tag:theconversation.com,2011:/us/topics/land-mammals-27311/articlesland mammals – The Conversation2024-02-27T12:41:39Ztag:theconversation.com,2011:article/2191402024-02-27T12:41:39Z2024-02-27T12:41:39ZCould a couple of Thai otters have helped the UK’s otter population recover? Our study provides a hint<p>Otter populations crashed in Britain around the 1960s from the lethal effects of chemical pollution in rivers and lakes – or so we thought. <a href="https://academic.oup.com/mbe/article/40/11/msad207/7275014">Our research</a> has looked more closely at what happened to otters in Britain over the last 800 years and has revealed a more complex picture. </p>
<p>Since Eurasian otters (<em>Lutra lutra</em>) are at the top of the aquatic food chain in Britain, any contamination consumed by their prey, and by the prey of their prey, <a href="https://pubs.acs.org/doi/10.1021/acs.est.1c05410">accumulates in otters</a>. So otters are particularly susceptible to any toxic chemicals in their environment. </p>
<p>Following the banning of many chemical pollutants, otter populations began to recover, and we now have otters in <a href="https://onlinelibrary.wiley.com/doi/10.1111/eva.13505">every county in Britain</a>. National otter surveys have been conducted in Wales, Scotland and England since 1977 and have helped to track population recovery. </p>
<p>However, we didn’t have a good grasp on what population sizes were like in the decades before this time. We only had anecdotal evidence that otter hunting was becoming less “successful” over time, and that both sightings and signs of otters were rarer. </p>
<h2>Otter population decline</h2>
<p>Our research shows that roughly between 1950 and 1970, an extreme population decline happened in the east of England, and a strong decline in south-west England. They were probably caused by chemical pollution. </p>
<p>In Scotland, otter populations showed a long-term, but smaller decline, which suggests less chemical pollution. There was a smaller population decline in Wales, which started around 1800, possibly linked to otter hunting and changes in how people shaped and used the landscape. </p>
<p>While both deal with DNA, genetics focuses on individual genes and their roles, while genomics examines the entire set of an organism’s DNA. Although there have been genetic studies of otters in Britain, our research was the first time genomics was used to study Eurasian otters anywhere in the world.</p>
<p>Working with scientists from the Smithsonian Conservation Biology Institute and the Wellcome Sanger’s Darwin Tree of Life project, we looked at the entire otter genome. The upgrade from genetics to genomics threw up a few surprises. </p>
<p>First, there was a mitochondrial DNA sequence found in the east of England, which was very different to the sequences in the rest of Britain. Mitochondrial DNA is a sequence of DNA found in a cell’s mitochondria, which is what generates the energy. Mitochondrial DNA is inherited only from the mother, while the rest of the DNA is a mix of both the mother’s and the father’s DNA.</p>
<p>Another <a href="https://www.tandfonline.com/doi/full/10.1080/19768354.2023.2283763">recent study</a> by our research group, in collaboration with colleagues in South Korea, suggested a divergence between these two lineages at least 80,000 years ago. Finding this mitochondrial lineage (that, based on our data, is otherwise restricted to Asia) in the UK was surprising. </p>
<p>Second, we found high levels of genetic diversity in the east of England. Normally, after an extreme population decline such as the one we identified in this area, genetic diversity decreases. Yet we saw much greater diversity here than in the population in Scotland, where there was no clear evidence for such a decline. </p>
<h2>Thai otters</h2>
<p>With a little detective work, we discovered that a pair of Eurasian otters (the same species that we have in the UK), were brought to Britain from Thailand in the 1960s. Populations of Eurasian otters range right across Europe and Asia. Although they are the same species, there are several genetically distinct subspecies, particularly in Asia. </p>
<p>It seems possible that these genetically different otters from Thailand bred with otters in the east of England. At the time of the population decline, when native UK populations were at their smallest, even a few individuals introduced into the population may have made a big difference. And they left unexpected marks on the genome. </p>
<p>We don’t know for sure if this is what happened, and we need to do more work to find out what effect this may have had on otters in the east of England. High genetic diversity is usually good for a population or species. But on the other hand, conservation often strives to maintain genetic differences between populations, rather than mixing distinct populations.</p>
<p>One way to find out more would be to compare the genome of a Eurasian otter from Thailand to the otters we see in the east of England. Unfortunately, it’s not that easy. Since the 1960s, otters in Thailand and across Asia have become increasingly rare. This is due to habitat loss, pollution and the illegal otter trade. So getting samples for genome sequencing is very difficult. It highlights the importance of conserving the species in Asia, despite population recoveries in Europe.</p>
<p>Our work shows the value of using modern genomic tools to look at the genetic diversity of a threatened species. The application of such tools can uncover surprising facts, even in supposedly well-studied species.</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>Frank Hailer receives funding from NERC and Dŵr Cymru Welsh Water. </span></em></p><p class="fine-print"><em><span>Elizabeth Chadwick receives funding from the UK Natural Environment Research Council and from the Environment Agency</span></em></p><p class="fine-print"><em><span>Sarah du Plessis receives funding from the UK Natural Environment Research Council and the Global Wales International Mobility Fund.</span></em></p>Research has revealed how British otters may have been able to recover from species loss in the 1950s with the help of otters from Asia.Frank Hailer, Senior Lecturer in Evolutionary Biology, Cardiff UniversityElizabeth Chadwick, Senior Lecturer at the School of Biosciences, Cardiff UniversitySarah du Plessis, PhD Candidate, Cardiff UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1859652022-07-03T19:54:07Z2022-07-03T19:54:07ZResearch reveals fire is pushing 88% of Australia’s threatened land mammals closer to extinction<figure><img src="https://images.theconversation.com/files/472000/original/file-20220701-20-byxrpl.jpg?ixlib=rb-1.1.0&rect=6%2C6%2C4486%2C3166&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">David Mariuz/AAP</span></span></figcaption></figure><p>About 100 of Australia’s unique land mammals <a href="http://www.environment.gov.au/cgi-bin/sprat/public/publicthreatenedlist.pl?wanted=fauna">face</a> extinction. Of the <a href="https://www.pnas.org/doi/10.1073/pnas.1417301112">many threats</a> contributing to the crisis, certain <a href="https://www.environment.gov.au/cgi-bin/sprat/public/publicgetkeythreats.pl">fire regimes</a> are among the most pervasive.</p>
