tag:theconversation.com,2011:/us/topics/human-impacts-55133/articlesHuman impacts – The Conversation2022-04-18T12:27:48Ztag:theconversation.com,2011:article/1791752022-04-18T12:27:48Z2022-04-18T12:27:48ZIs it possible to heal the damage we have already done to the Earth?<figure><img src="https://images.theconversation.com/files/458325/original/file-20220415-26-n2wfxj.jpeg?ixlib=rb-1.1.0&rect=4%2C1%2C1034%2C830&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The Earth viewed from the Apollo 8 lunar mission on Dec. 24, 1968. </span> <span class="attribution"><a class="source" href="https://www.nasa.gov/multimedia/imagegallery/image_feature_1249.html">NASA</a></span></figcaption></figure><figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=293&fit=crop&dpr=1 600w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=293&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=293&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=368&fit=crop&dpr=1 754w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=368&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=368&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<p><em><a href="https://theconversation.com/us/topics/curious-kids-us-74795">Curious Kids</a> is a series for children of all ages. If you have a question you’d like an expert to answer, send it to <a href="mailto:curiouskidsus@theconversation.com">curiouskidsus@theconversation.com</a>.</em></p>
<hr>
<blockquote>
<p><strong>Is it possible to heal the damage we have already done to the Earth? – Anthony, age 13</strong> </p>
</blockquote>
<hr>
<p>Sometimes it may seem that humans have altered the Earth beyond repair. But our planet is an incredible system in which energy, water, carbon and so much else flows and nurtures life. It is <a href="https://www.nationalgeographic.org/topics/resource-library-age-earth/?q=&page=1&per_page=25">about 4.5 billion years old</a> and has been through enormous changes.</p>
<p>At some points in Earth’s history, <a href="https://www.earthmagazine.org/article/flammable-planet-fire-finds-its-place-earth-history">fires burned over large areas</a>. At others, much of it was <a href="https://www.climate.gov/news-features/climate-qa/whats-coldest-earths-ever-been">covered with ice</a>. There also have been <a href="https://www.amnh.org/shelf-life/six-extinctions">mass extinctions</a> that wiped out nearly every living thing on its surface. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/I4EZCy14te0?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Earth’s climate has varied from extremely warm periods with no polar ice caps to phases when much of the planet was frozen.</span></figcaption>
</figure>
<p>Our living planet is incredibly resilient and can heal itself over time. The problem is that its self-healing systems are very, very slow. The Earth will be fine, but humans’ problems are more immediate. </p>
<p>People have <a href="https://www.scientificamerican.com/article/length-of-human-domination/">damaged the systems that sustain us</a> in many ways. We have polluted <a href="https://www.who.int/health-topics/air-pollution#tab=tab_1">air</a> and <a href="https://www.unep.org/explore-topics/water/what-we-do/tackling-global-water-pollution">water</a>, strewn <a href="https://www.oecd.org/environment/plastic-pollution-is-growing-relentlessly-as-waste-management-and-recycling-fall-short.htm">plastic</a> and <a href="https://www.unep.org/explore-topics/resource-efficiency/what-we-do/cities/solid-waste-management">other trash</a> on land and in oceans and rivers, and <a href="https://www.nytimes.com/interactive/2022/03/03/climate/biodiversity-map.html">destroyed habitats</a> for plants and animals. </p>
<p>But we know how to <a href="https://theconversation.com/tropical-forests-can-recover-surprisingly-quickly-on-deforested-lands-and-letting-them-regrow-naturally-is-an-effective-and-low-cost-way-to-slow-climate-change-173302">help natural processes</a> clean up many of these messes. And there has been <a href="https://gispub.epa.gov/air/trendsreport/2020/#home">a lot of progress</a> since people <a href="https://www.earthday.org/history/">started waking up to these problems 50 years ago</a>. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/458327/original/file-20220415-14135-dks4a6.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Graph showing economic trends since 1970 and decline in six major air pollutants." src="https://images.theconversation.com/files/458327/original/file-20220415-14135-dks4a6.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/458327/original/file-20220415-14135-dks4a6.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/458327/original/file-20220415-14135-dks4a6.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/458327/original/file-20220415-14135-dks4a6.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/458327/original/file-20220415-14135-dks4a6.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/458327/original/file-20220415-14135-dks4a6.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/458327/original/file-20220415-14135-dks4a6.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Since 1970, the U.S. has greatly reduced air pollution even as its economy has grown dramatically.</span>
<span class="attribution"><a class="source" href="https://www.epa.gov/sites/default/files/2021-05/epa-banner-images/2020_baby_graphic_1970-2020.png">USEPA</a></span>
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<p>There still are problems to solve. Some pollutants, like plastic, <a href="https://www.nationalgeographic.com/environment/article/plastic-pollution">last for thousands of years</a>, so it’s much better to stop releasing them than to try to collect them later. And <a href="https://ourworldindata.org/extinctions">extinction</a> is permanent, so the only effective way to reduce it is to be more careful about protecting animals, plants and other species. </p>
<h2>Reversing climate change</h2>
<p>The most serious damage humans are doing to the Earth comes mainly from burning coal, oil and gas, which is <a href="https://theconversation.com/ipcc-climate-report-profound-changes-are-underway-in-earths-oceans-and-ice-a-lead-author-explains-what-the-warnings-mean-165588">dramatically warming its climate</a>. Burning these carbon-based fuels is changing the fundamental chemistry and physics of the air and oceans. </p>
<p>Every lump of coal or gallon of gasoline that’s burned releases carbon dioxide into the atmosphere. There it <a href="https://climatekids.nasa.gov/climate-change-meaning/">heats the Earth’s surface</a>, causing floods, fires and droughts. Some of this added carbon dioxide dissolves into the oceans and <a href="https://www.noaa.gov/education/resource-collections/ocean-coasts/ocean-acidification">makes them more acidic</a>, which threatens ocean food webs. </p>
<p>Climate change is a problem that will get worse until humans stop making it worse – and then it will take many centuries for the climate to return to what it was like <a href="https://theconversation.com/what-is-a-pre-industrial-climate-and-why-does-it-matter-78601">before the Industrial Revolution</a>, when human actions started altering it on a large scale. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1514684277660663816"}"></div></p>
<p>The only way to avoid making things worse is to stop setting carbon on fire. That means societies need to work hard to build an energy system that can help everyone live well without the need to burn carbon.</p>
<p>The good news is that we know how to make energy without releasing carbon dioxide and other pollution. Electricity made from solar, wind and geothermal power is now <a href="https://www.weforum.org/agenda/2021/07/renewables-cheapest-energy-source">the cheapest energy in history</a>. Cleaning up the global electricity supply and then <a href="https://www.vox.com/2016/9/19/12938086/electrify-everything">electrifying everything</a> can very quickly stop carbon pollution from getting worse. </p>
<p>This will require electric cars and trains, electric heating and cooking, and electric factories. We’ll also need new kinds of transmission and storage systems to get all that clean electricity from where it’s made to where it’s used. </p>
