tag:theconversation.com,2011:/us/topics/pine-trees-31783/articlesPine trees – The Conversation2023-10-26T13:38:18Ztag:theconversation.com,2011:article/2157322023-10-26T13:38:18Z2023-10-26T13:38:18ZA mystery disease hit South Africa’s pine trees 40 years ago: new DNA technology has found the killer<figure><img src="https://images.theconversation.com/files/555224/original/file-20231023-29-u8m533.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">An unidentified fungal killer swept through a South African pine plantation in the 1980s. </span> <span class="attribution"><span class="source">Rodger Shagam</span></span></figcaption></figure><p>In the 1970s and 1980s, pine trees growing in various forestry plantations in South Africa’s Western Cape province began to die in patches. These trees succumbed to a mysterious root disease and the patches expanded gradually. Spontaneous regrowth of seedlings in the patches died dramatically. </p>
<p>As in many other true crime dramas, the finger was initially pointed at the most likely suspect: the root-infecting <em><a href="https://pubmed.ncbi.nlm.nih.gov/28519717/">Phytophthora cinnamomi</a></em>. Its name – plant (phyto) destroyer (phthora) – reveals its power to cause harm; the pathogen is known to cause disease in almost 5,000 different plants.</p>
<p>After further investigation and the collection of many samples, tree pathologists shifted the blame onto the fungus <em>Leptographium serpens</em> (now known as <em>Leptographium alacre</em>). This fungus is well known to be transported by insects and was previously only known in Europe. It was visually identified from the roots of the dying trees. Now it was the prime suspect. </p>
<p>Doubts lingered, though. Most <em>Leptographium</em> species are not known to act as primary disease agents and so <em>L. serpens</em> was most likely not able to cause the disease. Other fungi were also found within the roots of the diseased trees but could not be identified at the time due to a lack of more advanced techniques.</p>
<p>Knowing that the then-available technologies could not provide the complete answer to this mystery, the pathologists took more samples from the dead and dying pine trees, and stored them carefully. The hope was that one day they would have a better idea of the cause of this disease outbreak. </p>
<p>Fast forward to 2023 and a new character enters the mystery: DNA sequencing. This modern technology did what wasn’t possible a few decades ago, allowing our team of molecular mycologists <a href="https://link.springer.com/article/10.1007/s42161-023-01502-1">to identify the real culprit</a>.</p>
<p>This tale is a testament to the ever-evolving nature of scientific inquiry. It reinforces the idea that, in the pursuit of knowledge, no stone should be left unturned and no assumption should be taken for granted. Through a blend of perseverance, technology, and a touch of serendipity, it was possible to solve a decades-old mystery.</p>
<h2>Tracking a killer</h2>
<p>Back in the 1980s the samples were stored in the culture collection of the <a href="https://www.fabinet.up.ac.za">Forestry and Agricultural Biotechnology Institute</a> at the University of Pretoria. In 2020, the samples were revived by a team that included ourselves and several others who recently <a href="https://link.springer.com/article/10.1007/s42161-023-01502-1">published a paper</a> on the topic. </p>
<p>We sequenced the samples’ DNA to reveal their unique genetic code. By comparing this code against genetic databases, it was possible to figure out exactly what was causing the tree disease. And so, more than four decades after the disease was first described, the pathogen was finally identified as <em>Rhizina undulata</em>. <em>L. serpens</em>, the long time primary suspect, was finally exonerated. </p>
<p><em>Rhizina undulata</em> is <a href="https://doi.org/10.1080/00382167.1984.9629524">well known</a> to cause tree disease and death, mainly in Europe. This fungus is known colloquially as the “coffee fire fungus” because the intense heat caused by fires made by campers in a forest to brew coffee activates its dormant spores. This allows it to colonise the roots of conifers, including pines. <em>R. undulata</em> is also well known in South Africa, where it kills many pines in the aftermath of forest fire and when trees are felled to clear a plantation.</p>
<p>What remains a mystery, however, is the trigger that activated this fungus in the Western Cape plantations. No fires were known to have occurred during the relevant time period.</p>
<p>One potential clue to the trigger may lie in the soil in which these trees were planted. Known as Table Mountain sandstone, this soil is sandy and acidic. Acidic soil <a href="https://doi.org/10.1016/S0007-1536(67)80014-7">has been shown</a> in the laboratory to encourage <em>R. undulata</em> growth. This naturally occurring acidity may have been the nudge the pathogen needed to infect the pine trees. It is also possible that the fungus was activated by heat radiating from the quartz rocks that are common in the areas in which the dying trees were planted.</p>
<h2>It pays to be patient</h2>
<p>In the years since the mysterious Western Cape outbreak, <em>R. undulata</em> has become well known to foresters in pine plantations in other parts of South Africa and has done great damage to newly planted trees after fires. These fires can be accidental or due to what is known as slash-burning after trees are harvested. </p>
<p>Identifying <em>R. undulata</em> as the culprit in those (no longer active) Western Cape plantations means scientists have more data that might help to better understand the biology of the fungus – which may lead to better control strategies in the future.</p>
<p>Our work is also a testament to the timeliness of scientific progress and the importance of patience. This story could only be fully unravelled when more advanced techniques were developed. It shows the power of modern technologies to solve historical problems. This underlines the need for continued investment into research and the development of new tools, both in South Africa and worldwide.</p>
<p>Our study also strongly advocates for the preservation of diverse fungal cultures for extended periods of time, regardless of their perceived importance at the time they are collected. The lack of accessible culture collections for lesser-known fungi, in South Africa and internationally, highlights the need for innovative approaches to safeguard these invaluable resources. This shift could revolutionise the study of microbes, opening new avenues beyond traditional species descriptions.</p><img src="https://counter.theconversation.com/content/215732/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Andi Wilson receives funding from the National Research Foundation through a Scarce Skills Postdoctoral Fellowship. </span></em></p><p class="fine-print"><em><span>Brenda Wingfield receives funding from South African Department of Science and Innovation. DSI-NRF SARChI chair in Fungal Genomics</span></em></p><p class="fine-print"><em><span>Michael John Wingfield has previously received Grant funding from the South African National Research Foundation and the Department of Science and Innovation as the director of the DSI/NRF Center of Excellence in Tree Health Biotechnology</span></em></p>Through a blend of perseverance, technology, and a touch of serendipity, it was possible to solve a decades-old mystery.Andi Wilson, Postdoctoral fellow, University of PretoriaBrenda Wingfield, Previous Vice President of the Academy of Science of South Africa and DSI-NRF SARChI chair in Fungal Genomics, Professor in Genetics, University of Pretoria, University of PretoriaMichael John Wingfield, Professor, Advisor to the Executive, University of Pretoria, University of PretoriaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1891432022-08-23T20:03:52Z2022-08-23T20:03:52ZLook up this spring – you might see little ravens build soft, cosy nests from your garden trees<figure><img src="https://images.theconversation.com/files/480504/original/file-20220823-14-kli3rl.jpg?ixlib=rb-1.1.0&rect=24%2C16%2C5398%2C3593&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>Spring is nearing and birds will soon start nesting in trees in backyards across Australia. The trees in our garden are now 40 years old – not old by tree standards, but old enough to be among the tallest in our suburb, offering refuge for local native birds.</p>
<p>When I propagated Monterey pine (<em>Pinus radiata</em>) seedlings for research in the mid 1970s, there were a few left over. I kept a couple, and one made a fine indoor Christmas tree for our young family in the early 1980s. My plan was to get rid of the tree but, after a few Christmases, the family was determined it would stay.</p>
<p>In the years since our tree, now in the garden, has grown to nearly 27 metres tall and almost 1m in diameter. It has become a favourite of many birds over the years and a nesting tree for <a href="https://australian.museum/learn/animals/mammals/common-ringtail-possum/">ring-tailed possums</a>. </p>
<p>A group of noisy but intelligent little ravens (<em>Corvus mellori</em>), have roosted in it, crowed from its lofty heights and battled others of the same and different species that have trespassed. </p>