<p>In a <a href="https://conbio.onlinelibrary.wiley.com/doi/10.1111/conl.12905">new paper</a>, we reveal how “inappropriate” fire patterns put 88% of Australia’s threatened land mammals at greater risk of extinction – from ground-dwelling bandicoots to tree-climbing possums and high-flying microbats. </p>
<p>Our research also identifies what type of fires are most damaging to threatened mammals, and shows some mammals are suffering due to a lack of fire.</p>
<p>A better understanding of how inappropriate fire regimes damage mammal populations is crucial to addressing biodiversity loss and improving conservation efforts.</p>
<figure class="align-center ">
<img alt="dead koala lies amid scorched trees" src="https://images.theconversation.com/files/471999/original/file-20220701-16-ct4sbo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/471999/original/file-20220701-16-ct4sbo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/471999/original/file-20220701-16-ct4sbo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/471999/original/file-20220701-16-ct4sbo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/471999/original/file-20220701-16-ct4sbo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/471999/original/file-20220701-16-ct4sbo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/471999/original/file-20220701-16-ct4sbo.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">Changed fire patterns are among the most pervasive threats to Australian mammals.</span>
<span class="attribution"><span class="source">David Mariuz/AAP</span></span>
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</figure>
<h2>Understanding patterns of fire</h2>
<p>Fire is an important ecological process. Yet <a href="https://www.science.org/doi/10.1126/science.abb0355">human actions</a> – such as global heating, forestry and agriculture – are transforming fire activity in ways that challenge nature’s ability to cope.</p>
<p>“Inappropriate” fire regimes are those with patterns that drive biodiversity decline. </p>
<p>Fire patterns are made up of various components, including frequency, intensity, seasonality and size. But to date, there’s been no Australia-wide assessment of which components make a fire regime inappropriate for threatened species.</p>
<p>Our research set out to close this knowledge gap. It involved a comprehensive review of more than 400 research articles and <a href="http://www.environment.gov.au/cgi-bin/sprat/public/sprat.pl">policy documents</a> on fires and mammals, and taking a close look at the evidence linking the two.</p>
<p>To start, <a href="https://conbio.onlinelibrary.wiley.com/doi/10.1111/conl.12905">we identified</a> whether land mammals of conservation concern – those listed as critically endangered, endangered or vulnerable – were at risk from fire-related threats. We found that fire threatens 88% of these mammals.</p>
<p>Then we assessed the scientific evidence, such as field studies and expert opinion, to find out which fire components were in play. Contributing most to population declines were fires that are: intense and severe; large and extensive; and frequent. </p>
<p>Such a result might be expected. But significantly, we discovered these fire patterns are threatening species across the continent – from the arid interior to temperate forests in the south and tropical savannas to the north. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/australias-black-summer-of-fire-was-not-normal-and-we-can-prove-it-172506">Australia's Black Summer of fire was not normal – and we can prove it</a>
</strong>
</em>
</p>
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<img alt="person silhouetted against flames" src="https://images.theconversation.com/files/472001/original/file-20220701-26-edrm2i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/472001/original/file-20220701-26-edrm2i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/472001/original/file-20220701-26-edrm2i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/472001/original/file-20220701-26-edrm2i.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/472001/original/file-20220701-26-edrm2i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/472001/original/file-20220701-26-edrm2i.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/472001/original/file-20220701-26-edrm2i.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">Fires are threatening species across the continent.</span>
<span class="attribution"><span class="source">Dan Himbrechts/AAP</span></span>
</figcaption>
</figure>
<p>And our analysis went further, by identifying how these fire patterns may kill individual mammals and drive down populations.</p>
<p>Intense and severe fires usually generate a lot of heat and smoke, which can kill animals immediately or shortly afterwards. Such deaths are probably the cause of a decline in <a href="https://onlinelibrary.wiley.com/doi/10.1111/emr.12458">koala populations</a> after intense and severe bushfires in temperate forests, as well as the western ringtail possum and numbat. </p>
<p>Animals may also die in the weeks and months after a fire due to a lack of food and shelter – especially when large and extensive fires destroy habitat over a wide area.</p>
<p>This was likely the case for a species of <a href="https://doi.org/10.1071/ZO17041">antechinus</a> – a small mammal reliant on vegetation cover. Populations of swamp antechinus were considered extinct in some places after the large and severe Ash Wednesday fires in 1983 burned 40,000 hectares of heathy woodlands in southeast Australia.</p>
