soil erosion and help regulate the climate. </p>
<p>Bees serve as an important example of how biodiversity provides free ecosystem services upon which humans and other wildlife rely. They are taken for granted, but if they disappear the consequences will be cascading and significant. </p>
<p>Recently, the United Nations prepared an <a href="https://www.ipbes.net/news/Media-Release-Global-Assessment">extensive report</a> synthesizing how biodiversity declines are leading to the loss of ecosystem services globally. Some governments, <a href="https://www.thespec.com/news-story/9337134-sweeping-changes-buried-in-housing-bill-called-doomsday-scenario-for-ontario-s-endangered-species/">including in Ontario</a>, have framed conservation as too costly an endeavour or as hindrance to development. This is short-sighted and does not consider the real costs of losing biodiversity. </p>
<p>We need transformational change for how we steward our private and public lands and how we value our natural ecosystems and wildlife. To better conserve our biodiversity, we need to create habitat big and small, whether in our <a href="https://wildlifepreservation.ca/a-flower-patch-for-the-rusty-patched/">city gardens</a> or large protected areas. </p>
<p>We need to fund basic science to better understand ecosystem processes and species interactions in a changing world. We need to demand sound policy based on evidence and use the precautionary principle where knowledge gaps exist. </p>
<p>We need to include Indigenous knowledge systems and consider future generations in decision-making. We need adults and children alike to observe the natural world and learn the names of local species. Citizen science projects such as <a href="https://www.bumblebeewatch.org">BumbleBeeWatch</a> are great ways to learn while helping scientists gather information.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/wonder-and-wisdom-in-a-childrens-forest-nature-program-106692">Wonder and wisdom in a children's forest nature program</a>
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</em>
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<hr>
<p>The solutions to “save the bees” and other native wildlife are complex and multi-faceted. </p>
<p>While out and about this spring, take a moment to notice that bumblebee sipping nectar from a flower. It is an interaction that is simple, but not inconsequential. </p>
<p>It offers us the opportunity to consider the intricate links between plants, humans, wildlife and the land that make our very way of life possible. It is up to us to do everything we can to ensure these connections remain strong not only for ourselves, but for future generations.</p><img src="https://counter.theconversation.com/content/116480/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Sheila R. Colla receives funding from NSERC, NFRF, Wildlife Preservation Canada and The W. Garfield Weston Foundation. </span></em></p><p class="fine-print"><em><span>Rachel Nalepa receives funding from The W. Garfield Weston Foundation </span></em></p>Wild bees pollinate trees and shrubs that feed and shelter wildlife, provide flood control, prevent soil erosion and help regulate the climate.Sheila Colla, Assistant Professor of Environmental Studies, York University, CanadaRachel Nalepa, Post-Doctoral Fellow, York University, CanadaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1117242019-04-30T22:06:40Z2019-04-30T22:06:40ZUrban bee keepers can help save wild bees<figure><img src="https://images.theconversation.com/files/268483/original/file-20190409-2918-1c2drvm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Urban beekeepers trained in native bee stewardship and pollinator gardening can help fight the decline of native bees.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><p>With <a href="https://doi.org/10.1371/journal.pone.0185809">reports of declining insect populations</a> worldwide, or what George Monbiot calls an “<a href="https://www.theguardian.com/commentisfree/2017/oct/20/insectageddon-farming-catastrophe-climate-breakdown-insect-populations">insectageddon</a>,” there is growing concern about the health of pollinators. This in turn has led to increasing interest in urban beekeeping, pollinator gardening and urban bee advocacy. </p>
<p>Yet there is also a <a href="https://www.facebook.com/NatureInTheCityTO/photos/a.157793427755142/851507241717087/?type=3&theater">growing backlash against urban honey bees</a>. Some native bee advocates argue that in North America, <a href="https://doi.org/10.1111/cobi.12839">honey bees, which were brought to the Americas by European colonialists, belong in the monocultured fields of industrial agriculture, where they are critical for crop pollination, not cities</a>.</p>