<p>Over COVID lockdowns, I observed the curious behaviour of little ravens as they busily built their nests using the trees in my garden, and learned how they create a soft nest lining for their chicks. This spring you, too, can observe the delightful behaviour of birds as they visit your nearby trees and shrubs. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/480506/original/file-20220823-20-k5tduk.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/480506/original/file-20220823-20-k5tduk.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/480506/original/file-20220823-20-k5tduk.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=724&fit=crop&dpr=1 600w, https://images.theconversation.com/files/480506/original/file-20220823-20-k5tduk.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=724&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/480506/original/file-20220823-20-k5tduk.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=724&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/480506/original/file-20220823-20-k5tduk.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=910&fit=crop&dpr=1 754w, https://images.theconversation.com/files/480506/original/file-20220823-20-k5tduk.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=910&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/480506/original/file-20220823-20-k5tduk.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=910&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Monterey pine is native to the central coast of California and Mexico.</span>
<span class="attribution"><span class="source">Wikimedia commons</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<h2>Little ravens in backyards</h2>
<p>Monterey pine is an introduced species to Australia, and has significant potential to become <a href="https://www.conifers.org/pi/Pinus_radiata.php">a weed</a>, so we regularly check for self-sown seedlings. So far our vigilance has paid off and there are no escapees in the parks, gardens and surrounds. </p>
<p>While I would never recommend its planting, we are going to make the most of its presence while we have it. Over the years the tree has provided great summer shade and some wonderful interactions with local wildlife. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/cockatoos-and-rainbow-lorikeets-battle-for-nest-space-as-the-best-old-trees-disappear-165973">Cockatoos and rainbow lorikeets battle for nest space as the best old trees disappear</a>
</strong>
</em>
</p>
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<p>The din when sulphur-crested and yellow-tailed black cockatoos make their visits to feed on cones has to be heard to be believed. The cockatoos drive the little ravens away as they enjoy the cones, but the little ravens keep a look out and return as soon as the cockatoos have finished feeding. </p>
<p>During lockdowns the avian demands, discussion and negotiations were a welcome and entertaining break. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/480505/original/file-20220823-20-lor2fz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/480505/original/file-20220823-20-lor2fz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/480505/original/file-20220823-20-lor2fz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/480505/original/file-20220823-20-lor2fz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/480505/original/file-20220823-20-lor2fz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/480505/original/file-20220823-20-lor2fz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/480505/original/file-20220823-20-lor2fz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/480505/original/file-20220823-20-lor2fz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Yellow-tailed black cockatoo.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>Little ravens aren’t likely to rank high in the list of popular birds, but there is much to be impressed by when you study them. </p>
<p>Despite their name, little ravens aren’t actually that little, at over 40 centimetres tall. They are <a href="https://ebird.org/australia/news/identifying-australian-raven-and-little-raven-in-south-east-australia">common across southern Australia</a> and will eat almost anything, plant or animal. </p>
<p>They’re intelligent birds and great scavengers, capable of opening food containers, raiding bins and devouring road kill. They have adapted well to humans and so are found in backyards across the country. </p>
<h2>Building cosy nests</h2>
<p>Another special tree in our garden is the <a href="http://theconversation.com/stringybark-is-tough-as-boots-and-gave-us-the-word-eucalyptus-100528">messmate stringy bark</a> (<em>Eucalyptus obliqua</em>). I grew it and hundreds of others from seed for research experiments in the late 1970s, and it comes from the Wombat Forest near Daylesford, Victoria.</p>
<p>Its spreading canopy provides fine dappled summer shade. And it’s almost inconspicuous white flowers cause the tree to hum from the visits of local bees, not to mention the visits of native <a href="http://shyalbatrossyoungbirder.blogspot.com/2015/07/melbournes-commoner-honeyeaters.html">honey eaters</a>, such as the yellow wattlebird and the white plumed honeyeater.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/480508/original/file-20220823-18-xk4cat.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/480508/original/file-20220823-18-xk4cat.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/480508/original/file-20220823-18-xk4cat.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/480508/original/file-20220823-18-xk4cat.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/480508/original/file-20220823-18-xk4cat.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/480508/original/file-20220823-18-xk4cat.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/480508/original/file-20220823-18-xk4cat.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/480508/original/file-20220823-18-xk4cat.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Close-up of the <em>Eucalyptus obliqua</em> tree trunk.</span>
<span class="attribution"><span class="source">Wikimedia commons</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Every spring for about 20 years I had noticed marks on the tree’s branches, and wondered what caused them. During lockdown, I observed little ravens peeling strips of the fibrous stringy bark from upper branches. These are private, unannounced visits without calls or fuss. You had to be alert to know the birds were there.</p>
<p>Many birds are expert home decorators. The little ravens know exactly what they’re after and where to find it, and harvest nest-building material from different parts of the tree. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/stringybark-is-tough-as-boots-and-gave-us-the-word-eucalyptus-100528">Stringybark is tough as boots (and gave us the word 'Eucalyptus')</a>
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<hr>
<p>In their first visits, they gather material for the basic structure of the nest, made from twigs. Once in place, they strip long, coarse strings of bark from lower and larger branches in the canopy. </p>
<p>A few days later, the birds return to some of the younger upper branches where they collect fine, almost fur-like snippets of bark. These will provide an ideal fine soft inner nest lining for hatching raven chicks.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/480502/original/file-20220823-14-adj7cv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Little raven on a bin in a cemetary" src="https://images.theconversation.com/files/480502/original/file-20220823-14-adj7cv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/480502/original/file-20220823-14-adj7cv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/480502/original/file-20220823-14-adj7cv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/480502/original/file-20220823-14-adj7cv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/480502/original/file-20220823-14-adj7cv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/480502/original/file-20220823-14-adj7cv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/480502/original/file-20220823-14-adj7cv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Little ravens are expert scavengers.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>Observing birds in your own backyard</h2>
<p>From my work with trees, I have come to appreciate some of the delicate and intimate relationships between fauna and flora <a href="https://theconversation.com/the-ancient-intimate-relationship-between-trees-and-fungi-from-fairy-toadstools-to-technicolour-mushrooms-165974">and fungi</a>. </p>
<p>I look for evidence of possum claw marks on heavily grazed trees and the damage to branches caused by the nibbling of the powerful beaks of sulphur-crested cockatoos. Now, I know the long strands pulled from the upper trunks and larger branches of messmate stringy bark are due to the careful work of little ravens lining their nests. </p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-ancient-intimate-relationship-between-trees-and-fungi-from-fairy-toadstools-to-technicolour-mushrooms-165974">The ancient, intimate relationship between trees and fungi, from fairy toadstools to technicolour mushrooms</a>
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</em>
</p>
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<p>So at this time of the year, keep an eye out on both your garden plants and their avian visitors. </p>
<p>Look for birds darting, almost furtively, in and out of your trees, wisterias and rose bushes – they may have a nest within the foliage. Your prickly shrubs can afford protection to smaller birds and increase the chances of successful breeding.</p>
<p>Both native and introduced birds will be breeding in the next few weeks. And both native and introduced trees can be used by both for nesting. </p>