<p>In tropical savannas, <a href="https://doi.org/10.1016/j.biocon.2015.03.021">frequent and intense fires</a> affect reproduction of northern quolls, by reducing nesting resources and killing young in the pouch. </p>
<p>And some animals can suffer due to a lack of fire. For example, declines in some populations of northern bettongs may be due to long periods without fire which led to a decline in the <a href="https://doi.org/10.1071/BT10266">grasses</a> they eat.</p>
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<img alt="small mammal crouches below log" src="https://images.theconversation.com/files/471564/original/file-20220629-15-mh44vm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/471564/original/file-20220629-15-mh44vm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=391&fit=crop&dpr=1 600w, https://images.theconversation.com/files/471564/original/file-20220629-15-mh44vm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=391&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/471564/original/file-20220629-15-mh44vm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=391&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/471564/original/file-20220629-15-mh44vm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=491&fit=crop&dpr=1 754w, https://images.theconversation.com/files/471564/original/file-20220629-15-mh44vm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=491&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/471564/original/file-20220629-15-mh44vm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=491&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Northern quolls are affected by frequent, high-intensity fires.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>Fires are not the only threat</h2>
<p>But why do fires pose a threat to species that have evolved in a fire-prone landscape such as Australia? We believe it’s because several threatening processes, on their own and in combination, have reduced the size of mammal populations and affected their capacity to cope with fire. </p>
<p>For example, habitat loss and fragmentation means smaller populations of mammals are restricted to increasingly narrow geographic areas. This makes them more likely to be harmed by intense and large fires.</p>
<p>And when fire destroys vegetation cover, native animals are more vulnerable to being <a href="https://doi.org/10.1071/WR19027">hunted</a> by introduced species such as foxes and feral cats.</p>
<p>Climate change, grazing activity and weed invasion can also interact with fire to exacerbate mammal declines.</p>
<p>Importantly, fire regimes are also changing rapidly. The Black Summer fires of 2019-2020 – a disaster <a href="https://blog.csiro.au/bushfires-linked-climate-change/">intensified by climate change</a> – were unprecedented in terms of size and area severely burnt.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/this-critically-endangered-marsupial-survived-a-bushfire-then-along-came-the-feral-cats-185133">This critically endangered marsupial survived a bushfire – then along came the feral cats</a>
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</p>
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<img alt="aerial view of smoke billowing from Australia's east coast" src="https://images.theconversation.com/files/472002/original/file-20220701-22-lw7mpm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/472002/original/file-20220701-22-lw7mpm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/472002/original/file-20220701-22-lw7mpm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/472002/original/file-20220701-22-lw7mpm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/472002/original/file-20220701-22-lw7mpm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/472002/original/file-20220701-22-lw7mpm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/472002/original/file-20220701-22-lw7mpm.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">The Black Summer fires were unprecedented.</span>
<span class="attribution"><span class="source">NASA</span></span>
</figcaption>
</figure>
<h2>Towards better conservation</h2>
<p>Linking changes in mammal populations to the characteristics of fire regimes will help develop more effective conservation actions and policies.</p>
<p>For example, restoring <a href="https://doi.org/10.1016/j.biocon.2018.01.008">Indigenous fire practices</a> is likely to promote cooler, patchier fires that retain habitat refuges and boost food resources for ground-dwelling animals such as bilbies and bettongs. </p>
<p>And controlling foxes and feral cats, particularly in areas burned by large and severe fires, will likely increase mammal survival in post-fire environments. </p>
<p>Other <a href="https://doi.org/10.1126/science.abb0355">actions</a> will be needed to manage fire for mammal conservation. These include:</p>
<ul>
<li>habitat restoration</li>
<li>strategic planned burning</li>
<li>rapid recovery teams that assist wildlife after fire</li>
<li>reintroductions of threatened mammals</li>
<li>targeted fire suppression</li>
<li>reducing greenhouse gases.</li>
</ul>
<p>To explore whether these actions might be effective, <a href="https://link.springer.com/article/10.1007/s10980-020-01036-2">models</a> can simulate the impact of management strategies and fire regimes on species and ecosystems.</p>
<p>Finally, our research highlighted considerable uncertainty in the evidence for fire-related declines of many threatened mammals. Fires <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/geb.13520">influence</a> animal survival, reproduction and movement in many ways, and more research into threatened species ecology is needed to address Australia’s biodiversity crisis.</p>
<p><a href="https://bushfires2020.netlify.app"><img src="https://cdn.theconversation.com/static_files/files/1103/Explore.gif?1594552012" width="100%"></a></p><img src="https://counter.theconversation.com/content/185965/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Julianna Santos receives funding from the University of Melbourne, Holsworth Wildlife Research Endowment, Australian Wildlife Society University Research Grant, and Ecological Society of Australia Student Research Award.