<p>As a political ecologist who researches the relationship between people and urban bees (both those that are managed and those that are wild), I am concerned about the growing antagonism between people who should be allies in the struggle against industrial agriculture. </p>
<h2>Are native bees and honey bees competitors?</h2>
<p>Some entomologists and native bee advocates are concerned that when managed honey bees and wild bees compete for sources of nectar and pollen, the wild bees lose.</p>
<p>Scientists studying the <a href="https://doi.org/10.1371/journal.pone.0189268">effects of managed bees on wild bees</a> have seen mixed results. A <a href="https://doi.org/10.1093/ee/nvy077">recent analysis</a> revealed that 10 of 19 experimental studies showed some evidence of competition between honey bees and wild bees, mostly in natural areas near agricultural fields.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/263176/original/file-20190311-86686-1bh4sku.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/263176/original/file-20190311-86686-1bh4sku.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/263176/original/file-20190311-86686-1bh4sku.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/263176/original/file-20190311-86686-1bh4sku.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/263176/original/file-20190311-86686-1bh4sku.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/263176/original/file-20190311-86686-1bh4sku.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/263176/original/file-20190311-86686-1bh4sku.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">
<figcaption>
<span class="caption">Honey bee hives on top of the Fairmont Royal York in Toronto. These hives are maintained by the Toronto Urban Beekeepers Collective.</span>
<span class="attribution"><span class="source">Rebecca Ellis</span></span>
</figcaption>
</figure>
<p>Most of these studies focus on naturalized landscapes in rural areas. Yet some native bee advocates promote the precautionary principle — the idea that if something is reasonably thought to cause harm, then it should be avoided. They argue that urban beekeeping shouldn’t be allowed.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-clean-is-your-city-just-ask-the-bees-113981">How clean is your city? Just ask the bees</a>
</strong>
</em>
</p>
<hr>
<p>Native bee advocates rightly call <a href="http://doi.org/10.1126/science.aar2269">honey bees livestock animals</a>. But the argument that follows — that their health is therefore not a conservation issue — is misguided. </p>
<h2>Honeybees in industrial agriculture landscapes</h2>
<p>The health of livestock animals, especially those that forage in the landscape, and the health of wild animals are deeply intertwined. Honey bees are deeply embedded in capitalist-industrial food systems, <a href="https://www.researchgate.net/publication/328786871_Where_have_all_the_flowers_gone_Honey_bee_declines_and_exclusions_from_floral_resources">which leaves them extremely vulnerable</a>.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/263185/original/file-20190311-86710-1q8uhk3.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/263185/original/file-20190311-86710-1q8uhk3.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/263185/original/file-20190311-86710-1q8uhk3.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/263185/original/file-20190311-86710-1q8uhk3.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/263185/original/file-20190311-86710-1q8uhk3.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/263185/original/file-20190311-86710-1q8uhk3.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/263185/original/file-20190311-86710-1q8uhk3.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">
<figcaption>
<span class="caption">Two wild bees on a Valerian flower.</span>
<span class="attribution"><span class="source">Rebecca Ellis</span></span>
</figcaption>
</figure>
<p>Honey bee numbers are not in decline because humans artificially breed them, rapidly replacing lost colonies. But honey bees are subject to a toxic soup of chemicals containing <a href="https://doi.org/10.1016/j.jinsphys.2016.01.001">insecticides</a>, <a href="https://dx.doi.org/10.3390%2Finsects10010020">fungicides</a> and <a href="https://doi.org/10.1111/eea.12694">herbicides</a>. </p>
<p>Like wild bees, honey bees also suffer <a href="https://doi.org/10.1016/j.jinsphys.2011.12.001">nutrient deficiencies</a> within the monocultured landscapes of industrial agriculture, and their <a href="https://doi.org/10.1038/srep32023">forced movement across landscapes</a> to provide pollination services subjects them to stress. This has led honey bees to <a href="https://doi.org/10.1038/nature12977">become infected with and spread</a> numerous pathogens to vulnerable wild bee populations. The biggest concern is that viruses spread by the <a href="https://doi.org/10.1073/pnas.1818371116">Varroa mite</a>, which is endemic to honey bees, may spread to wild bees.</p>