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<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/317999/original/file-20200302-18287-127mcmh.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/317999/original/file-20200302-18287-127mcmh.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=871&fit=crop&dpr=1 600w, https://images.theconversation.com/files/317999/original/file-20200302-18287-127mcmh.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=871&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/317999/original/file-20200302-18287-127mcmh.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=871&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/317999/original/file-20200302-18287-127mcmh.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1094&fit=crop&dpr=1 754w, https://images.theconversation.com/files/317999/original/file-20200302-18287-127mcmh.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1094&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/317999/original/file-20200302-18287-127mcmh.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1094&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"></span>
<span class="attribution"><span class="source">Wes Mountain/The Conversation</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
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<p>Many of popular garden trees – such as wattles or introduced conifers – can host magpies and silvereyes. If you live near a creek, you may attract the superb fairy wren in a bottlebrush. And different finches may occur in your gum trees, roses or wisterias.</p>
<p>Native tree and shrub species with diverse flowering times can be beneficial to our native birds. They provide nectar and host native insects species in late winter and deliver a full bounty of resources in spring. </p>
<p>Trees with fine foliage and fibrous bark, such as stringy bark and some of the feathery-leaved wattles, are popular with birds at this time of year for nesting material. </p>
<p>This means your garden can be an important way to maintain local biodiversity. In a changing climate, we need all the diversity we can get!</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/bandbs-for-birds-and-bees-transform-your-garden-or-balcony-into-a-wildlife-haven-129907">B&Bs for birds and bees: transform your garden or balcony into a wildlife haven</a>
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<img src="https://counter.theconversation.com/content/189143/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Gregory Moore 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>I watched little ravens line their nests with messmate stringy bark last spring. Here’s what birds might seek your garden trees this year.Gregory Moore, Senior Research Associate, School of Ecosystem and Forest Sciences, The University of MelbourneLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1849782022-06-30T13:36:21Z2022-06-30T13:36:21ZFollowing a fungus from genes to tree disease: a journey in science<figure><img src="https://images.theconversation.com/files/470094/original/file-20220621-11-g5ccgx.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">Pablo Rodriguez Merkel/Shutterstock</span></span></figcaption></figure><p>Anyone who reads even a little about science and technology will be familiar by now with the idea of <a href="https://www.genome.gov/about-genomics/fact-sheets/DNA-Sequencing-Fact-Sheet">genome sequencing</a>. This process involves breaking an organism’s DNA into fragments to study their compositions or sequences. Then the fragments are aligned and merged to reconstruct the original sequence.</p>
<p>But why sequence an organism’s genome? What’s the value for ordinary people and the world more broadly? The answers are immediately obvious when it comes to the medical field. Understanding what makes a disease “tick” offers scientists a way to treat or prevent it. Sequencing the genome of a crop or animal can improve agricultural yields or make species hardier in shifting climates.</p>
<p>It’s a little tougher to explain the value of sequencing the genome of plant pathogens, the organisms that cause diseases in plants. But this has become a critical part of the work of microbiologists and plant pathologists. And it is important, far beyond the laboratory: by carefully studying plant pathogens’ genomes, researchers have <a href="https://pubmed.ncbi.nlm.nih.gov/31993231/">been able to design</a> specific double stranded RNA fungicides to short circuit some pathogens’ abilities to harm plants. </p>
<p>These fungicides have not yet been deployed commercially but have huge potential – only targeted species will be affected and so the process is likely to be <a href="https://link.springer.com/article/10.1007/s42994-021-00036-3">more environmentally friendly</a> than any involving chemical fungicides. This research has the potential to protect crops, benefiting agriculture and contributing to food security.</p>
<p>For the past 13 years I’ve focused on sequencing one plant pathogen’s genome. Here’s where that scientific journey has led.</p>
<h2>Pine trees at risk</h2>
<p>I <a href="https://www.fabinet.up.ac.za/publication/pdfs/45-2012_wingfield_et_al_sa_j_of_science.pdf">sequenced the genome</a> of a fungus called <em>Fusarium circinatum</em> in 2009; it was the first fungal genome sequence to be conducted on the African continent. </p>
<p>I started studying this pathogen more than 20 years ago because it was killing seedlings in South African pine nurseries. <em>Fusarium circinatum</em> causes pitch canker on pine trees, which makes trees exude pitch or resin. In severe cases the fungus causes tree death. This fungus is considered to be the most important pathogen threat to the global plantation pine industry. It is also potentially devastating in some areas of the southern US, Central America, Europe and Asia, where pines are found naturally. </p>
<p>Trees are extremely important in carbon sequestration. They also produce oxygen – it is estimated that, daily, one tree can produce <a href="https://www.usda.gov/media/blog/2015/03/17/power-one-tree-very-air-we-breathe">enough oxygen for four people</a>. Trees have huge economic value, too, providing timber for our homes and paper and packaging for many uses in our daily lives. It is difficult to estimate the total value of pine plantations globally but the South African industry is estimated to contribute <a href="https://www.forestrysouthafrica.co.za/economic/">more than US$2 billion</a> to the country’s Gross Domestic Product annually. </p>
<p>Sequencing the genome was just the beginning. Follow-up studies <a href="https://www.sciencedirect.com/science/article/abs/pii/S1878614621000921?via%3Dihub">published</a> in <a href="https://www.sciencedirect.com/science/article/abs/pii/S1087184521000256">2021</a> involved knocking genes out of the genome and studying what happened. This process is a bit like first identifying and lining up all the parts, then removing these parts one at a time to see what difference they make to the functioning of the fungus. Sometimes we need to understand how gene products (proteins) interact with each other and then more than one gene might be removed from a genome. </p>
<p>In this way, my colleagues and I can learn which genes are important to the processes that <em>Fusarium circinatum</em> uses to cause pitch canker and which are not. Now we’re working to target the important genes in studies to manage the pathogen.</p>
<p>It’s time-consuming work: this fungus has around 14,000 genes. This is more than the yeast that is used to ferment beer, which has <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7099199/">6000 genes</a>, but less than the <a href="https://bmcbiol.biomedcentral.com/articles/10.1186/s12915-018-0564-x">estimated 25,000 genes</a> in the human genome. Luckily <a href="https://theconversation.com/what-is-crispr-the-gene-editing-technology-that-won-the-chemistry-nobel-prize-147695">technologies</a> are evolving rapidly to enable routine gene knock-outs. This involves a protein which acts a bit like DNA-specific scissors allowing deletion of a specific sequence of DNA. The position where the protein cuts is guided by using small pieces of RNA sequence that are identical to the target DNA sequence.</p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/what-is-crispr-the-gene-editing-technology-that-won-the-chemistry-nobel-prize-147695">What is CRISPR, the gene editing technology that won the Chemistry Nobel prize?</a>
</strong>
</em>
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<p>Another of our <a href="https://imafungus.biomedcentral.com/articles/10.5598/imafungus.2018.09.01.03">key findings</a> is that <em>Fusarium circinatum</em> has acquired, through horizontal gene transfer from other organisms, a group of five genes that apparently enhance its growth.</p>
<p>This discovery has been very useful in developing a specific diagnostic tool using LAMP PCR (Loop-mediated isothermal amplification) to identify this pathogen. This is a special kind of highly sensitive test that was developed to allow for in-field detection of pathogens. It also doesn’t require specialised training. This is useful because trees only recently infected with <em>Fusarium circinatum</em> can be asymptomatic. It’s crucial to determine the presence of the pathogen as early as possible so its spread can be better managed.</p>
<h2>New skills, new possibilities</h2>
<p>The rise in studies that sequence plant pathogens’ genomes has also opened up opportunities for scientists to develop new skills. The data generated by genome sequencing sometimes outstrips the number of researchers available to analyse it. During pandemic lockdowns in South Africa, some students in my research programme learned how to code and developed skills in bioinformatics, using computers to capture and analyse biological data rather than working in a laboratory.</p>
<p>With these new skills, as well as fast-improving technology, we may well crack <em>Fusarium circinatum’s</em> code once and for all. And that will help to guard pine trees against a dangerous, costly pathogen.</p><img src="https://counter.theconversation.com/content/184978/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Brenda Wingfield receives funding from the South African Department of Science and Innovation via the National Research Foundation (NRF).