This work was a collaboration among scientists from the University of Melbourne, University of New South Wales, New South Wales Department of Planning, Infrastructure and Environment, and Museums Victoria.</span></em></p><p class="fine-print"><em><span>Holly Sitters receives funding from the Australian Research Council and the Victorian Government. She is affiliated with the Australian Wildlife Conservancy and the Animal Justice Party. </span></em></p><p class="fine-print"><em><span>Luke Kelly receives funding from the Australian Research Council, Natural Hazards Research Australia and the Victorian Government.</span></em></p>The new paper also found some mammals are suffering due to a lack of fire.Julianna Santos, PhD candidate, The University of MelbourneHolly Sitters, Senior Ecologist, The University of MelbourneLuke Kelly, Senior Lecturer in Ecology, The University of MelbourneLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/644962016-09-27T16:07:18Z2016-09-27T16:07:18ZThe survival secrets of tiny mammals that could help them avoid extinction<figure><img src="https://images.theconversation.com/files/138476/original/image-20160920-16646-7m4m7f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Grey Mouse Lemurs enter torpor to conserve water.</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>We live in a changing world – and <a href="http://www.sciencedirect.com/science/article/pii/S2213305413000404">humans are the cause</a>. Habitat loss and fragmentation, pollution, the spread of invasive species, over-harvesting, pollution and climate change are just some of the problems. </p>
<p>It could be argued that the current changes to the Earth’s climate are part of a pattern that has gone on over aeons. <a href="http://www.indiana.edu/%7Egeol105/images/gaia_chapter_4/milankovitch.htm">Milankovitch’s cycles</a>, for example, describe how changes in the Earth’s movements, like the shape of its orbit around the sun or how much it is tilted on its axis, influence the climate. These changes occur at predictable intervals of 10 000 to 100 000 years. </p>
<p>But there is a growing consensus that the current rate and unpredictability of environmental change is <a href="http://science.sciencemag.org/content/299/5615/2005">unprecedented in Earth’s history</a>.</p>
<p>If humans are indeed driving the <a href="https://www.sciencedaily.com/releases/2015/06/150619152142.htm">sixth mass extinction</a>, what hope is there for hundreds of thousands of animal species? </p>
<p><a href="https://uanews.arizona.edu/story/ua-study-evolution-too-slow-to-keep-up-with-climate-change">A recent study</a> suggests that the majority of vertebrate species will not be able to evolve at a rate capable of withstanding current environmental change. This is because evolution is a slow process. It takes time for organisms to adapt.</p>
<p>As is already clear, some species are simply not going to be able to adapt. Extinction of species is something we have come to accept. And it’s not only the iconic species that are at risk. The <a href="https://www.uq.edu.au/news/article/2016/06/barrier-reef-rodent-first-mammal-declared-extinct-due-climate-change">first species to be declared extinct due to climate change</a> was a mouse, the Bramble Cay mosaic-tailed rat.</p>
<p>But some mammals might survive, or even thrive, for reasons that aren’t immediately obvious. It is worthwhile understanding what these are by <a href="http://www.journals.uchicago.edu/doi/abs/10.1086/686810">taking a different approach to how species are studied</a>. </p>
<h2>Thinking outside the box</h2>
<p>Animals have a range of adaptations that could help them cope. </p>
<p>Some species are able to migrate or shift their home ranges, evading unfavourable environments. For example, several rodent and shrew species in Yosemite National Park have shown <a href="http://science.sciencemag.org/content/322/5899/261">substantial range shifts</a>. This has been in response to global warming, but is clearly part of a pattern of behaviour that’s simply being applied to current circumstances.</p>
<p>Other coping mechanisms include mammals being able to secrete vasopressin, an antidiuretic hormone. This helps them to reabsorb water from the kidneys in the event of drought. <a href="http://br9xy4lf5w.scholar.serialssolutions.com/?sid=google&auinit=U&aulast=Shanas&atitle=Diet+salinity+and+vasopressin+as+reproduction+modulators+in+the+desert-dwelling+golden+spiny+mouse+%28Acomys+russatus%29&id=doi:10.1016/j.physbeh.2004.03.002&title=Physiology+%26+behavior&volume=81&issue=4&date=2004&spage=645&issn=0031-9384">Vasopressin</a> is released by the pituitary gland in response to water restriction. It stimulates contraction of the glomerular arterioles in the kidney, facilitating reabsorption of water in the collecting ducts. This could help with conserving water in the short-term. </p>
<p>Animals may also have <a href="http://rspb.royalsocietypublishing.org/content/205/1161/581">exaptations</a>, traits that evolved in response to past environments, that could be useful under changing conditions. An example is the <a href="http://link.springer.com/article/10.1007/s003600000140">eastern rock sengi, which enters torpor</a>, a state of inactivity like hibernation, in response to food restriction. Similarly, the <a href="http://link.springer.com/article/10.1007/s00114-009-0515-z">grey mouse lemur enters torpor</a>, but it does so to conserve water. So torpor didn’t evolve specifically for animals to cope with drought. But it could be useful if droughts increase.</p>