<p>The rest of the carbon mess can be cleaned up through <a href="https://www.nationalgeographic.com/science/article/partner-content-solution-to-climate-change-below-our-feet">better farm and forest management</a> that stores carbon in land and plants instead of releasing it into the atmosphere. This is also a problem that scientists know how to solve.</p>
<p>The Earth will certainly heal, but it may take a very long time. The best way to start is with everyone doing their part to avoid making the damage any worse. </p>
<hr>
<p><em>Hello, curious kids! Do you have a question you’d like an expert to answer? Ask an adult to send your question to <a href="mailto:curiouskidsus@theconversation.com">CuriousKidsUS@theconversation.com</a>. Please tell us your name, age and the city where you live.</em></p>
<p><em>And since curiosity has no age limit – adults, let us know what you’re wondering, too. We won’t be able to answer every question, but we will do our best.</em></p><img src="https://counter.theconversation.com/content/179175/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Scott Denning has previously receives funding from the US National Science Foundation, the National Aeronautic and Space Administration, the Department of Energy, and the National Oceanic and Atmospheric Administration . </span></em></p>The Earth is a resilient planet, but people are altering it in ways that may take centuries to reverse.Scott Denning, Professor of Atmospheric Science, Colorado State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1764452022-02-06T19:06:56Z2022-02-06T19:06:56ZJust 16% of the world’s coastlines are in good shape – and many are so bad they can never fully recover<figure><img src="https://images.theconversation.com/files/444463/original/file-20220204-25-1luokrn.png?ixlib=rb-1.1.0&rect=5%2C0%2C1911%2C1074&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Leonardo Felippi</span></span></figcaption></figure><p>Only about 16% of the world’s coastal regions are in relatively good condition, according to our <a href="https://doi.org/10.1111/cobi.13874">world-first research released today</a>, and many are so degraded they can’t be restored to their original state.</p>
<p>Places where the land meets the sea are crucial for our planet to function. They support biodiversity and the livelihoods of billions of people. But to date, understanding of the overall state of Earth’s coastal regions has been poor. </p>
<p>Our research, involving an international team of experts, revealed an alarming story. Humanity is putting heavy pressure on almost half the world’s coastal regions, including a large proportion of protected areas. </p>
<p>All nations must ramp up efforts to preserve and restore their coastal regions – and the time to start is right now.</p>
<figure class="align-center ">
<img alt="Fishermen bring their catch ashore a polluted bank" src="https://images.theconversation.com/files/444493/original/file-20220204-21-1qsjehr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/444493/original/file-20220204-21-1qsjehr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/444493/original/file-20220204-21-1qsjehr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/444493/original/file-20220204-21-1qsjehr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/444493/original/file-20220204-21-1qsjehr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/444493/original/file-20220204-21-1qsjehr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/444493/original/file-20220204-21-1qsjehr.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">Coastlines support the livelihoods of billions of people.</span>
<span class="attribution"><span class="source">ROLEX DELA PENA/EPA</span></span>
</figcaption>
</figure>
<h2>Our coasts are vital – and vulnerable</h2>
<p>Coastal regions encompass some of the most diverse and unique ecosystems on Earth. They include coral reefs, kelp forests, seagrass, tidal flats, mangroves, estuaries, salt marshes, wetlands and coastal wooded habitat. </p>
<p>Many animal species, including those that migrate, rely on coastlines for breeding, foraging and protection. Coastal sites are also where rivers discharge, mangrove forests exchange nutrients with the ocean, and tidal flows are maintained.</p>
<p>Humans also need coastlines. Among other functions, they support our fisheries, protect us from storms and, importantly, store carbon to help mitigate climate change.</p>
<p>As much as 74% of the world’s population <a href="https://www.jstor.org/stable/4299200">live within</a> 50 kilometres of the coast, and humans put pressure on coastal environments in myriad ways.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/wetlands-have-saved-australia-27-billion-in-storm-damage-over-the-past-five-decades-153638">Wetlands have saved Australia $27 billion in storm damage over the past five decades</a>
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</em>
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<p>In marine environments, these pressures include:</p>
<ul>
<li>fishing at various intensities</li>
<li>land-based nutrient, organic chemical and light pollution</li>
<li>direct human impacts such as via recreation</li>
<li>ocean shipping</li>
<li>climate change (and associated ocean acidification, sea-level rise and increased sea surface temperatures).</li>
</ul>
<p>On land, human pressures on our coastlines include:</p>
<ul>
<li>built environments, such as coastal developments </li>
<li>disturbance </li>
<li>electricity and transport infrastructure</li>
<li>cropping and pasture lands, which clears ecosystems and causes chemical and nutrient runoff into waterways.</li>
</ul>
<p>To date, assessments of the world’s coastal regions have largely focused solely on either the land or ocean, rather than considering both realms together. Our research sought to address this.</p>
<figure class="align-center ">
<img alt="cargo ship and dock workers at port" src="https://images.theconversation.com/files/444494/original/file-20220204-17-1eqkxp8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/444494/original/file-20220204-17-1eqkxp8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=395&fit=crop&dpr=1 600w, https://images.theconversation.com/files/444494/original/file-20220204-17-1eqkxp8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=395&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/444494/original/file-20220204-17-1eqkxp8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=395&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/444494/original/file-20220204-17-1eqkxp8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=496&fit=crop&dpr=1 754w, https://images.theconversation.com/files/444494/original/file-20220204-17-1eqkxp8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=496&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/444494/original/file-20220204-17-1eqkxp8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=496&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Shipping is among the human activities putting pressure on coastlines.</span>
<span class="attribution"><span class="source">Chad Hipolito/ AP</span></span>
</figcaption>
</figure>
<h2>A troubling picture</h2>
<p>We integrated existing human impact maps for both <a href="https://doi.org/10.1016/j.oneear.2020.08.009">land</a> and <a href="https://doi.org/10.1038/s41598-019-47201-9">ocean</a> areas. This enabled us to assess the spectrum of human pressure across Earth’s coastal regions to identify those that are highly degraded and those intact. </p>
<p>Both maps use data up to the year 2013 – the most recent year for which cohesive data is available. </p>
<p>No coastal region was free from human influence. However, 15.5% of Earth’s coastal regions remained intact – in other words, humans had exerted only low pressure. Many of the intact coastal regions were in Canada, followed by Russia and Greenland. </p>
<p>Large expanses of intact coast were also found elsewhere including Australia, Indonesia, Papua New Guinea, Chile, Brazil and the United States. </p>
<p>Troublingly, 47.9% of coastal regions have been exposed to very high levels of human pressure. And for 84% of countries, more than half their coastal regions were degraded. </p>
<p>What’s more, human pressures were high in about 43% of protected coastal regions – those regions purportedly managed to conserve nature.</p>