She is a fellow of the Academy of Science of South Africa, African Academy of Science and the Third World Academy of Science
She is the Secretary General of the International Society of Plant Pathology and a fellow of the American Phytopathological Society
She is the current chair of the NRF Executive Evaluation Committee</span></em></p>For the past 13 years I’ve focused on sequencing one plant pathogen’s genome. Here’s where that scientific journey has led.Brenda Wingfield, Previous Vice President of the Academy of Science of South Africa and DSI-NRF SARChI chair in Fungal Genomics, Professor in Genetics, University of Pretoria, University of PretoriaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/821812017-09-11T19:59:23Z2017-09-11T19:59:23ZInvasive plants have a much bigger impact than we imagine<figure><img src="https://images.theconversation.com/files/185507/original/file-20170911-1336-1ovqssw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Invasive pine trees in the Western Cape have affected lizards causing their numbers to drop significantly.</span> <span class="attribution"><span class="source">Author supplied</span></span></figcaption></figure><p><em>This article is the fifth in a <a href="https://theconversation.com/africa/topics/invasive-species-series-39958">series</a> The Conversation Africa is running on invasive species.</em></p>
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<p>Most people would agree that <a href="http://www.iucngisd.org/gisd/">invasive plants</a> are unwanted. Invasive plants are plants that are intentionally or accidentally introduced by humans into areas outside of their natural habitat. These species can spread rapidly with negative consequences for native species. </p>
<p>Invasive plant species have an impact on the diversity of local species, they affect water availability and damage the quality of soil nutrients. Once an alien plant has invaded a habitat, it changes the conditions of that environment. It does so by changing the light, solar radiation and temperature levels in the invaded patches. The quality and availability of food, shelter, nest sites, basking sites and perches are changed for a number of animals. </p>
<p>They can also inflict big changes on native vegetation, altering the frequency of fires, nutrient cycling, water availability and soil erosion. For example, pine trees in the Western Cape Province of South Africa <a href="https://link.springer.com/article/10.1007/s00442-016-3726-y">have spread beyond forestry plantations and invaded</a> native fynbos habitat. In these invaded landscapes, the temperatures available to lizards for functioning optimally are generally cooler and the number of lizard species greatly reduced. </p>
<p>In a few cases, some benefits of alien plants have been reported. For example, they can provide fire wood for local communities or add resources for animal species. But these benefits typically do not surpass the negative effects. Invasive plants have an impact on native species through complex interactions and processes. Unless these factors are properly understood, it is difficult to predict what sort of impact invasive plants will have. </p>
<p>How much is known about these processes in South African habitats, where invasive alien plants are a key concern? To find the answer, we read all the studies on the impact of alien plant on animals that we could find from South Africa and presented these findings in <a href="http://www.abcjournal.org/index.php/ABC/article/view/2166">a recent study</a>. We focused on ectothermic animals (reptiles, amphibians and invertebrates), known as “cold blooded”. They <a href="http://www.nhc.ed.ac.uk/index.php?page=24.134.137.139">require heat exchange</a> from the environment to function, grow and reproduce. These animals typically move smaller distances than mammals or birds, which increase their vulnerability to alien plant invasions. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/185510/original/file-20170911-1327-wvoh0d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/185510/original/file-20170911-1327-wvoh0d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/185510/original/file-20170911-1327-wvoh0d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/185510/original/file-20170911-1327-wvoh0d.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/185510/original/file-20170911-1327-wvoh0d.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/185510/original/file-20170911-1327-wvoh0d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/185510/original/file-20170911-1327-wvoh0d.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/185510/original/file-20170911-1327-wvoh0d.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Alien vegetation has shaded Nile crocodile nests which are much cooler than normal sunny nests which female crocodiles prefer.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>A South African perspective</h2>
<p>Habitats that have invasive plants in South Africa have a poorer diversity of animal species than whole native habitats. There are multiple reasons for this poorer animal diversity, like reduced availability of food resources or thermal conditions that are essential for animal survival. These effects can also occur in tandem or accumulate in time and space. This echoes similar findings in other regions <a href="http://onlinelibrary.wiley.com/doi/10.1111/j.1461-0248.2011.01628.x/abstract">of the world</a>. There are however many gaps. </p>
<p>Existing studies focus on a few areas of South Africa and look at a small number of alien plants including Acacia, Hakea and Pinus species. Most studies examine the impact of alien plants on invertebrates, especially insects, but we have little data of how they impact reptiles and amphibians. South Africa is unique in its numbers of endemic <a href="http://www.tandfonline.com/doi/abs/10.1080/02541858.1995.11448377">tortoises</a>, lizards, <a href="http://sarca.adu.org.za/index.php">snakes</a> and <a href="http://sarca.adu.org.za/safap/index.php">amphibians</a>. But there are not many <a href="http://link.springer.com/article/10.1007/s00442-016-3726-y">studies</a> that address these species.</p>
<p>A nice example of how alien plants impact native animals comes from a <a href="http://www.sciencedirect.com/science/article/pii/S0006320700001774">study</a> in Lake St. Lucia, on the eastern part of South Africa. Alien vegetation has shaded Nile crocodile nests. Since being invaded, nests are much cooler than normal sunny nests which female crocodiles prefer. Temperature dictates the sex of embryos in reptiles, so this finding implies that development of eggs under these conditions will result in more females. These nest temperature changes could therefore affect the population’s demographics in the long-term and alter higher levels of organisation, like communities and species. So, invasive plant species might affect the environment in more ways than we can imagine.</p>
<p>The Nile crocodile study and <a href="http://www.sciencedirect.com/science/article/pii/S000632071200328X">a few other studies</a> in South Africa are the exception rather than the rule. Most attention to date has gone into comparing numbers of species or individuals between native and invaded areas rather than investigating how these changes take place. Most authors report about the potential impact invasive plants have but very few actually test potential causes of these impacts. </p>
<p>This gap is possibly because of the difficulty to experimentally test the ways these impacts develop or record data in the long-term. For example, monitoring and collecting data on native species in the long run would enable comparing processes before and after an alien plant invasion has taken place. </p>
<h2>Where to now?</h2>
<p>Without understanding what causes the potential impact these aliens plants can have, we cannot project the impact of introduced alien species into new regions or into the future. Management practices need to be shaped by the knowledge of these causes. <a href="http://www.ladybird-survey.org/">Scientists and citizens</a> can keep a fairly good record of newly introduced invasive plant species and the spread of established ones. </p>
<p>It becomes a huge challenge to keep comprehensive records of the ways alien plants affect local plants and animals. This difficulty is mostly because <a href="http://www.sciencedirect.com/science/article/pii/S0169534712001747">these processes</a> are often multiple and can change across time and geographic regions. </p>