<p>The problem is that there isn’t a record of every morphological, physiological and behavioural trait of every single species. For example, some species, like the <a href="http://onlinelibrary.wiley.com/doi/10.1111/j.1439-0310.1971.tb01735.x/abstract">Spinifex hopping mouse</a>, are well studied, while others, such as the <a href="http://www.iucnredlist.org/details/22802/0">masked white-tailed</a> rat are so secretive that we know practically nothing about them.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/138438/original/image-20160920-11100-1fpad14.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/138438/original/image-20160920-11100-1fpad14.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/138438/original/image-20160920-11100-1fpad14.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/138438/original/image-20160920-11100-1fpad14.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/138438/original/image-20160920-11100-1fpad14.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/138438/original/image-20160920-11100-1fpad14.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/138438/original/image-20160920-11100-1fpad14.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/138438/original/image-20160920-11100-1fpad14.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The African striped mouse survived severe drought by forming non-kin huddling groups.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>Another coping strategy could be behavioural flexibility. Animals that are behaviourally flexible <a href="http://www.mdpi.com/2071-1050/5/1/163/htm">can change their behaviour quickly</a> in response to the environment. </p>
<p>A great example is the <a href="http://stripedmouse.com/">African striped mouse</a> from the Succulent Karoo of South Africa. During an <a href="http://jmammal.oxfordjournals.org/content/86/4/757.abstract">extreme drought in 2003</a>, 99% of mice died and the population faced extinction. Food was in short supply and many mice starved. Those that survived had no fat reserves. Being small-bodied, mice lose body heat quickly and, without fat, these mice were at extreme risk of freezing to death at night. </p>
<p>But they survived by forming <a href="http://www.nrcresearchpress.com/doi/abs/10.1139/z06-048#.V93Ya3oXdhA">non-kin huddling groups</a> that changed daily. This allowed them to conserve energy. Although striped mice are social, they normally nest in family groups. Nesting with strangers was a unique response to a stressful situation. </p>
<p>Strange as it may seem, the personality of animals may also affect their ability to adapt. Even within a species, some individuals are more likely to survive than others. For example, <a href="http://onlinelibrary.wiley.com/doi/10.1111/j.0030-1299.2008.16567.x/full">red squirrels</a> that are more active and risk-prone have a lower chance of survival. But we know little about which personalities will be better off during environmental change.</p>
<p><a href="http://www.journals.uchicago.edu/doi/10.1086/668204">Aggressive individuals</a> may be able to exploit or dominate limited, uniformly distributed resources, which would be great in simple environments like grasslands. But <a href="http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0091718">reactive individuals</a> are more behaviourally flexible, which could promote the discovery and exploitation of new resources. </p>
<p>In reality, it is nearly impossible to conserve species and reduce the rate of extinction if <a href="http://science.sciencemag.org/content/341/6145/504">we can’t predict</a> which species, and which individuals, will be threatened and which will survive. But <a href="http://www.journals.uchicago.edu/doi/abs/10.1086/686810">we can make a start</a> by identifying the stressors that are likely to have the most impact. This would include water availability during drought.</p>
<p>We could then identify traits that can promote survival. We should think outside the box and look for exaptations. It is important to take into account that animals can be flexible. In the end, it’s crucial to remember that populations are made up of individuals, which have different personalities, so some individuals will be better suited for coping than others. It’s important that top-down and bottom-up scientists make a point of talking to each other more.</p><img src="https://counter.theconversation.com/content/64496/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Tasmin Rymer is currently employed by James Cook University (JCU), Cairns, Australia, within the College of Science and Engineering. She is also a member of the Centre for Tropical Environmental and Sustainability Science (TESS) at JCU. She is also an honorary research fellow at the University of the Witwatersrand, Johannesburg, South Africa. </span></em></p>Climate change has an impact on small mammals and some battle to survive. But some others have developed intriguing coping mechanisms to survive.Tasmin Rymer, Lecturer College of Science & Engineering, Centre for Tropical Environmental and Sustainability Studies, James Cook UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/656632016-09-21T18:59:51Z2016-09-21T18:59:51ZYou can thank our pre-mammalian ancestors for your sexy teeth<figure><img src="https://images.theconversation.com/files/138412/original/image-20160920-11127-lx5rs3.jpg?ixlib=rb-1.1.0&rect=0%2C49%2C650%2C406&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">This skull belongs to the carnivorous gorgonopsian therapsid Smilesaurus ferox which lived 255 million years ago</span> <span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Smilesaurus_skull.jpg">Cradle of Humankind/Flickr/Wikimedia</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>Next time you’re getting ready for a hot date and pause to flash a toothy grin at yourself in the mirror, thank your ancestors.</p>
<p>Mammals have a dentition divided into three distinct types of teeth.</p>
<p>There are large, sharp canines and next to them incisors. Behind them, in our cheeks, are teeth known as post-canine dentition. This separation has been traced back more than 300 million years when our ancestors still looked like huge reptiles. </p>
<p>These were the pre-mammalian <a href="http://www.newworldencyclopedia.org/entry/Therapsid">therapsids</a>. They had long, sometimes sabre-like canines. Scientists long thought that these sharp teeth were deadly hunting devices. But there was a problem: even herbivorous species of therapsid had sabre-like canines. Their chompers clearly weren’t for hunting prey. Some speculated that the canines in question might be for defence from predators.</p>
<p>Or were they actually used for sexual display? </p>