<p>Coastal regions containing sea grasses, savannah and coral reefs had the highest levels of human pressure compared to other coastal ecosystems. Some coastal regions may be so degraded they cannot be restored. Coastal ecosystems are highly complex and once lost, it is likely impossible to restore them to their original state. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/5-major-heatwaves-in-30-years-have-turned-the-great-barrier-reef-into-a-bleached-checkerboard-170719">5 major heatwaves in 30 years have turned the Great Barrier Reef into a bleached checkerboard</a>
</strong>
</em>
</p>
<hr>
<figure class="align-center ">
<img alt="coral reef and boat" src="https://images.theconversation.com/files/444499/original/file-20220204-23-jqk017.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/444499/original/file-20220204-23-jqk017.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/444499/original/file-20220204-23-jqk017.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/444499/original/file-20220204-23-jqk017.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/444499/original/file-20220204-23-jqk017.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/444499/original/file-20220204-23-jqk017.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/444499/original/file-20220204-23-jqk017.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Coastal regions containing coral are among the world’s most degraded by human activity.</span>
<span class="attribution"><span class="source">AP</span></span>
</figcaption>
</figure>
<h2>So where to now?</h2>
<p>It’s safe to say intact coastal regions are now rare. We urge governments to urgently conserve the coastal regions that remain in good condition, while restoring those that are degraded but can still be fixed.</p>
<p>To assist with this global task, we have made our dataset publicly available and free to use <a href="https://doi.org/10.48610/fd85061">here</a>.</p>
<p>Of course, the right conservation and restoration actions will vary from place to place. The actions might include, but are not limited to:</p>
<ul>
<li><p>improving environmental governance and laws related to encroaching development</p></li>
<li><p>increasing well-resourced protected areas</p></li>
<li><p>mitigating land-use change to prevent increased pollution run-off</p></li>
<li><p>better community and local engagement</p></li>
<li><p>strengthening Indigenous involvement in managing coastal regions</p></li>
<li><p>effective management of fishing resources</p></li>
<li><p>addressing climate change</p></li>
<li><p>tackling geopolitical and socioeconomic drivers of damage to coastal environments.</p></li>
</ul>
<p>In addition, there’s an urgent need for national and global policies and programs to effectively managing areas where the land and ocean converge. </p>
<p>Humanity’s impact on Earth’s coastal regions is already severe and widespread. Without urgent change, the implications for both coastal biodiversity and society will become even more profound.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-traditional-owners-and-officials-came-together-to-protect-a-stunning-stretch-of-wa-coast-163078">How Traditional Owners and officials came together to protect a stunning stretch of WA coast</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/176445/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Brooke Williams receives funding from an Australian Government Research Training Program Scholarship. </span></em></p><p class="fine-print"><em><span>James Watson has received funding from the Australian Research Council and National Environmental Science Program. He serves on scientific committees for Bush Heritage Australia and BirdLife Australia.</span></em></p><p class="fine-print"><em><span>Amelia Wenger 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>All nations must ramp up efforts to preserve and restore their coastal regions – and the time to start is right now.Brooke Williams, Postdoctoral research fellow, The University of QueenslandAmelia Wenger, Research fellow, The University of QueenslandJames Watson, Professor, The University of QueenslandLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1526192021-02-01T22:36:04Z2021-02-01T22:36:04ZHumans force wild animals into tight spots, or send them far from home. We calculated just how big the impact is<figure><img src="https://images.theconversation.com/files/377725/original/file-20210108-15-lqa85.jpg?ixlib=rb-1.1.0&rect=0%2C302%2C2556%2C1521&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://flic.kr/p/nnXwcc">Eric Fortin/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span></figcaption></figure><p>The COVID pandemic has shown us that disruptions to the way we move around, complete daily activities and interact with each other can shatter our wellbeing. </p>
<p>This doesn’t apply only to humans. Wildlife across the globe find themselves in this situation every day, irrespective of a global pandemic.</p>
<p>Our latest research published today in <a href="https://www.nature.com/articles/s41559-020-01380-1">Nature Ecology and Evolution</a> has, for the first time, quantified the repercussions of logging, pollution, hunting, and other human disturbances, on the movements of a wide range of animal species. </p>
<p>Our findings were eye-opening. We found human disturbances, on average, restricted an animal’s movements by 37%, or increased it by 70%. That’s like needing to travel an extra 11 km to get to work each day (<a href="https://www.abs.gov.au/ausstats/abs@.nsf/Lookup/by%20Subject/2071.0.55.001%7E2016%7EMain%20Features%7ECommuting%20Distance%20for%20Australia%7E1#:%7E:text=The%20capital%20cities%20with%20the,average%20commutes%20with%2011.7%20km.">Australia’s average is 16 km</a>).</p>
<h2>Disruptions cascade through the ecosystem</h2>
<p>The ability to travel is essential to animal survival because it allows animals to find mates, food and shelter, escape predators and competitors, and avoid disturbances and threats. </p>
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Read more:
<a href="https://theconversation.com/its-not-too-late-to-save-them-5-ways-to-improve-the-governments-plan-to-protect-threatened-wildlife-147669">It's not too late to save them: 5 ways to improve the government's plan to protect threatened wildlife</a>
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<p>And because animal movement is linked to many important ecological processes — such as pollination, seed dispersal and soil turnover — disruptions to movement can cascade through ecosystems. </p>
<p>Our study involved analysing published data on changes in animal movement in response to different types of disturbance or habitat modification by humans. This included agriculture, logging, grazing, recreation, hunting, and pollution, amongst others.</p>
<p>All up, we looked at 719 records of animal movement, spanning 208 studies and 167 species of birds, mammals, reptiles, fish, insects and amphibians. The size of the species we studied ranged from the sleepy orange butterfly to the white shark.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/377726/original/file-20210108-21-1nsidwh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/377726/original/file-20210108-21-1nsidwh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=398&fit=crop&dpr=1 600w, https://images.theconversation.com/files/377726/original/file-20210108-21-1nsidwh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=398&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/377726/original/file-20210108-21-1nsidwh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=398&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/377726/original/file-20210108-21-1nsidwh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=500&fit=crop&dpr=1 754w, https://images.theconversation.com/files/377726/original/file-20210108-21-1nsidwh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=500&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/377726/original/file-20210108-21-1nsidwh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=500&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Species included in our study, clockwise from top-left: sleepy orange butterfly, southern leopard frog, tawny owl, white shark, diademed sifaka and red-eared slider turtle.</span>
<span class="attribution"><span class="source">Photos adapted from Flickr under Creative Commons license CC BY 2.0. Clockwise from top-left: Anne Toal; Trish Hartmann; Les Pickstock; Elias Levy; John Crane; USFWS Midwest Region.</span></span>