<p>So, we face a challenge to capture these processes. But in an era of <a href="http://www.nature.com/nature/journal/v498/n7453/full/498255a.html">big data</a>, <a href="http://www.sciencemag.org/careers/2014/06/give-and-it-will-be-given-you">data sharing</a>, cross-country collaborations and <a href="http://science.sciencemag.org/content/343/6178/1436">public participation</a>, it is a task that can be handled.</p><img src="https://counter.theconversation.com/content/82181/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Susana Clusella-Trullas receives funding from National Research Foundation, South Africa. </span></em></p><p class="fine-print"><em><span>Raquel A Garcia receives funding from the Centre of Excellence for Invasion Biology (CIB). </span></em></p>Invasive plants have an impact on native species and unless these factors are properly understood, it is difficult to predict what sort of impact invasive plants will have.Susana Clusella-Trullas, physiological ecologist at the C·I·B, Stellenbosch UniversityRaquel A Garcia, Postdoctoral fellow at the CIB, Stellnbosch University, Stellenbosch UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/794442017-06-22T13:20:06Z2017-06-22T13:20:06ZInvasive species have a massive impact, but wise policy can keep them out<figure><img src="https://images.theconversation.com/files/174706/original/file-20170620-30812-1yhyxff.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The American red swamp crayfish was intentionally introduced to parts of Africa to control snails and as a pet.</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p><em>This article is the second in a <a href="https://theconversation.com/topics/invasive-species-africa-40566">series</a> The Conversation Africa is running on invasive species</em></p>
<p>Invasive alien species harm ecosystems, economies and human health across the globe. In Africa, alien trees <a href="http://www.sciencedirect.com/science/article/pii/S0921800907006167">reduce water yield</a> in regions that are severely water stressed. Fishes introduced for aquaculture <a href="http://www.nationalgeographic.org/media/impact-invasive-species/">reduce native biodiversity</a> and alien whiteflies spread <a href="http://www.apsnet.org/publications/apsnetfeatures/Pages/cassava.aspx">diseases in cassava</a> that can lead to famine.</p>
<p>Many of these species were introduced intentionally for use as pets, crops, livestock, garden plants or for forestry. Overall trade between countries has greatly improved human welfare by giving access to useful species. In Africa, these intentionally introduced species include the food staples cassava and maize, which are both native to the Americas.</p>
<p>But the continent has learned the hard way. A subset of imported species have become invasive, and by the time they become established in the wild it’s almost always too late to eradicate them. </p>
<p>More species than ever are being moved intentionally around the world as the pace of trade between countries continues to grow. Most countries still operate with what is essentially an open door policy, allowing in any species that commercial interests want to import.</p>
<p>But there is a better way. Invasive alien species are different from alien species that don’t cause harm. Scientists have the techniques and the know how to track these differences and to predict which species are likely to become invasive in the future. This makes it possible to decide wisely which species are safe to import. The impact of invasive species can be massively reduced if policies are developed based on these insights.</p>
<p>Developing these policies would be financially and environmentally beneficial for all countries. But there are significant challenges to implementation, particularly in developing countries, where resources for assessing species and then monitoring borders are scarce. These challenges could be overcome by sharing the results of assessments on species among countries, and through cooperation between importing and exporting nations to prevent the transport of harmful ones.</p>
<h2>A basic biology</h2>
<p>It’s possible to predict the behaviour of species by looking at their basic biology, how they interact with the environment, and how they spread. Using basic analysis, it’s possible to predict which invasive species will be bad, and which benign.</p>
<p>Not all are bad. Take the mollusc populations of the US Great Lakes which is home to a number of alien snails and mussels. But only a few are harmful – like the notorious zebra mussel which causes hundreds of millions in damage by clogging pipes and has fundamentally rearranged the Great Lakes ecosystems.</p>
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<a href="https://images.theconversation.com/files/174734/original/file-20170620-30863-wk24dl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/174734/original/file-20170620-30863-wk24dl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/174734/original/file-20170620-30863-wk24dl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/174734/original/file-20170620-30863-wk24dl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/174734/original/file-20170620-30863-wk24dl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/174734/original/file-20170620-30863-wk24dl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=504&fit=crop&dpr=1 754w, https://images.theconversation.com/files/174734/original/file-20170620-30863-wk24dl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=504&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/174734/original/file-20170620-30863-wk24dl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=504&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Zebra mussels, an invasive species of fresh water mussels, on the propeller and shaft of a
sailing yacht.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>This and other harmful non-native molluscs in the Great Lakes are characterised by having <a href="https://www.researchgate.net/profile/David_Lodge4/publication/6505938_Fecundity_as_a_Basis_for_Risk_Assessment_of_Nonindigenous_Freshwater_Molluscs/links/53dab7350cf2631430cb10a8.pdf">much higher production of offspring</a> than their harmless counterparts. </p>
<p>And in South Africa, <a href="https://www.researchgate.net/profile/Richard_Cowling/publication/227677415_Assessing_the_risk_of_invasive_success_in_Pinus_and_Banksia_in_South_African_mountain_fynbos/links/56fd3ec708ae3c85c0c9bf8e.pdf">invasive pine trees</a> mature faster and produce small seeds that can be blown long distances to colonise new habitats. These harmful pines are out competing native species in some habitats, while species without these characteristics rarely spread from where they’re planted.</p>
<p>Alien species with a history of being harmful in one area are likely to <a href="https://www.researchgate.net/profile/Keith_Hayes2/publication/225567176_Are_there_any_consistent_predictors_of_invasion_success_Biol_Inv/links/00b49532d0d139e018000000.pdf">cause harm in another</a>. </p>
<p>Transferring this scientific knowledge to policy helps to make predictions about how imported species are likely to act in the future. Risk assessment tools have been developed to do this. Some countries -– notably <a href="http://www.environment.gov.au/biodiversity/wildlife-trade/live">Australia</a> and <a href="https://www.mpi.govt.nz/law-and-policy/legal-overviews/biosecurity/">New Zealand</a> -– have been implementing these for over a decade. They ban all species that have the characteristics of invaders, including most reptiles. </p>
<p>Many others, including the US, European Union, and South Africa, are moving in this direction. But progress is slow and there is opposition from companies concerned about regulations that restrict what they can buy and sell.</p>
<h2>Policy is crucial for developing nations</h2>
<p>Progress has been made in managing the import of species in developed countries, but there’s been less in developing nations. Poorer countries face big challenges in, for example, developing policies and monitoring borders. </p>