<p>Today, sabre-tooth mammals such as the walrus or the deer-like <a href="http://www.iucnredlist.org/details/42190/0">muntiac</a>, have their canines constantly on display. This allows them to seduce mates or intimidate their kin. That’s the modern situation. My colleagues and I <a href="http://journals.plos.org/plosone/article?id=10.1371%2Fjournal.pone.0161457">wanted to know</a> whether sexual selection was also an important phenomenon among our pre-mammalian ancestors.</p>
<p>The answer, <a href="http://journals.plos.org/plosone/article?id=10.1371%2Fjournal.pone.0161457">uncovered</a> by cutting edge technology and careful study, is “yes”.</p>
<h2>Putting therapsids under the microscope</h2>
<p>Our research involved a team of palaeontologists from the University of the Witwatersrand’s <a href="https://www.wits.ac.za/esi/">Evolutionary Studies Unit</a>; a group from the university’s <a href="https://www.wits.ac.za/anatomicalsciences/">School of Anatomical Sciences</a> and scientists from the <a href="http://www.esrf.eu/">European Synchrotron Radiation Facility</a> in Grenoble, France.</p>
<p>Our subject was a mysterious fossil therapsid, Choerosaurus dejageri. It is part of the Eutheriodontia family. Little is known about this mammal-like reptile that lived 259 million years ago and belonged to the lineage that gave birth to mammals. Choerosaurus is unique, as it’s the only Eutheriodont to have two symmetrical bosses: horn-like structures on its upper and lower jaws, the maxilla and mandible.</p>
<p>We wanted to figure out what these cranial bosses were for: combat or sexual display.</p>
<p>Only one Choerosaurus fossil has been found, on a farm near Beaufort West in South Africa: a delicate skull. We used X-ray computerised micro-tomographic, or microCT, on this fossil. We compared the scans with those from another therapsid, the monstruous dinocephalian Moschops. The Moschops is known to have head butted its enemies, so its skull and cranial bosses were obviously developed for high energy combat. </p>
<p>But the Choereosaurus’ skull and cranial bosses were found to be too weak for such combat. In addition, the Choereosaurus’ maxillary boss was packed full of nerves and veins. This isn’t ideal for fighting, since any combat would cause a lot of pain and bleeding.</p>
<p>The maxillary boss is far more suited to supporting a colourful, sensitive cornified pad – a keratinous covering, like a horn. This suggests a bias towards display behaviour, and away from combat.</p>
<h2>Sexual selection</h2>
<p>This is the first evidence of structures dedicated solely to competition between males for mates and territory. These structures would have been used either for low energy fighting and/or sexual display in Eutheriodontia. Since this group was the direct ancestors of modern mammals, revealing their toothy secrets gives us a better understanding of our own mouths and those of other mammals.</p>
<p>The Choereosaurus fossil shows that sexual competition and the associated complex, ritualised behaviour like sexual display and ceremonies of intimidation were an important component of therapsid evolution. This finding suggests that sexual selection may have played a more important role in the origin of mammals than originally thought. </p>
<p>It’s a vital step to reshaping our understanding of humans’ deep evolutionary roots – right down to our canine teeth.</p><img src="https://counter.theconversation.com/content/65663/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Julien Benoit receives funding from PAST and its Scatterlings projects; the National Research Foundation of South Africa; and the DST-NRF Centre of Excellence in Palaeosciences (CoE in Palaeosciences). </span></em></p>Modern sabre-tooth mammals have their canines constantly on display. This allows them to seduce mates. But was sexual selection also an important phenomenon among our pre-mammalian ancestors?Julien Benoit, Postdoc in Vertebrate Palaeontology, University of the WitwatersrandLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/642542016-08-31T13:15:41Z2016-08-31T13:15:41ZGenetic studies may hold the key to saving west and central Africa’s lions<figure><img src="https://images.theconversation.com/files/135928/original/image-20160830-28244-1190wuj.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">African lions were all considered to belong to a single subspecies but new research refutes that.</span> <span class="attribution"><span class="source">Laura Bertola</span></span></figcaption></figure><p>Tropical rain forests, dry deserts and mountainous vistas: Africa is home to all of these very different ecosystems and more. Its varied ecosystems provide a habitat for numerous species, and the continent harbours a great richness of biodiversity.</p>
<p>But within species, there is another level of biodiversity: genetic variation. Even within species, there are wildly different populations. These are studied in the growing field of <a href="http://tolweb.org/treehouses/?treehouse_id=4383">phylogeography</a>. This science explores the distribution of genetic diversity, or the extent of different genetic lineages, in the context of geography. The formation of mountain ranges or islands, or the extension of rivers or forests, all influence the distribution of species: from trees, to tiny flying insects – to top predators like the lion. </p>
<p>Understanding species at this level is vitally important in the fight against extinction. Genetic diversity includes the evolutionary potential, referring to the genetic blue print that allows a species to adjust to a changing environment. If genetic diversity is lost, for example, when unique genetic lineages go extinct, it means that the species loses part of its adaptability. This makes species more vulnerable to extinction.</p>
<h2>New research paints a different picture of the lion</h2>
<p>Earlier <a href="http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0137975">research</a> has shown that lions in west and central Africa deviate from their counterparts in east and southern Africa. This, despite the fact that all African lions are considered to belong to a single subspecies. </p>