<h2>Sickly bees</h2>
<p>Commercial beekeeping practices mimic many of the practices associated with other intensively farmed animals of industrial agriculture. Queen bees are artificially inseminated, <a href="https://www.researchgate.net/publication/303873161_Status_of_breeding_practices_and_genetic_diversity_in_domestic_US_honey_bees">potentially narrowing genetic diversity</a>. Honey bees are fed highly processed sugar syrup and pollen patties, often derived from the corn and soy that dominates much of the North American rural landscape. They are treated with miticides to manage the Varroa mite and are given prophylactic antibiotics. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/mite-versus-mite-the-search-for-an-effective-way-to-save-honeybees-108873">Mite versus mite: The search for an effective way to save honeybees</a>
</strong>
</em>
</p>
<hr>
<p>Studies show that <a href="https://doi.org/10.1007/s11252-014-0403-y">honey bees</a> as well as <a href="https://doi.org/10.1603/0013-8746-101.6.1067">some wild species</a> flourish in cities. In urban landscapes all bees are less exposed to pesticides than they are on agricultural fields and <a href="https://doi.org/10.1002/ece3.1941">encounter a wider diversity of nectar and pollen</a>. </p>
<p>Urban beekeeping, which is largely a hobby, is not embedded within industrial agriculture, potentially allowing for more bee-centred practices. For example, hobbyist beekeepers could allow queens to mate naturally, use organic methods to deal with mites and allow bees to consume their own honey. Although voluntary surveys indicate that hobbyist beekeepers have higher colony losses than commercial beekeepers, this can change with appropriate support and education and may reflect more of a willingness to report losses.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/263183/original/file-20190311-86710-1gxjaam.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/263183/original/file-20190311-86710-1gxjaam.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=750&fit=crop&dpr=1 600w, https://images.theconversation.com/files/263183/original/file-20190311-86710-1gxjaam.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=750&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/263183/original/file-20190311-86710-1gxjaam.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=750&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/263183/original/file-20190311-86710-1gxjaam.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=943&fit=crop&dpr=1 754w, https://images.theconversation.com/files/263183/original/file-20190311-86710-1gxjaam.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=943&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/263183/original/file-20190311-86710-1gxjaam.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=943&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Urban honey bees on new comb. Toronto, ON.</span>
<span class="attribution"><span class="source">Rebecca Ellis</span></span>
</figcaption>
</figure>
<p>Urban honey bees are not currently needed for pollination in cities, but they are useful for the development of an ethical local food system. Honey from urban bees can provide a locally sourced, environmentally friendly sweetener, compared to <a href="https://doi.org/10.1016/j.cropro.2018.02.012">sugar cane</a> and <a href="https://doi.org/10.1021/acs.jafc.8b05672">sugar beets</a>. </p>
<h2>Stewards of native bees</h2>
<p>Urban beekeepers should be trained in native bee stewardship and pollinator gardening to help fight the decline of native bees. A friendly alliance between urban honey beekeepers and native bee advocates can also influence the practices of beekeepers, ensuring that they monitor their colonies for pests and pathogens and encouraging respect for wild bees in location selection.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/263187/original/file-20190311-86696-vfcusy.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/263187/original/file-20190311-86696-vfcusy.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/263187/original/file-20190311-86696-vfcusy.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/263187/original/file-20190311-86696-vfcusy.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/263187/original/file-20190311-86696-vfcusy.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/263187/original/file-20190311-86696-vfcusy.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/263187/original/file-20190311-86696-vfcusy.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">