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<h2>What we found</h2>
<p>We found changes in movement are very common, with two-thirds of the 719 cases comprising an increase or decrease in movement of 20% or more. More than one-third of cases changed by 50% or more.</p>
<p>Whether an animal increases or decreases its movement in response to disturbance from humans depends on the situation. </p>
<p>Animals may run away from humans, or move further in search of food and nesting sites. For example, a 2020 study on <a href="https://zslpublications.onlinelibrary.wiley.com/doi/abs/10.1111/acv.12596">koalas</a> found their movements were longer and more directed in areas where habitats weren’t well connected, because they had to travel further to reach food patches. </p>
<p>Likewise, the daily movement distances of <a href="https://academic.oup.com/jmammal/article/100/1/158/5238784?login=true">mountain brushtail possums</a> in central Victoria were 57% higher in remnant bushland along roadsides, compared to large forest areas.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/377681/original/file-20210107-13-rr3g71.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/377681/original/file-20210107-13-rr3g71.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/377681/original/file-20210107-13-rr3g71.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/377681/original/file-20210107-13-rr3g71.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/377681/original/file-20210107-13-rr3g71.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/377681/original/file-20210107-13-rr3g71.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/377681/original/file-20210107-13-rr3g71.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/377681/original/file-20210107-13-rr3g71.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">Land clearing can cause animals to move through risky areas in search of suitable habitat.</span>
<span class="attribution"><a class="source" href="https://link.springer.com/article/10.1007/s10980-019-00795-x">Tim Doherty</a>, <span class="license">Author provided</span></span>
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<p>Decreases in movement can occur where animals encounter barriers (such as highways), if they need to shelter from a disturbance, or can’t move as efficiently through altered habitats. In the United States, for example, <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/ele.13344">researchers played</a> a recording of humans talking and found it caused a 34% decrease in the speed that mountain lions move.</p>
<p>On the other hand, some decreases in movement occur where an animal actually benefits from habitat changes. A wide range of animals — including storks, vultures, crows, foxes, mongooses, hyenas and monitor lizards — have <a href="https://www.sciencedirect.com/science/article/pii/S2351989417301257">shorter movements around garbage dumps</a> because they don’t have to move very far to get the food they need.</p>
<h2>Huge changes in movement make animals vulnerable</h2>
<p>Overall, we found the average increase in animal movement was +70% and the average decrease was -37%, which are substantial changes. </p>
<p>Imagine having to increase the distance you travel to work, the shops and to see family and friends, by 70%. You would spend a lot more time and energy travelling and have less time to rest or do fun things. And if you live in Melbourne, you know what substantial reductions in movement are like due to COVID-related lockdowns.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/378723/original/file-20210114-19-1g4xo43.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/378723/original/file-20210114-19-1g4xo43.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=415&fit=crop&dpr=1 600w, https://images.theconversation.com/files/378723/original/file-20210114-19-1g4xo43.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=415&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/378723/original/file-20210114-19-1g4xo43.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=415&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/378723/original/file-20210114-19-1g4xo43.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=521&fit=crop&dpr=1 754w, https://images.theconversation.com/files/378723/original/file-20210114-19-1g4xo43.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=521&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/378723/original/file-20210114-19-1g4xo43.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=521&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Examples of what a 70% increase (bottom left) and a 37% decrease (bottom right) in your normal home range (top) might look life if you lived in Melbourne.</span>
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<p>In addition to greater energy expenditure, increased movements can mean animals need to move through risky areas where they are more vulnerable to predation.</p>
<p>And decreases in movement can be harmful if animals can’t find adequate food or disperse to find mates, or if ecological processes such as seed dispersal are disrupted. </p>
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Read more:
<a href="https://theconversation.com/predators-prey-and-moonlight-singing-how-phases-of-the-moon-affect-native-wildlife-140556">Predators, prey and moonlight singing: how phases of the Moon affect native wildlife</a>
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<p>For example, <a href="https://royalsocietypublishing.org/doi/10.1098/rsos.190397">flightless rails</a>, birds native to New Zealand, are important for dispersing seeds. But research showed birds in areas of high human activity (campgrounds) moved 35–41% shorter distances than birds away from campgrounds. This could limit the population growth of plants if their seeds are not being dispersed as far.</p>
<h2>When disturbances are unpredictable</h2>
<p>We compared the effects of different disturbance types on animals by splitting them into two categories: human activities (such as hunting, military procedures and recreation like tourism) and habitat modification (such as agriculture and logging).</p>
<p>Both disturbance types can have severe impacts, ranging from a 90% decrease to 1,800% increase in movement for human activities, and a 97% decrease to a 3,300% increase for habitat modifications.</p>
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<img alt="" src="https://images.theconversation.com/files/377532/original/file-20210107-22-tnnrm0.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/377532/original/file-20210107-22-tnnrm0.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=392&fit=crop&dpr=1 600w, https://images.theconversation.com/files/377532/original/file-20210107-22-tnnrm0.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=392&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/377532/original/file-20210107-22-tnnrm0.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=392&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/377532/original/file-20210107-22-tnnrm0.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=493&fit=crop&dpr=1 754w, https://images.theconversation.com/files/377532/original/file-20210107-22-tnnrm0.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=493&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/377532/original/file-20210107-22-tnnrm0.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=493&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Changes in animal movement distances in response to different types of disturbance. Positive values mean movement was higher in disturbed compared to undisturbed areas.</span>
</figcaption>
</figure>
<p>But we found human activities caused much stronger increases in animal movement distances (averaging +35%) than habitat modifications (averaging +12%).</p>
<p>This might be because human activities are more episodic in nature. In other words, animals are more likely to run away from these unpredictable disturbances. </p>
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Read more:
<a href="https://theconversation.com/be-still-my-beating-wings-hunters-kill-migrating-birds-on-their-10-000km-journey-to-australia-138382">Be still, my beating wings: hunters kill migrating birds on their 10,000km journey to Australia</a>