<p>In a new <a href="http://www.nature.com/articles/srep30807">publication</a>, a new magnitude of data was gathered analysing lion populations from 22 countries. This data set includes samples from each confirmed lion population in west and central Africa. This region is particularly important because lions and other wildlife are declining. As a result, it is a major concern for conservation <a href="http://news.nationalgeographic.com/news/2014/01/140108-west-african-lions-endangered-conservation-science/">projects</a>.</p>
<p>The data helped discern six lineages in the lion. These can be divided into two major groups:</p>
<ol>
<li><p>A northern group, containing lions from west Africa, central Africa and the Asiatic subspecies.</p></li>
<li><p>A southern group, containing lions from north east Africa, east/southern Africa and south west Africa. </p></li>
</ol>
<p>Based on genetic data it was also possible to calculate the timing of this split, based on the notion that differences in the DNA accumulate over time. It was estimated that the major split may have occurred around 300,000 years ago. This estimate allows us to explore further what happened during this period which could explain the differentiation between these two groups of lions.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/135777/original/image-20160829-17862-e7tvnh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/135777/original/image-20160829-17862-e7tvnh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/135777/original/image-20160829-17862-e7tvnh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/135777/original/image-20160829-17862-e7tvnh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/135777/original/image-20160829-17862-e7tvnh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/135777/original/image-20160829-17862-e7tvnh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/135777/original/image-20160829-17862-e7tvnh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/135777/original/image-20160829-17862-e7tvnh.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">New research shows the differentiation in lion genetics came about from the expansion of African rain forests around 300,000 years ago.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>Reasons for differentiation</h2>
<p>The researchers suggest that during this period the African rain forest expanded and probably formed a barrier for lion dispersal. Cyclical expansion of rain forest on one side and dry desert on the other side may have pushed lion populations into isolated pockets of suitable habitat. And this led to the genetic differentiation we still see today. </p>
<p>Another <a href="https://www.researchgate.net/publication/235635309_Climate_envelope_models_suggest_spatio-temporal_co-occurrence_of_refugia_of_African_birds_and_mammals">study</a>, which used habitat suitability models for mammal and bird species, predicted six regions that maintained a suitable habitat during historic periods of climate change. These six regions correspond directly with the six genetic lineages found in the lion. This suggests that the high resolution phylogeographic pattern found in the lion is illustrative for a range of species. </p>
<p>Since these climatic changes didn’t just act on the lion. A large variety of species like giraffe, buffalo, cheetah and spotted hyena were also affected. The recent publication used the case of the lion to compare it to available data sets of other Savannah mammals. It showed that a large number of species have a similar pattern in which populations from west and central Africa deviated from populations in east and southern Africa. </p>
<p>This is an important finding because it shows that we will lose important and unique biodiversity if we fail to preserve the populations in this region.</p>
<h2>Challenging times</h2>
<p>In July a delegation of the west and central African lion conservation network, <a href="http://www.rocal-lion.org/">ROCAL</a>, travelled to Botswana to explore opportunities for <a href="http://leofoundation.org/en/study-trip-to-botswana/">collaboration</a>. There are large differences between parts of west/central Africa and parts of east/southern Africa in terms of ecology, politics and their socioeconomic situations. These differences present many challenges. But they are also a source of opportunities for west and central African countries to market their unique situation, both in terms of natural and cultural diversity.</p>
<p>In addition, during the <a href="http://www.iucnworldconservationcongress.org/">IUCN World Conservation Congress</a> in September 2016, a delegation of researchers who were also involved in the publication will propose to set up a Species Action Partnership for west and central Africa. The hope is that this will facilitate coordination and funding of projects in the region.</p>
<p>Phylogeographic data sets show why it’s necessary to move beyond the idea merely of preserving a species. Genetic data can be used to develop a conservation plan that incorporates the full scope of biodiversity. Failure to do so could see the African continent lose a unique part of its richness in the next few decades.</p><img src="https://counter.theconversation.com/content/64254/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Laura Bertola 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>African lions were initially thought to belong to a single subspecies but new research shows that there is more diversity on the African continent.Laura Bertola, Researcher in Conservation Genetics, Phylogeny/Phylogeography, Population Genetics/Genomics and Environmental DNA, Leiden UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/588192016-05-08T15:05:24Z2016-05-08T15:05:24ZCounting cheetahs: a new approach yields results in the Maasai Mara<figure><img src="https://images.theconversation.com/files/121596/original/image-20160507-32047-1eullie.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A new method of counting cheetahs has helped researchers to get a better idea of their numbers.