<figcaption>
<span class="caption">A native pollinator garden at a school in London, Ont., planted by the author.</span>
<span class="attribution"><span class="source">Rebecca Ellis</span></span>
</figcaption>
</figure>
<p>Some native bee advocates seem to view the harmful effects of industrial agriculture on wild bees as a <a href="https://theconversation.com/wicked-problems-and-how-to-solve-them-100047">wicked problem too large and complex to solve</a>, so they focus on potential threats, like urban honey bees, that can be controlled. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-to-fight-insectageddon-with-a-garden-of-native-plants-90585">How to fight Insectageddon with a garden of native plants</a>
</strong>
</em>
</p>
<hr>
<p>Agrochemical corporations, in particular, have proven to be an extremely powerful foe, wielding influence in government bodies, but their power is not unstoppable. My research suggests that an <a href="https://doi.org/10.1080/10455752.2018.1494748">alliance between beekeepers, small-scale farmers and environmentalists can help several species flourish at once</a>. In cities, hobbyist beekeepers, native bee advocates and gardeners can form a similar bond by creating spaces of re-wilding while also increasing urban agriculture. </p>
<p>Instead of viewing wild and managed bees as being in competition, maybe we can view them as partners in producing landscapes of abundance.</p><img src="https://counter.theconversation.com/content/111724/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Rebecca Ellis receives funding from the Social Sciences and Humanities Research Council. She is affiliated with the Pollinator Pathway Project, the London Urban Beekeepers' Collective and is the chair of the city of London's Urban Agriculture Steering Committee. </span></em></p>Urban beekeeping is growing in popularity, but so is the backlash against honey bees.Rebecca Ellis, PHD Candidate, Western UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1158652019-04-24T08:54:54Z2019-04-24T08:54:54ZNuclear weapons might save the world from an asteroid strike – but we need to change the law first<figure><img src="https://images.theconversation.com/files/270542/original/file-20190423-175539-so185q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/download/success?u=http%3A%2F%2Fdownload.shutterstock.com%2Fgatekeeper%2FW3siZSI6MTU1NjA3NTAyNiwiYyI6Il9waG90b19zZXNzaW9uX2lkIiwiZGMiOiJpZGxfMTM1NDM0OTQ4IiwiayI6InBob3RvLzEzNTQzNDk0OC9tZWRpdW0uanBnIiwibSI6MSwiZCI6InNodXR0ZXJzdG9jay1tZWRpYSJ9LCIxMnhnUGR3WlVsUktvY0w2WUpMUWpkR01QWjAiXQ%2Fshutterstock_135434948.jpg&pi=33421636&m=135434948&src=U6VwZmCfK8h-NDpTQXZ8SQ-1-11">Shutterstock</a></span></figcaption></figure><p>The schlocky 1998 Bruce Willis movie <a href="https://www.imdb.com/title/tt0120591/">Armageddon</a> was the highest grossing film of that year. The blockbuster saw a master oil driller (Willis) and an unlikely crew of misfits place a nuclear bomb inside a giant asteroid heading for Earth, blow it up – and save humanity. Armageddon isn’t exactly a documentary: it’s packed full of sci-fi nonsense. But, 20 years on, its basic plot – of using a nuclear explosion to avert a cataclysmic asteroid collision – doesn’t seem quite as silly as it did at the time.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/kg_jH47u480?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<p>Major asteroid impact is a low-probability, but high-consequence risk to life on Earth. Large <a href="https://cneos.jpl.nasa.gov">“Near Earth Objects” (NEOs)</a> don’t hit Earth often, but it only takes one (just ask the dinosaurs – oh, wait, you can’t). Of course, low probability risks are easily dismissed, however high the consequences of them manifesting might be – and until recently the countries of the world largely viewed the threat posed by NEOs as something best left to Hollywood.</p>
<p>But that’s all changed, following the impact (in more ways than one) of the meteoroid that hit <a href="http://www.reuters.com/article/us-russia-meteorite-idUSBRE91E05Z20130215">Chelyabinsk in Russia in 2013</a>, which injured more than 1,000 people. Suddenly, the NEO threat became “real”, and major players – the US, Russia and the EU – all started pumping money into NEO preparedness, and developing formal strategies for response (see, for example, the production of the US’s first ever <a href="http://www.nasa.gov/sites/default/files/atoms/files/national_near-earth_object_preparedness_strategy_tagged.pdf">National Near-Earth Object Preparedness Strategy</a> in December 2016).</p>