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<p>For example, <a href="https://www.sciencedirect.com/science/article/abs/pii/0006320796000043">military manoeuvres</a> in Norway led to 84% increase in the home range of moose. And when moose in Sweden were exposed to <a href="https://link.springer.com/article/10.1007/s10344-009-0340-x">back-country skiers</a>, their movement speed increased 33-fold.</p>
<p>In contrast, habitat modifications like logging generally represent more persistent changes to the environment, which animals can sometimes adapt to over time. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/381242/original/file-20210129-17-1hs5nv0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Moose head behind green bushes" src="https://images.theconversation.com/files/381242/original/file-20210129-17-1hs5nv0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/381242/original/file-20210129-17-1hs5nv0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/381242/original/file-20210129-17-1hs5nv0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/381242/original/file-20210129-17-1hs5nv0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/381242/original/file-20210129-17-1hs5nv0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/381242/original/file-20210129-17-1hs5nv0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/381242/original/file-20210129-17-1hs5nv0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&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">Human activities can lead to huge changes in the movement of animals, such as moose.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
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<h2>Reducing harms on wildlife</h2>
<p>To reduce the harms we inflict on wildlife, we must protect habitats in relatively intact sea and landscapes from getting degraded or transformed. This could include establishing and managing new national parks and marine protected areas. </p>
<p>Where ecosystems are already modified, improving the connections between habitats and the availability of resources (food and water) can <a href="https://royalsocietypublishing.org/doi/full/10.1098/rspb.2017.2272">help animals move</a> more easily and populations persist.</p>
<p>And with regards to human activities, which generally caused stronger increases in movement, better managing disturbances such as hunting, recreation and tourism can help to minimise or avoid impacts on animal movement. This could include, for example, establishing a no-take zone in a <a href="https://www.sciencedirect.com/science/article/abs/pii/S0006320716301367">marine protected area</a>, or enforcing restrictions to activities during breeding periods. </p>
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Read more:
<a href="https://theconversation.com/the-buffel-kerfuffle-how-one-species-quietly-destroys-native-wildlife-and-cultural-sites-in-arid-australia-149456">The buffel kerfuffle: how one species quietly destroys native wildlife and cultural sites in arid Australia</a>
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<img src="https://counter.theconversation.com/content/152619/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Tim Doherty receives funding from the Australian Research Council, Hermon Slade Foundation, Australian Academy of Science and NSW Environmental Trust. He is Chair of the Policy Committee for the Society for Conservation Biology Oceania and a member of the Ecological Society of Australia.</span></em></p><p class="fine-print"><em><span>Don Driscoll receives funding from the Herman Slade Foundation, OEH NSW Environmental Grants program, DELWP Vic, National Geographic, Rufford Foundation, WWF and Bushfire and Natural Hazards CRC. He is Director of the Centre of Integrative Ecology and Director of the TechnEcology Research Network at Deakin University. Don is a member of the Ecological Society of Australia and Society for Conservation Biology.</span></em></p><p class="fine-print"><em><span>Graeme Hays receives funding from the Bertarelli Programme in Marine Science. </span></em></p>World-first research finds human disturbances, on average, restrict an animal’s movements by 37%, or increase it by 70%. That’s like needing to travel an extra 11 km to get to work each day.Tim Doherty, ARC DECRA Fellow, University of SydneyDon Driscoll, Professor in Terrestrial Ecology, Deakin UniversityGraeme Hays, Professor of Marine Science, Deakin UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1220082019-08-29T18:03:04Z2019-08-29T18:03:04ZSurveying archaeologists across the globe reveals deeper and more widespread roots of the human age, the Anthropocene<figure><img src="https://images.theconversation.com/files/289131/original/file-20190822-170914-ejab20.JPG?ixlib=rb-1.1.0&rect=3%2C15%2C2445%2C1737&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">People have been modifying Earth – as in these rice terraces near Pokhara, Nepal – for millennia.</span> <span class="attribution"><span class="source">Erle C. Ellis</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>Examples of how human societies are changing the planet abound – from building roads and houses, clearing forests for agriculture and digging train tunnels, to shrinking the ozone layer, driving species extinct, changing the climate and acidifying the oceans. Human impacts are everywhere. Our societies have changed Earth so much that it’s <a href="https://doi.org/10.1073/pnas.1810141115">impossible to reverse many of these effects</a>. </p>
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<a href="https://images.theconversation.com/files/289249/original/file-20190823-170951-fay4qj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/289249/original/file-20190823-170951-fay4qj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/289249/original/file-20190823-170951-fay4qj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=722&fit=crop&dpr=1 600w, https://images.theconversation.com/files/289249/original/file-20190823-170951-fay4qj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=722&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/289249/original/file-20190823-170951-fay4qj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=722&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/289249/original/file-20190823-170951-fay4qj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=908&fit=crop&dpr=1 754w, https://images.theconversation.com/files/289249/original/file-20190823-170951-fay4qj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=908&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/289249/original/file-20190823-170951-fay4qj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=908&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">Nuclear bomb testing left its mark in the geologic record.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Ivy_King_-_mushroom_cloud.jpg">National Nuclear Security Administration/Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
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<p>Some researchers believe these changes are so big that they mark the beginning of a new “human age” of Earth history, the <a href="https://doi.org/10.1038/d41586-019-02381-2">Anthropocene epoch</a>. A <a href="http://quaternary.stratigraphy.org/working-groups/anthropocene/">committee of geologists</a> has now proposed to mark the start of the Anthropocene in the mid-20th century, based on a striking indicator: the <a href="https://doi.org/10.1038/d41586-019-01641-5">widely scattered radioactive dust</a> from nuclear bomb tests in the early 1950s.</p>
<p>But this is not the final word.</p>
<p><a href="https://www.theatlantic.com/science/archive/2019/08/arrogance-anthropocene/595795/">Not everyone</a> is sure that today’s industrialized, globalized societies will be around long enough to define a new geological epoch. Perhaps we are just a flash in the pan – an event – rather than a long, enduring epoch. </p>