</span> <span class="attribution"><span class="source">Mara Cheetah Project, Femke Broekhuis</span></span></figcaption></figure><p>Being a cheetah researcher in Kenya’s Maasai Mara, I’m often asked how many cheetahs there are in the region. It’s an important question, especially for conservation as it is crucial to accurately estimate population sizes and to monitor trends into the future. </p>
<p>In the early 1900s it was believed that around 100,000 cheetahs roamed the earth. The most recent estimate by the International Union for Conservation of Nature puts the figure at <a href="http://www.iucnredlist.org/details/219/0">6,600</a> – mainly in eastern and southern Africa – amid fears that the fastest land mammal is racing to extinction. Cheetahs are now extinct in 20 countries and occupy only 17% of their historic range. The remaining populations that are of global importance are found in southern Africa – Botswana, Namibia and South Africa - and in East Africa – Kenya and Tanzania. Of all of these locations least is known about cheetahs in Kenya. </p>
<p>We set out to address this gap by designing and conducting an intensive field survey based on search-encounters of cheetahs in the <a href="http://dx.doi.org/10.1371/journal.pone.0153875.g001">Maasai Mara National Reserve and its surrounding conservancies</a>. Accurate estimations are important, especially when trying to determine whether a population is stable, increasing or decreasing.</p>
<p>But deriving an answer is more difficult than it might seem. The population size of any species is obviously affected by a number of factors including births and deaths and the fact that individuals move in and out of an area. </p>
<p>In the case of cheetahs, there are further complications. It is unrealistic to assume that every individual will be sighted during a survey. They are generally not easy to find partly because of their extensive ranging behaviour. In Serengeti National Park, Tanzania, home-ranges for both semi-nomadic females and males are around 800 km2 and in Namibia they are on average 1647 km2.</p>
<h2>The process of counting</h2>
<p>Our research covered about 2400 km², an area half the size of the Great Salt Lake in the US. The data for this <a href="http://dx.plos.org/10.1371/journal.pone.0153875">study</a> were collected during a three month period. The time period was to minimise the impact of birth or deaths and immigration or emigration. Over the three months a team of five field vehicles drove 8400 km, roughly the distance from South Africa’s Cape Town to Gibraltar off the coast of Spain, in search of cheetahs.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/121595/original/image-20160507-32037-9r940g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/121595/original/image-20160507-32037-9r940g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/121595/original/image-20160507-32037-9r940g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=475&fit=crop&dpr=1 600w, https://images.theconversation.com/files/121595/original/image-20160507-32037-9r940g.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=475&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/121595/original/image-20160507-32037-9r940g.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=475&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/121595/original/image-20160507-32037-9r940g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=597&fit=crop&dpr=1 754w, https://images.theconversation.com/files/121595/original/image-20160507-32037-9r940g.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=597&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/121595/original/image-20160507-32037-9r940g.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=597&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 Maasai Mara is one of the few remaining strongholds for the global cheetah population.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>Once cheetahs were found, the necessary information, including the identity of the cheetah – determined by its unique spot pattern – was recorded. These data were then analysed using an advanced Bayesian Spatially Explicit Capture Recapture model. This statistical model incorporates information on when and where a cheetah was sighted and when and where the cheetah was subsequently resighted during the survey period.</p>
<p>The method is more robust than those used previously because: </p>
<ol>
<li><p>The spatially explicit method used can distinguish visiting animals from those that reside permanently within the surveyed area, avoiding potential overestimation of numbers. This can be compared to counting the population of Manhattan in the daytime, which would give a vastly inflated figure because of the influx of commuters from neighbouring areas.</p></li>
<li><p>It accounts for the probability that cheetahs are seen, thereby addressing the potential problem that not every single individual in a population is likely to be seen which would underestimate the numbers.</p></li>
<li><p>It does not conclude results in the way that is often done in surveys based on, for example, animal tracks.</p></li>
</ol>
<h2>What the results showed</h2>
<p>The results showed a density of 1.28 adult cheetahs per 100km2. This is lower than previous figures published and estimates based on so-called expert opinion. This may be because the tools are now available to accurately estimate numbers. This number seems low, but it is higher than estimates currently available for other areas in Africa. In <a href="http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0115136">Algeria</a> there are an estimated 0.02 to 0.05 per 100km² and in <a href="http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0142508">Botswana</a> 0.61 ± 0.18 cheetahs per 100km².</p>
<p>But this does not mean that cheetahs in the Maasai Mara are not threatened. Cheetahs face a kaleidoscope of threats. These include habitat loss, prey depletion and human-wildlife conflict. With the results from our current study we will now be able to determine the impact these threats have on cheetahs. </p>
<p>The Maasai Mara is one of the few remaining strongholds for the global cheetah population. This study provides the data needed to quantify and monitor threats and conservation efforts going into the future. The analysis, which was spatially-explicit, revealed hotspots of cheetah activity. The next step is to determine how the distribution of these high-density areas is correlated with environmental variables like habitat, prey, predators, or human factors including livestock grazing.</p>
<p>But the relevance of the study goes beyond cheetahs in the Maasai Mara. These measures also provide important information about big cat ecology that can aid conservation. For example, India has been considering the <a href="https://en.wikipedia.org/wiki/Cheetah_reintroduction_in_India">reintroduction of the African cheetah</a>. Even in a prey-rich area like the Maasai Mara, the density of cheetahs is low. This suggests that the resource requirements for these cats are perhaps much larger than would currently be available in the Indian subcontinent. In addition, the method can be applied to other areas and other charismatic species like lions. Researchers are therefore encouraged, where possible, to move away from numbers based on expert opinion and estimate populations using more robust survey methods.</p><img src="https://counter.theconversation.com/content/58819/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Femke Broekhuis is the Project Director of the Kenya Wildlife Trust's Mara Cheetah Project. The Mara Cheetah Project receives funding from the BAND Foundation, VIDDA Foundation, Wildscapes Foundation,Base Camp Foundation, African Wildlife Fund, Asilia and various private donors who have donated through the Kenya Wildlife Trust. Femke Broekhuis is affiliated with the Wildlife Conservation Research Unit (WildCRU), University of Oxford.</span></em></p>Accurately counting cheetah numbers is crucial to ensuring the survival of the species.Femke Broekhuis, Researcher, Project Director Mara Cheetah Project, University of OxfordLicensed as Creative Commons – attribution, no derivatives.