<p>At the UN, we’ve recently witnessed the creation of an embryonic <a href="http://www.unoosa.org/oosa/en/ourwork/topics/neos/index.html">international institutional infrastructure</a> to detect and respond to asteroids. As part of all this – and in line with <a href="https://www.theatlantic.com/technology/archive/2013/10/the-plans-to-use-nuclear-weapons-to-blow-up-incoming-asteroids/280593/">increasing scientific opinion</a> – there is also a notable focus at governmental and intergovernmental levels on the use of nuclear weapons as our best hope. The US and Russia have even mooted working together on a <a href="https://energy.gov/articles/united-states-russia-sign-agreement-further-research-and-development-collaboration-nuclear">nuclear planetary defence initiative</a>. All of a sudden, it seems Bruce Willis and his team might be put on NASA’s speed-dial, after all.</p>
<h2>What the law says</h2>
<p>As a lawyer I can’t help but wonder how these recent developments sit with international law. Not well, it would seem. At the intersection of nuclear non-proliferation law and space law, various Cold War-era treaties would appear to rule out nuclear planetary defence. The legal picture is not always clear – the relevant law was drafted with the superpower arms race in mind, after all, not asteroids. But if a collision-course NEO was identified, it can at least be said that a proposed nuclear response would be very likely to violate international law. </p>
<p>For example, <a href="http://www.unoosa.org/pdf/publications/STSPACE11E.pdf">Article IV of the 1967 Outer Space Treaty</a> prohibits stationing nuclear weapons in space, which would apparently rule out nuclear NEO defence, at least if a nuclear defence system was located in space (rather than being launched from Earth).</p>
<p>The <a href="https://www.state.gov/t/isn/4797.htm">1963 Partial Test Ban Treaty</a> is an even bigger barrier for most states (although, notably, not all of the nuclear powers are party to it – but the US and Russia both are). Article I(1)(a) of that treaty prohibits “any … nuclear explosion … in … outer space”. And these are just the key treaties: there are a number of other possible legal hurdles, too. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/a-huge-asteroid-wiped-out-the-dinosaurs-but-what-danger-do-smaller-ones-pose-90133">A huge asteroid wiped out the dinosaurs, but what danger do smaller ones pose?</a>
</strong>
</em>
</p>
<hr>
<p>So what? If it came to a choice between legal niceties and saving humanity from extinction, there wouldn’t be much of a choice at all: law shouldn’t be a global suicide pact. Indeed, one nuclear power, Russia, has already <a href="http://www.telegraph.co.uk/news/worldnews/europe/russia/12103720/EU-Russia-may-nuke-asteroids.html">indicated</a> that – if that asteroid appeared – it likely would opt for “launch first, litigate second”.</p>
<p>But ignoring the law is always a dangerous business, and it’s not hard to envisage nuclear powers using the vague threat of “asteroids” as a pretext for developing new warheads, or even for launching nukes into space. And if they do so in unapologetic violation of international law, they’ll also circumvent all the checks and balances that the law can provide. That threat is maybe more worrying than the threat of some hypothetical space rock.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/270543/original/file-20190423-175535-1ww0a6e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/270543/original/file-20190423-175535-1ww0a6e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/270543/original/file-20190423-175535-1ww0a6e.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/270543/original/file-20190423-175535-1ww0a6e.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/270543/original/file-20190423-175535-1ww0a6e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/270543/original/file-20190423-175535-1ww0a6e.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/270543/original/file-20190423-175535-1ww0a6e.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">Earth’s saviour?</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/download/success?u=http%3A%2F%2Fdownload.shutterstock.com%2Fgatekeeper%2FW3siZSI6MTU1NjA3NTI2NSwiYyI6Il9waG90b19zZXNzaW9uX2lkIiwiZGMiOiJpZGxfOTQ2MDc2MzUiLCJrIjoicGhvdG8vOTQ2MDc2MzUvbWVkaXVtLmpwZyIsIm0iOjEsImQiOiJzaHV0dGVyc3RvY2stbWVkaWEifSwiL1pnbXQzM2thQ1dWZ2FuTmI1UlJXS0JDL1k0Il0%2Fshutterstock_94607635.jpg&pi=33421636&m=94607635&src=jeL5WSE2ePnRolUcPLAafw-1-24">Shutterstock</a></span>
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<p>In a <a href="https://repository.uchastings.edu/cgi/viewcontent.cgi?article=1831&context=hastings_international_comparative_law_review">major article</a> just published in the Hastings International & Comparative Law Review, I argue that international law needs to work out a way to thread this needle.</p>