<p><a href="https://www.theatlantic.com/science/archive/2019/04/great-debate-over-when-anthropocene-started/587194/">Others debate</a> the utility of picking a single thin line in Earth’s geological record to mark the start of human impacts in the geological record. Maybe the Anthropocene <a href="https://theconversation.com/scientists-still-dont-understand-the-anthropocene-and-theyre-going-about-it-the-wrong-way-70017">began at different times</a> in different parts of the world. For example, the first instances of agriculture emerged at different places at different times, and resulted in huge impacts on the environment, through land clearing, habitat losses, extinctions, erosion and <a href="https://doi.org/10.1038/s41598-018-28419-5">carbon emissions</a>, forever <a href="https://doi.org/10.1016/j.quascirev.2009.05.022">changing the global climate</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/289132/original/file-20190822-170906-v68d5h.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/289132/original/file-20190822-170906-v68d5h.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/289132/original/file-20190822-170906-v68d5h.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=325&fit=crop&dpr=1 600w, https://images.theconversation.com/files/289132/original/file-20190822-170906-v68d5h.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=325&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/289132/original/file-20190822-170906-v68d5h.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=325&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/289132/original/file-20190822-170906-v68d5h.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=408&fit=crop&dpr=1 754w, https://images.theconversation.com/files/289132/original/file-20190822-170906-v68d5h.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=408&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/289132/original/file-20190822-170906-v68d5h.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=408&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Human practices like burning the landscape – as in this night bush fire outside Kabwe, Zambia – have been affecting the Earth since long before the nuclear era.</span>
<span class="attribution"><span class="source">Andrea Kay</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>If there are multiple beginnings, scientists need to answer more complicated questions – like when did agriculture begin to transform landscapes in different parts of the world? This is a tough question because archaeologists tend to focus their research on a limited number of sites and regions and to prioritize locations where agriculture is believed to have appeared earliest. To date, it has proved nearly impossible for archaeologists to put together a global picture of land use changes throughout time.</p>
<h2>Global answers from local experts</h2>
<p>To tackle these questions, we pulled together a <a href="http://globe.umbc.edu/archaeoglobe/">research collaboration</a> among archaeologists, anthropologists and geographers to survey archaeological knowledge on land use across the planet.</p>
<p>We asked over 1,300 archaeologists from around the world to contribute their knowledge on how ancient people used the land in 146 regions spanning all continents except Antarctica from 10,000 years ago right up to 1850. More than 250 responded, representing the largest expert archaeology crowdsourcing project ever undertaken, though some <a href="https://crowdsourced.micropasts.org/">prior</a> <a href="https://www.globalxplorer.org/">projects</a> have worked with amateur contributions.</p>
<p><a href="http://doi.org/10.1126/science.aax1192">Our work</a> has now mapped the current state of archaeological knowledge on land use across the planet, including parts of the world that have rarely been considered in previous studies.</p>
<p>We used a crowdsourcing approach because <a href="https://doi.org/10.1017/aap.2018.3">scholarly publications don’t always include the original data</a> needed to allow global comparisons. Even when these data are shared by archaeologists, they use many different formats from one project to another, making it difficult to combine for large-scale analysis. Our goal from the beginning was to make it easy for anyone to check our work and reuse our data – we’ve <a href="https://dataverse.harvard.edu/dataverse/ArchaeoGLOBE">put all our research materials online</a> where they can be freely accessed by anyone.</p>
<h2>Earlier and more widespread human impacts</h2>
<p>Though our study acquired expert archaeological information from across the planet, data were more available in some regions – including Southwest Asia, Europe, northern China, Australia and North America – than in others. This is probably because more archaeologists have worked in these regions than elsewhere, such as parts of Africa, Southeast Asia and South America.</p>
<figure>
<img src="https://cdn.theconversation.com/static_files/files/690/ArchaeoGLOBE_INAG.gif?1566501861">
<figcaption><span class="caption">Animation showing the spread of intensive agriculture across the globe over the past 10,000 years, based on ArchaeoGLOBE Project results. (Nicolas Gauthier, 2019, CC-BY-SA)</span></figcaption>
</figure>
<p>Our archaeologists reported that nearly half (42%) of our regions had some form of agriculture by 6,000 years ago, highlighting the prevalence of agricultural economies across the globe. Moreover, these results indicate that the onset of agriculture was earlier and more widespread than suggested in the most common global reconstruction of land-use history, the <a href="https://doi.org/10.1177/0959683609356587">History Database of the Global Environment</a>. This is important because climate scientists often use this database of past conditions to estimate future climate change; according to our research it may be underestimating land-use-associated climate effects.</p>
<p>Our survey also revealed that hunting and foraging was generally replaced by pastoralism (raising animals such as cows and sheep for food and other resources) and agriculture in most places, though there were exceptions. In a few areas, reversals occurred and agriculture did not simply replace foraging but merged with it and <a href="https://doi.org/10.1007/s10963-019-09131-2">coexisted side by side for some time</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/289133/original/file-20190822-170918-n7j523.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/289133/original/file-20190822-170918-n7j523.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/289133/original/file-20190822-170918-n7j523.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=225&fit=crop&dpr=1 600w, https://images.theconversation.com/files/289133/original/file-20190822-170918-n7j523.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=225&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/289133/original/file-20190822-170918-n7j523.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=225&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/289133/original/file-20190822-170918-n7j523.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=282&fit=crop&dpr=1 754w, https://images.theconversation.com/files/289133/original/file-20190822-170918-n7j523.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=282&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/289133/original/file-20190822-170918-n7j523.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=282&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">View of the Kopaic Plain in Boeotia, Greece. People first partially drained the area 3,300 years ago to claim land for agriculture and it’s still farmed today.</span>
<span class="attribution"><span class="source">Lucas Stephens</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<h2>The deep roots of the Anthropocene</h2>
<p>Global archaeological data show that human transformation of environments began at different times in different regions and accelerated with the emergence of agriculture. Nevertheless, by 3,000 years ago, most of the planet was already transformed by hunter-gatherers, farmers and pastoralists.</p>
<p>To guide this planet toward a better future, we need to understand how we got here. The message from archaeology is clear. It took thousands of years for the pristine planet of long ago to become the human planet of today.</p>
<p>And there is no way to fully understand this human planet <a href="https://scholarcommons.scu.edu/cgi/viewcontent.cgi?article=1051&context=anthro_fac_pubs">without building on the expertise of archaeologists</a>, anthropologists, sociologists <a href="https://theconversation.com/scientists-still-dont-understand-the-anthropocene-and-theyre-going-about-it-the-wrong-way-70017">and other human scientists</a>. To build a more robust Earth science in the Anthropocene, the human sciences must play as central a role as the natural sciences do today.</p>