<p>But developing nations have the most to gain from keeping invasive species out because invaders have a big impact on agricultural production and fisheries that make up a large portion of their economies. For example, the American <a href="http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0104-64972015000100002">red swamp crayfish</a> was intentionally introduced to Africa to control snails and as a pet. But it soon escaped into the wild where it reduces harvests of aquatic plants and fishes, and can even destabilise dam walls with its burrowing. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/174735/original/file-20170620-30842-17av5i3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/174735/original/file-20170620-30842-17av5i3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/174735/original/file-20170620-30842-17av5i3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=896&fit=crop&dpr=1 600w, https://images.theconversation.com/files/174735/original/file-20170620-30842-17av5i3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=896&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/174735/original/file-20170620-30842-17av5i3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=896&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/174735/original/file-20170620-30842-17av5i3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1126&fit=crop&dpr=1 754w, https://images.theconversation.com/files/174735/original/file-20170620-30842-17av5i3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1126&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/174735/original/file-20170620-30842-17av5i3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1126&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The red swamp crayfish escaped into the wild where it can reduce harvests of aquatic plants and fishes.</span>
<span class="attribution"><span class="source">Reuben Keller</span></span>
</figcaption>
</figure>
<p>There are ways round the problem. Developing nations can use simpler methods to determine which species are likely to become invasive. The US <a href="https://www.fws.gov">Fish and Wildlife Service</a> has developed a useful approach to <a href="https://www.fws.gov/injuriouswildlife/pdf_files/ERSS-SOP-Final-Version.pdf">risk assessment</a> that relies primarily on determining whether a species is suited to climates in the new region, and whether it has become invasive elsewhere. The assessment can be adapted for any region, applied to any plant or animal, and has reasonable accuracy. </p>
<p>Another way to reduce the cost is for countries to share predictions. This would mean that the burden of assessing species was spread out. </p>
<p>And better coordination between exporting and importing countries could help improve border controls and ensure compliance. </p>
<p>Policies that predict which species are likely to become invasive and then keep them out would have huge environmental and economic <a href="http://onlinelibrary.wiley.com/doi/10.1111/conl.12071/full">benefits</a>. South Africa is <a href="http://www.abcjournal.org/index.php/ABC/article/view/2136/0">developing regulations</a>. It should consider using one of the risk assessment approaches that have already been shown to be effective. </p>
<p>Other countries in sub-Saharan Africa need to take action too. Acting together, countries will be able to keep out the next invaders, protect biodiversity, reduce future financial costs, and lessen future losses of vital ecosystem services.</p><img src="https://counter.theconversation.com/content/79444/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Reuben P. Keller receives funding from United States Environmental Protection Agency.</span></em></p><p class="fine-print"><em><span>Sabrina Kumschick receives funding from the South African National Department of Environment Affairs through its funding of the South African National Biodiversity Institute’s Invasive Species Programme and from the DST-NRF Centre of Excellence for Invasion Biology. </span></em></p>Developing countries have been slow to react to the alien species problem. Its impact can be massively reduced if policies are developed to deal with the issue.Reuben P. Keller, Assistant Professor Freshwater Ecology, Invasive Species, Bioeconomics, Loyola University ChicagoSabrina Kumschick, Researcher and core team member Centre for Invasion Biology, Stellenbosch UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/658932017-04-18T02:14:13Z2017-04-18T02:14:13ZWhere the old things are: Australia’s most ancient trees<figure><img src="https://images.theconversation.com/files/165009/original/image-20170412-25888-1jhrjzu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Wollemia pine pollen cone. Wollemia pines (found in the wild only in Australia) are one of the most ancient tree species in the world, dating back 200 million years.</span> <span class="attribution"><span class="source">Velela/Wikipedia</span></span></figcaption></figure><p>They say that trees live for thousands of years. Like many things that “they” say, there is a germ of truth in the saying (even though it is mostly false). </p>
<p>The vast majority of trees that burst forth from seeds dropped on the Australian continent die before reaching maturity. In fact, most die within a few years of germination. </p>
<p>But depending on how you define a tree, a very select few trees can live for an astoundingly long time. </p>
<h2>What are the oldest trees?</h2>
<p>If we define a “tree” as a single stemmed woody plant at least two metres tall, which is what most people would <a href="https://www.anbg.gov.au/aust-veg/veg-map.html">identify as a tree</a>, then the oldest in Australia could be a <a href="http://www.theaustralian.com.au/life/weekend-australian-magazine/the-oldest-tree/story-e6frg8h6-1226130673929">Huon pine</a> (<em>Lagarostrobos franklinii</em>) in Tasmania, the oldest stem of which is up to 2,000 years old. </p>
<p>However, the Huon pine is also a clonal life form – the above-ground stems share a common root stock. If that common root stock is considered to be the base of a multi-trunked tree, then that tree could be as old as 11,000 years.</p>
<p>But if you accept a clonal life form as a tree, even that ancient Huon age pales into insignificance against the 43,000-year-old <a href="http://www.theaustralian.com.au/news/health-science/wild-australia-can-the-worlds-oldest-plant-be-saved/news-story/f568bf5ce8c5ea912d05f60c4dc72745">king’s holly</a> (<em>Lomatia tasmanica</em>), also found in Tasmania. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/163068/original/image-20170329-1642-9n0qxh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/163068/original/image-20170329-1642-9n0qxh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/163068/original/image-20170329-1642-9n0qxh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/163068/original/image-20170329-1642-9n0qxh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/163068/original/image-20170329-1642-9n0qxh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/163068/original/image-20170329-1642-9n0qxh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=755&fit=crop&dpr=1 754w, https://images.theconversation.com/files/163068/original/image-20170329-1642-9n0qxh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=755&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/163068/original/image-20170329-1642-9n0qxh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=755&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">King’s Holly, or Lomatia tasmanica, can form clones nearly 50,000 years old.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/40325561@N04/6501931867/in/photolist-7hXJbn-7hXJbp-qkuxzg-q44fUc-tgpki-b2jBok-7iKxUa-aUy6Pn-qdHSPX-qdHSUg-6Z8oAw-q44fCk-qdHSQi-7HoNsP-aUy6Pz-3gwZfc-tkEVN-a2UVCD-rcPoVu-pWHVGu-pWQk34-tkEUt-tkES6-qkjsqV">Natalie Tapson/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/">CC BY-NC-SA</a></span>
</figcaption>
</figure>
<p>Once you accept that a common, genetically identical stock can define a tree, then the absolute “winner” for oldest tree (or the oldest clonal material belonging to a tree) must go to the Wollemi pine (<em>Wollemia nobilis</em>). It may be <a href="http://www.abc.net.au/news/2014-09-21/secret-bid-to-save-prehistoric-wollemi-pines/5758542">more than 60 million years old</a>.</p>
<p>The Wollemi pine clones itself, forming exact genetic copies. It was thought to be extinct until a tiny remnant population was discovered in Wollemi National Park in 1994. The trunk of the oldest above-ground component, known as the <a href="http://www.wollemipine.com/faq.php">Bill Tree</a>, is about 400-450 years old. But the pine sprouts multiple trunks, so the Bill Tree’s roots may be more than 1,000 years old. </p>
<p>There is also substantial evidence that the tree has been cloning itself and its unique genes ever since it disappeared from the fossil record more than 60 million years ago. </p>