<p>The law has to protect us from states using asteroids as a pretext for dodging nuclear disarmament obligations, or – gulp – nuclear aggression in space, while at the same time providing for a limited, safeguarded exception that would allow for multilateral nuclear planetary defence, should it ever come to pass that we need the “nuclear option” to save ourselves.</p>
<h2>A solution?</h2>
<p>As such, I propose either treaty amendment (or, more likely, the adoption of additional protocols) to carve out a new, bespoke legal exception for the use of nuclear weapons in space, in instances where a large collision-course NEO was identified and verified, and where the balance of independent scientific option clearly supported a nuclear response.</p>
<p>At the same time, to promote certainty, protect against abuse and increase the chances of success through the pooling of expertise and resources, I also argue for the creation of a new multilateral decision-making and oversight body, composed of all states (or as many states as possible), and which additionally included direct input from independently appointed scientific experts and organisations. </p>
<p>The aim is that the new body would be equipped both to stop countries misusing the new legal exception to develop militarised nuclear space programmes, while at the same time avoiding the deadlock issues associated with existing institutions (such as, for example, the UN Security Council) if humanity has to act quickly to avoid going the way of the dinosaurs. </p>
<p>All of this would be extremely complex (legally, politically and financially) and would take a huge amount of time to set up. But when it comes to the “asteroid threat”, time is not an issue. Until it is. So I suggest we get started now.</p>
<p>The political and scientific context has changed since 2013 but the legal context is still stuck in the thinking of the 1960s – and we need to update it. If we don’t, we really could risk Armageddon.</p><img src="https://counter.theconversation.com/content/115865/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>James A Green 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>Bruce Willis saved the Earth with a nuclear weapon in the 1998 film Armageddon, but the law would need to change for him to do it now.James A Green, Professor of Public International Law, University of ReadingLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1009122018-08-08T10:48:13Z2018-08-08T10:48:13ZWhy the summer sound of noisy crickets is growing fainter<figure><img src="https://images.theconversation.com/files/230232/original/file-20180801-136673-z77w1r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">shutterstock</span> </figcaption></figure><blockquote>
<p>Chirp, chirp!</p>
</blockquote>
<p>To make this familiar summer sound, the male cricket holds his nerve and “stridulates” – rubbing his back legs together in order to entice a female. He knows this makes him vulnerable. What a female cricket can find, so too can the predators and parasites that wish to consume or infect him. </p>
<p>Hiding in the vegetation, he is also surrounded by a silent audience of other males. Those “sneakier” males do not sing themselves, but will try to intercept females as they approach a singing rival. It is this dramatic scene that plays out as we hear the crickets and grasshoppers calling on warm evenings. Or at least it did.</p>
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<p>Because the crooning of the crickets has quietened in recent years and may be becoming a thing of the past. There is strong evidence that large numbers of crickets and grasshoppers (known, along with mantises, earwigs and cockroaches as the “Orthoptera”) are declining across Europe. <a href="http://ec.europa.eu/environment/nature/conservation/species/redlist/orthoptera/summary.htm?dm_i=2QBL,E62V,2KAHDP,1FRJW,1">A 2017 review of European species</a> showed that over 30% of the 1,000 European species were in decline while only 3% were increasing. As with many insects, we simply don’t know what is happening to most of the rest. </p>
<p>The problem is that recent work has suggested that all insect species, including Orthoptera, are declining – the so-called “<a href="https://theconversation.com/insect-armageddon-five-crucial-questions-answered-86171">insect Armageddon</a>”.</p>
<p>A 2017 study found that the abundance of flying insects has plunged by 75% over the past 25 years. One member of the study team, Professor Dave Goulson of Sussex University, said at the time: “Insects make up about two-thirds of all life on Earth [but] there has been some kind of horrific decline.” </p>