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<section class="inline-content">
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<p><a href="http://www.aag.org">Erle C. Ellis is a member of the American Association of Geographers</a></p>
<footer>The association is a funding partner of The Conversation US.</footer>
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</section>
</p>
<p>[ <em>Like what you’ve read? Want more?</em> <a href="https://theconversation.com/us/newsletters?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=likethis">Sign up for The Conversation’s daily newsletter</a>. ]</p><img src="https://counter.theconversation.com/content/122008/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Ben Marwick receives funding from the Australian Research Council, the Wenner-Gren Foundation, and the National Geographic Society </span></em></p><p class="fine-print"><em><span>Erle C. Ellis received funding from the National Science Foundation for this project under grant CNS 1125210. He is a fellow of the Global Land Program, a member of the Anthropocene Working Group of the International Commission on Stratigraphy, and a senior fellow of the Breakthrough Institute. He is a member of the American Association of Geographers.</span></em></p><p class="fine-print"><em><span>Lucas Stephens receives funding from the American Council of Learned Societies. He is a Mellon/ACLS Public Fellow and Senior Research Analyst at the Environmental Law and Policy Center and a Research Affiliate at the Max Planck Institute for the Science of Human History. </span></em></p><p class="fine-print"><em><span>Nicole Boivin receives funding from the Max Planck Society. She is Director at the Max Planck Institute for the Science of Human History, an Honorary Professor at the University of Queensland, and a Research Affiliate at the Smithsonian Institution and University of Calgary.</span></em></p>Hundreds of archaeologists provided on-the-ground data from across the globe, providing a new view of the long and varied history of people transforming Earth’s environment.Ben Marwick, Associate Professor of Archaeology, University of WashingtonErle C. Ellis, Professor of Geography and Environmental Systems, University of Maryland, Baltimore CountyLucas Stephens, Research Affiliate in Archaeology, Max Planck Institute of GeoanthropologyNicole Boivin, Director of the Department of Archaeology, Max Planck Institute of GeoanthropologyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1200652019-07-24T11:07:49Z2019-07-24T11:07:49ZResource depletion is a serious problem, but ‘footprint’ estimates don’t tell us much about it<figure><img src="https://images.theconversation.com/files/285413/original/file-20190723-110195-1gcmce8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Government negligence, rampant development and illegal land clearing spark wildfires in Indonesia that annually ravage thousands of acres of forest.</span> <span class="attribution"><a class="source" href="http://www.apimages.com/metadata/Index/AP10ThingsToSee-Indonesia-Wildfires/1cf055c1810b40ce92e05d28c680e4f7/7/0">AP Photo</a></span></figcaption></figure><p>Experts widely agree that human activities are harming the global environment. Since the Industrial Revolution, the world economy has grown dramatically. Overall this is a success story, since rising incomes have lifted millions of people out of poverty. But it has been fueled by population growth and increasing consumption of natural resources. </p>
<p>Rising demand to meet the needs of <a href="https://www.prb.org/2018-world-population-data-sheet-with-focus-on-changing-age-structures/">more than 7.6 billion people</a> has transformed land use and generated unprecedented levels of pollution, affecting biodiversity, forests, wetlands, water bodies, soils and air quality.</p>
<p>It’s pretty certain that humans are consuming more resources than the Earth can regenerate. An updated estimate of how fast that consumption is happening suggests it’s more rapid this year than in the past 50, according to the California-based <a href="https://www.footprintnetwork.org/">Global Footprint Network</a>. This environmental nonprofit calculates the annual arrival of <a href="https://www.overshootday.org/">Earth Overshoot Day</a> – the date when humanity’s demands on nature exceed what the network’s analysts estimate the Earth can regenerate over the entire year. This year they peg the date as July 29 – the earliest date since ecological overshoot began in the early 1970s. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/285411/original/file-20190723-110179-mzcnot.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/285411/original/file-20190723-110179-mzcnot.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/285411/original/file-20190723-110179-mzcnot.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=376&fit=crop&dpr=1 600w, https://images.theconversation.com/files/285411/original/file-20190723-110179-mzcnot.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=376&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/285411/original/file-20190723-110179-mzcnot.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=376&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/285411/original/file-20190723-110179-mzcnot.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=473&fit=crop&dpr=1 754w, https://images.theconversation.com/files/285411/original/file-20190723-110179-mzcnot.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=473&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/285411/original/file-20190723-110179-mzcnot.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=473&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="attribution"><a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
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<p>As an ecological economist and <a href="https://scholar.google.com/citations?user=fCsfSRkAAAAJ&hl=en">scholar of sustainability</a>, I am particularly interested in metrics and indicators that can help us understand human uses of Earth’s ecosystems. Better measurements of the impacts of human activities can help identify ways to sustain both human well-being and natural resources. </p>
<p>Earth Overshoot Day is a compelling concept and has raised awareness of the growing impact of human activities on the planet. Unfortunately, the methodology used to calculate it and the ecological footprint on which it is based is conceptually flawed and practically unusable in any science or policy context. In my view, the ecological footprint ultimately does not measure overuse of natural resources – and it may very well underestimate it.</p>
<h2>Rising demands, finite resources</h2>
<p>The Global Footprint Network estimates when Earth Overshoot Day will arrive based on its <a href="https://www.footprintnetwork.org/resources/data/">National Footprint Accounts</a>. These include extensive data sets that the organization uses to calculate two overarching indicators: </p>
<ul>
<li><p>The ecological footprint, perhaps the most commonly used metric of the environmental impacts of human resource use. Each country’s ecological footprint is an estimate of the biological resources required to meet its population’s consumption demands and absorb its carbon emissions. </p></li>
<li><p>National biocapacity, which is an estimate of how well each country’s ecosystems can produce the natural resources consumed by humans and absorb the waste and pollution that humans generate. </p></li>
</ul>
<p>Both of these measures are expressed in global hectares. One hectare is equal to 10,000 square meters, or about 2.47 acres. </p>
<h2>Going into overshoot</h2>
<p>To estimate when Earth Overshoot Day will arrive, the Global Footprint Network calculates the number of days in a given year for which Earth has enough biocapacity to provide for humans’ total ecological footprint. </p>
<p>When the footprint of consumption worldwide exceeds biocapacity, the authors assert that humans are overshooting, or exceeding the regenerative capacity of Earth’s ecosystems. This year, they estimate that humans are using natural resources 1.75 times faster than ecosystems can regenerate – or, put another way, consuming 1.75 Earths.</p>