<h2>How do you date a tree?</h2>
<p>If no humans were around to record the planting or germination of a tree, how can its age be determined? The trees themselves can help tell us their age, but not just by looking at their size. Big trees are not necessarily old trees – they might just be very healthy or fast-growing individuals. </p>
<p>A much more reliable way to determine the age of a tree is through their wood and the science of <a href="https://en.m.wikipedia.org/wiki/Dendrochronology">dendrochronology</a> (tree-ring dating). </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/164987/original/image-20170412-26741-1ahi7f5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/164987/original/image-20170412-26741-1ahi7f5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/164987/original/image-20170412-26741-1ahi7f5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/164987/original/image-20170412-26741-1ahi7f5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/164987/original/image-20170412-26741-1ahi7f5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/164987/original/image-20170412-26741-1ahi7f5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/164987/original/image-20170412-26741-1ahi7f5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/164987/original/image-20170412-26741-1ahi7f5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Dendrochronology involves counting tree rings to date a tree. The wider the ring, the more water the tree absorbed in a given year.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/sheila/477734614/">sheila miguez/flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Many trees lay down different types of cell wall material in response to seasonal patterns of light, temperature or moisture. Where the cell walls laid down at the beginning of the growth season look different to those laid down at the end of the season, rings of annual growth can be seen in cross-sections of the tree. </p>
<p>This map of growth patterns can also be cross-dated or correlated with major events like multi-year droughts or volcanic eruptions that spewed material into the atmosphere to be incorporated into the wood of the tree. But the cell walls are more than just calendars.</p>
<h2>Why so old?</h2>
<p>Individual tree stems can live for so long because of the structure of the wood and the tree’s defence mechanisms. The woody cell walls are very strong and resist breakage. </p>
<p>In fact, scientists have recently discovered that these walls contain a structure – <a href="https://www.newscientist.com/article/mg21528786-100-why-wood-pulp-is-worlds-new-wonder-material/">nanocrystalline cellulose</a> – that is currently the strongest known substance for its weight.</p>
<p>Wood can, however, be broken down by insects and fungi. Even though there is little nutrition or energy in wood, there is some – and there are plenty of organisms that will try to use it.</p>
<p>But trees are not defenceless. They can fight back with physical barriers or even chemical warfare. When one tree is attacked by these destructive forces, individuals may even <a href="http://www.abc.net.au/science/articles/2015/05/20/4236600.htm">signal to other trees</a> to be aware and prepare their own defences to fight off death and decay.</p>
<h2>The death of trees</h2>
<p>So why don’t all trees live for centuries or millennia, and why do so many die before even reaching maturity? </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/165014/original/image-20170412-25859-1crgl1c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/165014/original/image-20170412-25859-1crgl1c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/165014/original/image-20170412-25859-1crgl1c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=792&fit=crop&dpr=1 600w, https://images.theconversation.com/files/165014/original/image-20170412-25859-1crgl1c.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=792&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/165014/original/image-20170412-25859-1crgl1c.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=792&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/165014/original/image-20170412-25859-1crgl1c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=996&fit=crop&dpr=1 754w, https://images.theconversation.com/files/165014/original/image-20170412-25859-1crgl1c.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=996&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/165014/original/image-20170412-25859-1crgl1c.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=996&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Adult Wollemi pines in the wild.</span>
<span class="attribution"><span class="source">J.Plaza/Van Berkel Distributors</span></span>
</figcaption>
</figure>
<p>Seedlings and young trees may die because they have germinated in an area where there’s not enough water, nutrients or light to keep them alive as adults. Young trees also haven’t had much time to develop barriers or defences against other organisms and may be browsed or eaten to death. </p>
<p>Some trees simply fall prey to accidents: wind storms, fires or droughts. This is just as well, because a vast number of plants and animals – including humans – rely on the wood and other components of these dead trees for their food and shelter. </p>
<p>But increasingly we may see trees dying because the environment is changing around them and they may not be able to cope. This is not just <a href="http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate3126.html">due to climate change</a>, but also to urban development and agricultural expansion, pollution and even too much fertiliser acting as a poison. <a href="http://www.myxyz.org/phmurphy/dog/DisturbanceDiversityInvasion.pdf">Even our most remote environments are subject to these changes</a>.</p>
<p>But that doesn’t necessarily mean we will have no more very old trees. The Wollemi pine’s genes have already survived over millions of years, multiple ice ages and warming periods and even the fall of the dinosaurs and rise of humans. And now,
people have deliberately spread Wollemi pine trees all around the world, so they are living in a wide range of countries and climates. This means that the risk of them all dying out is substantially reduced. </p>
<p>Maybe we can <a href="http://www.sciencedirect.com/science/article/pii/S0378112715000729">do the same for other trees</a>, ensuring that trees will outlive us all.</p><img src="https://counter.theconversation.com/content/65893/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Cris Brack is a member of the Institute of Foresters of Australia and Director National Arboretum, Canberra Foundation. </span></em></p><p class="fine-print"><em><span>Matthew Brookhouse 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>Australia is home to some of the oldest trees in the world. But how do they live so long?Cris Brack, Assoc Professor Forest measurement & management, Australian National UniversityMatthew Brookhouse, Research fellow, Australian National UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/655122016-10-02T19:36:31Z2016-10-02T19:36:31ZProtecting biodiversity: people’s buy-in is as important as the science<figure><img src="https://images.theconversation.com/files/139884/original/image-20160930-9922-nmqtyg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">South Africa's Proteaceae family, makes up a part of fynbos, a floral region with plants unique to South Africa Cape Town's Table Mountain National Park.</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>Biodiversity, the variety of life on earth (plants, animals and the ecosystems in which they live), underpins the planet’s life support systems and consequently human well-being. Unprecedented, large-scale biodiversity loss currently threatens the sustainability of these systems, such as the sustained supply of clean water.</p>
<p>As part of a global response numerous international agreements provide road maps for effective and urgent action. For example 196 countries, as signatories to the <a href="https://www.cbd.int/convention/">Convention on Biological Diversity</a>, have agreed to a set of targets that would contribute to slowing the loss of biodiversity globally. But conserving biodiversity is not enough. Focus is also needed on restoring damaged and degraded habitats. </p>