<p>He added: “We appear to be making vast tracts of land inhospitable to most forms of life, and are currently on course for ecological Armageddon. If we lose the insects then everything is going to collapse.”</p>
<p>Among the species threatened is the delightfully-named “wart-biter” – so-called because of an 18th century Swedish practice of using the strong jaws of the cricket to remove warts from the skin. The wart-biter is now the focus of conservation efforts, including reintroductions into sites from which it has been lost. But this kind of intensive conservation simply is not possible for all species.</p>
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<p>The reasons behind the decline in crickets and grasshoppers are the standard fare. The loss, damage and fragmentation of habitats, largely as a result of increasing farming and urbanisation, as well as increasing rates of fires such as those that the world is experiencing in 2018. Crickets are often held to be indicators of good quality natural habitat, so their decline mirrors the ongoing decline in the wider natural world. </p>
<h2>Noisy nature</h2>
<p>Anybody who has spent any time in the world’s most natural places will know that natural “soundscapes” are neither peaceful nor serene – they are as noisy and busy as any urban high street. The crickets are just one part of the larger soundscape that provides the musical accompaniment to nature’s play. Depending on where you live, you might hear bird song, flowing water, the buzzing of bees, the roar of tigers, the rustle of leaves, or the calling of frogs. </p>
<p>In 1962, Rachel Carson famously wrote about the “<a href="https://en.wikipedia.org/wiki/Silent_Spring">Silent Spring</a>” caused by the effects of agricultural pesticides on songbirds. Now we are beginning to appreciate that other components of the natural world are falling silent. This is why some scientists are turning to “soundscape ecology” or “ecoacoustics” as a tool to understand the changing natural world. </p>
<p>This new scientific field gives conservation biologists another tool – an ecological stethoscope with which to listen for subtle changes in the environment. But in order to protect the soundscape we need to protect the landscape. At a time when land is at a premium for food production, housing and industry, we need to make space for nature.</p><img src="https://counter.theconversation.com/content/100912/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Christopher Hassall 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>They’re just one of many insects facing dramatic population decline.Christopher Hassall, Lecturer in Animal Biology, University of LeedsLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/861712017-10-25T15:13:56Z2017-10-25T15:13:56ZInsect ‘Armageddon’: five crucial questions answered<figure><img src="https://images.theconversation.com/files/191862/original/file-20171025-25510-2h26iz.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">Shutterstock</span></span></figcaption></figure><p>Are we facing insect Armageddon? A <a href="http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0185809">recent study</a> found that German nature reserves have seen a 75% reduction in flying insects over the last 27 years. The researchers involved made stark warnings that this indicated a wider collapse of the general insect population that would bring about an ecological catastrophe if left unchecked.</p>
<p>But is this an over-dramatisation of a single study in one country, or is there some real cause for concern? Here we answer five questions about how important this result is and whether we should be worried.</p>
<h2>Does it matter if insect populations decrease?</h2>
<p>The idea of going out on a beautiful afternoon for a picnic and not having any wasps buzzing around might sound actually quite appealing, so why worry about insect decline? Well, besides annoying us, insects are a key link in many food chains. They are the main resources for many birds, small mammals, reptiles and other creatures.</p>
<p>They are also key for human food production, since many of our crops depend on insects for the pollination that leads to fruit and seed production. And insects play a very important role in decomposing organic matter, which allows nutrients to return to the soil and support the next year’s crops. So, in terms of insect’s ecological importance, a sharp decline in their abundance should be of great concern.</p>
<h2>Can we trust the methods of this study?</h2>
<p>Different from previous studies, this study monitored insect biomass. What this means is that we do not know what specific kinds of insects are declining (although the data collected will allow this analysis in the future). Nor do we know if all kinds of insects are declining equally. We also do not know if the problem is that insects are getting smaller or whether there are fewer of them.</p>
<p>But this approach provides a better estimate of the scale of the problem, even if it doesn’t show the specific details. For example, whether the insects are getting smaller or fewer in number, the decline would have just as big an impact on bird diets. <a href="https://link.springer.com/article/10.1007%2Fs10841-017-9972-4">Previous studies</a> looked mostly at one particular group of insects, and an argument about why a particular group was at risk overshadows the bigger question of whether this is a general problem. The new study suggests there is a very large, general problem.</p>
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<img alt="" src="https://images.theconversation.com/files/191795/original/file-20171025-25502-1g3vaux.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/191795/original/file-20171025-25502-1g3vaux.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/191795/original/file-20171025-25502-1g3vaux.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/191795/original/file-20171025-25502-1g3vaux.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/191795/original/file-20171025-25502-1g3vaux.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/191795/original/file-20171025-25502-1g3vaux.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/191795/original/file-20171025-25502-1g3vaux.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">Empty nest.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
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<h2>Are the results reliable?</h2>
<p>The study is the result of a collaboration with the Entomological Society of Krefeld – essentially made up of members of the public. This is a perfect demonstration of how we can collect much more data by involving interested members of the public, also known as “<a href="https://theconversation.com/uk/search?utf8=%E2%9C%93&q=citizen+science">citizen science</a>”. </p>
<p>Under current research funding models that usually only consider projects between one and five years in length, it’s not possible to run a university-based study for a project on this scale (64 locations over 27 years). So without the dedication of insect enthusiasts, we would not even know about this problem. </p>
<p>The data analysis was supported by a very good team of university scientists, so there should be no concern about the results. Instead we should consider whether the current funding models for research and the focus this creates can miss some crucial aspects of ecological science that have potentially very detrimental effects.</p>
<h2>What does a study in Germany mean to the rest of the world?</h2>
<p>There are no comparable studies in other countries so any discussion of whether the results are applicable elsewhere would be purely speculative. This is especially true because we don’t know the cause of the decline. </p>
<p>But there is plenty of evidence that supports the idea that insect populations are under threat globally. For example a 2014 study indicated a 45% decline in insect abundance on the majority of the <a href="http://science.sciencemag.org/content/345/6195/401">worldwide monitored locations</a>.</p>
<h2>What is the reason for the decline?</h2>
<p>The main problem with this study is that it does not help us find possible causes for such drastic decline. The researchers considered some aspects of vegetation and some climate variables, and neither seemed to be the main cause.</p>
<p>The fact that the decline was observed in nature reserves is particularly worrying, since it suggests that the decline might be even worse elsewhere. And the fact that we can detect the decline over a number of different reserves suggests that the cause isn’t just a localised event.</p>
<p>Possible answers include the industrial scale use of pesticides (which might not be as safe <a href="http://science.sciencemag.org/content/357/6357/1232">as previously thought</a>, or the increase in farms dedicated to a single crop and deforestation that is associated with this (which may not sustain as many insect species). The next step is to work out exactly what’s going on so we can attempt to reverse this worrying trend.</p><img src="https://counter.theconversation.com/content/86171/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Paula Kover 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>Researchers are warning of a wipeout of huge numbers of insects. What’s the evidence behind this alarm?Paula Kover, Reader in Biology and Biochemistry at The Milner Centre for Evolution, University of BathLicensed as Creative Commons – attribution, no derivatives.