<p>South Africa has <a href="https://www.cbd.int/doc/strategic-plan/targets/T15-quick-guide-en.pdf">committed to</a> restore at least 15% of degraded ecosystems by 2020. The complex task of getting the job done has begun. But as with most things, the devil is in the detail.</p>
<p>Conservation success has a great deal to do with understanding the biology of habitats and species. But it is also about understanding the role that people play in the landscape, and the values they hold. </p>
<p>These issues tend to erupt where urban areas interface with nature, because the boundaries are unpredictable and risky and involve many competing views and values. </p>
<p>The polarised battle playing out in Tokai Park in the Western Cape is a microcosm of the world of potential conflict where natural environment interfaces with multiple social values. Here the tension is between those who want to remove pine trees to create space to restore a threatened indigenous plant community, and those who want the pine tree plantation to remain.</p>
<p>The Tokai Park debate, now in the realm of the courts, is a minor social issue in the context of the city. But it provides a window into the complex world of conservation where social issues intersect with ecology. So far efforts to find common ground have failed, highlighting how important it is to create conditions where opposing views can be debated, and common cause found in the fight to protect biodiversity. </p>
<h2>Two worlds collide</h2>
<p>Tokai Park is situated at the interface between urban development and one of the world’s most globally iconic habitats, <a href="http://www.southafrica.net/za/en/articles/entry/article-southafrica.net-south-africas-fynbos">fynbos</a> - a floral region with plants unique to South Africa. Tokai Park forms part of Cape Town’s Table Mountain National Park and is managed by <a href="https://www.sanparks.org/parks/table_mountain/about/2007/tokai.php">SANPARKS</a>, a national conservation agency.</p>
<p>The region is home to unparalleled <a href="https://www.iucn.org/content/world%E2%80%99s-hottest-hot-spot-plant-diversity">fynbos plant diversity</a> and has been identified as a global biodiversity hot-spot. It is also haven for a dwindling specialised habitat with nowhere else to go, <a href="https://www.capetown.gov.za/en/EnvironmentalResourceManagement/publications/Documents/Biodiv_fact_sheet_06_CapeFlatsSandFyn_2011-03.pdf">Cape Flats Sand Fynbos</a>. </p>
<p><a href="https://www.capetown.gov.za/en/EnvironmentalResourceManagement/publications/Documents/Biodiv_fact_sheet_06_CapeFlatsSandFyn_2011-03.pdf">Urbanization</a> has nearly wiped out Cape Town’s Cape Flats Sand Fynbos. The last critically endangered habitat is uniquely confined to the city of Cape Town. </p>
<p>South Africa has committed, through global targets and international agreements such as the <a href="https://www.cbd.int/convention/">Convention on Biological Diversity</a>, to protect and restore remaining natural habitats. And the remnants of this, and other threatened habitats, have been a focus of conservation attention for the local conservation agencies. </p>
<p><a href="https://www.facebook.com/ParkscapeSA/?fref=ts">Parkscape</a>, a Cape Town community group, recently mobilised enough support to temporarily prevent conservation authorities from maintaining a pine plantation in the specialised habitat.</p>
<p>Pines have been planted in the Cape over centuries. But their competitive dominance over fynbos and their water-guzzling ways have made them uncomfortable conservation companions.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/139889/original/image-20160930-9888-a6upb8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/139889/original/image-20160930-9888-a6upb8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/139889/original/image-20160930-9888-a6upb8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=408&fit=crop&dpr=1 600w, https://images.theconversation.com/files/139889/original/image-20160930-9888-a6upb8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=408&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/139889/original/image-20160930-9888-a6upb8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=408&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/139889/original/image-20160930-9888-a6upb8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=513&fit=crop&dpr=1 754w, https://images.theconversation.com/files/139889/original/image-20160930-9888-a6upb8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=513&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/139889/original/image-20160930-9888-a6upb8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=513&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Pines in the Tokai park have a competitive dominance over fynbos and their water-guzzling ways have made them uncomfortable conservation companions.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>So the chance to return a pine stand at the end of its commercial lifespan to its former fynbos-diverse natural glory seemed like a win-win solution. </p>
<p>But a fierce, largely middle class, lobby has put its weight behind retaining the non-native pines. The two sides have gone to court to try and settle the matter.</p>
<p>The commercial pine plantation is used for riding horses, walking dogs and a picnic spot in the summer. The small, well-resourced group defending it has garnered enough support to stay the fate of the pine trees. </p>
<p>Exchanges on <a href="https://www.facebook.com/ParkscapeSA/?fref=ts">social media</a> provide an insight into the many ethical and moral values tied up in the <a href="https://www.facebook.com/FriendsOfTokaiPark/">issue</a>. </p>
<p>There are those who argue that the area will become a magnet for criminals, citing a murder that occurred in nearby fynbos. Others are sentimental about the forest because it’s where they find solace and shade. Both sides point to the fact that pines as well as fynbos are sources of value such as medicines and wood. </p>
<p>But some key questions need to be asked. These include: can shade be provided in alternative ways? The answer is certainly yes. Native trees can provide suitable shade too. How fair is it to associate all future crime with restored fynbos? Crime happens everywhere. Cape Flats Sand Fynbos may well be a victim of crime-by-association.</p>
<h2>A way out of the impasse</h2>
<p>It is clear that conservation agencies have difficulty doing their work when social conflicts erupt.</p>
<p>The answer lies in concerted action to work with people who hold alternative views. In doing so, and by acknowledging their views, commonality can often be found. </p>
<p>But how can this be achieved? </p>
<p>Conservation agendas will only be advanced if people engaged in conservation can navigate social-ecological spaces and engage with multiple, often conflicting values, to try and find common ground.</p>
<p>Our <a href="http://www.sun.ac.za/english/faculty/agri/conservation-ecology">teaching</a> and <a href="http://academic.sun.ac.za/cib/">research</a> at Stellenbosch University is focused on conservation in used environments. That means we think about applied problems that often require multiple perspectives to resolve. We expose our students to these multiple perspectives, sensitising them to the challenges of working in a social-ecological context. </p>
<p>But understanding how to conduct appropriate public participation requires more. </p>
<p>A blend of skills is needed, including public communication, conflict management and facilitation. But these are difficult to incorporate into science-based degrees. Training opportunities need to be scaled up as well as innovative interdisciplinary collaboration. </p>
<p>Ecological restoration brings with it a message of hope. By repairing habitat suited to other living organisms, the services provided by these habitats are also returned to us. But unless we can convince the people of its value, and mediate surrounding conflicts, we are doomed to fail.</p><img src="https://counter.theconversation.com/content/65512/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Karen Joan Esler is affiliated with the DST NRF Centre for Invasion Biology at Stellenbosch University. </span></em></p>Restoring habitats have numerous benefits, they can also benefit humanity. But it is for people to be convinced that they can actually do good.Karen Joan Esler, Professor of Conservation Ecology and Head of the Department of Conservation Ecology & Entomology at Stellenbosch University, Stellenbosch UniversityLicensed as Creative Commons – attribution, no derivatives.