<p>As an example, the ecological footprint for the United Kingdom is 4.4 global hectares per person, and global biocapacity is 1.63 hectares per person. Therefore, it would take (4.4 /1.63) 2.7 Earths if everyone lived like the British.</p>
<p>The U.K.’s Overshoot Day would be estimated as 365 x (1.63 /4.4) = 135, or the 135th day of the year, which is May 17 based on <a href="http://data.footprintnetwork.org/#/compareCountries">2016 data</a>. The United States reached overshoot even earlier, on March 15.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"930416274928295937"}"></div></p>
<h2>What to count?</h2>
<p>However, there are some fundamental and misleading shortcomings in these calculations. In a <a href="https://doi.org/10.1371/journal.pbio.1001700">2013 paper</a>, six authors from academia, <a href="https://www.nature.org/">The Nature Conservancy</a> and the California-based <a href="https://thebreakthrough.org/about">Breakthrough Institute</a> analyzed how the Ecological Footprint falls short. In their view, it primarily measures humans’ carbon footprint but does not fully address other key impacts.</p>
<p>To calculate ecological footprints, the Global Footprint Network estimates the supply and demand of renewable biological resources across six land use types: forests, fishing grounds, croplands, grazing lands, developed lands and the area of forest required to offset human carbon emissions – that is, the carbon footprint. According to the network’s own analysis, each of these land use types is nearly in balance or in surplus, except for the carbon footprint.</p>
<p>The two key categories for producing food – cropland and grazing land – are defined in such a way that they can never be in deficit. And the analysis does not reflect environmental consequences of human use of these lands, such as soil erosion, nutrient runoff or overuse of water. It measures only land area.</p>
<p>For example, the ecological footprint for Indonesia is 1.7 global hectares per person, which is among the lowest 30% of all countries. But according to a 2014 study, Indonesia has the <a href="https://doi.org/10.1038/nclimate2277">highest deforestation rate in the world</a>.</p>
<p>Furthermore, the footprint calculation does not consider whether stocks of natural resources are decreasing or increasing as a result of human consumption. This question is critical for understanding ecological impacts. </p>
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<figcaption><span class="caption">Is shopping online better for the environment than driving to the store? Yes, but only if you don’t choose express delivery.</span></figcaption>
</figure>
<p>These national ecological footprint calculations also conflate sustainability with self-sufficiency. They assume that every nation should produce all of the resources it consumes, even though it might be less expensive for countries to import some goods than to produce them at home. </p>
<p>As an example, the network lists Canada as an <a href="http://data.footprintnetwork.org/#/">“ecological creditor”</a> whose biocapacity exceeds its population’s ecological footprint. However, Canada is <a href="https://www.eia.gov/beta/international/">among the top 5 oil-producing countries in the world</a>, and exports much of that oil for foreign consumption. Most of it goes to the United States, an “ecological debtor” that consumes more resources than it produces. </p>
<p>Thinking purely in terms of generic “resources,” everyone is better off when debtor countries can import resources from nations with supplies to spare. There are real and important environmental impacts associated with producing and consuming oil, but the network’s calculations do not address them. Nor do they reflect the decline in natural capital from extracting a nonrenewable resource.</p>
<h2>Measuring sustainability</h2>
<p>The Global Footprint Network asserts that “You can’t manage what you can’t measure,” but it may be impossible to create a single metric that can capture all human impacts on the environment. Earth Overshoot Day highlights unsustainable uses of natural resources, but we need scientifically robust ecological indicators to inform environmental policy, and a broader understanding of ecological risks.</p>
<p>Better measurements of sustainability should reflect changes in our supplies of natural capital, include estimates of uncertainty and incorporate multiple pathways to reduce carbon footprints. The best tool for measuring human impacts on the planet may be a dashboard of environmental indicators, not a footprint.</p><img src="https://counter.theconversation.com/content/120065/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Robert B. Richardson is affiliated with the International Society for Ecological Economics, and is currently President of the U.S. Society for Ecological Economics. </span></em></p>July 29, 2019 is ‘Earth Overshoot Day,’ a date coined by the nonprofit Global Footprint Network to publicize overuse of Earth’s resources. But their estimates may actually understate the problem.Robert B. Richardson, Professor of Sustainable Development, Michigan State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1133612019-03-12T19:08:32Z2019-03-12T19:08:32ZGuns, snares and bulldozers: new map reveals hotspots for harm to wildlife<figure><img src="https://images.theconversation.com/files/263334/original/file-20190312-86699-k7wj98.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Human activity threatens many species across Africa’s savannahs.</span> <span class="attribution"><span class="source">Paul Mulondo/WCS</span>, <span class="license">Author provided</span></span></figcaption></figure><p>The <a href="https://theconversation.com/hunting-fishing-and-farming-remain-the-biggest-threats-to-wildlife-63723">biggest killers</a> of wildlife globally are unsustainable hunting and harvesting, and the conversion of huge swathes of natural habitat into farms, housing estates, roads and other industrial activities. There is little doubt that these threats are driving the current mass extinction crisis.</p>
<p>Yet our understanding of where these threats overlap with the locations of sensitive species has been poor. This limits our ability to target conservation efforts to the most important places.</p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/earths-wilderness-is-vanishing-and-just-a-handful-of-nations-can-save-it-106072">Earth’s wilderness is vanishing, and just a handful of nations can save it</a>
</strong>
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<hr>
<p>In our new study, <a href="https://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.3000158">published today in Plos Biology</a>, we mapped 15 of the most harmful human threats – including hunting and land clearing – within the locations of 5,457 threatened mammals, birds and amphibians globally. </p>
<p>We found that 1,237 species – a quarter of those assessed – are impacted by threats that cover more than 90% of their distributions. These species include many large, charismatic mammals such as lions and elephants. Most concerningly of all, we identified 395 species that are impacted by threats across 100% of their range. </p>
<h2>Mapping the risks</h2>
<p>We only mapped threats within a species location if those threats are known to specifically endanger that species. For example, the <a href="https://www.iucnredlist.org/species/15951/115130419">African lion</a> is threatened by urbanisation, hunting and trapping, so we only quantified the overlap of those specific hazards for this species. </p>
<p>This allowed us to determine the parts of a species’ home range that are impacted by threats and, conversely, the parts that are free of threats and therefore serve as refuges. </p>
<p>We could then identify global hotspots of human impacts on threatened species, as well as “coolspots” where species are largely threat-free.</p>
<p>The fact that so many species face threats across almost all of their range has grave consequences. These species are likely to continue to decline and possibly die out in the impacted parts of their ranges. Completely impacted species certainly face extinction without targeted conservation action. </p>
<p>Conversely, we found more than 1,000 species that were not impacted by human threats at all. Although this is positive news, it is important to note that we have not mapped every possible threat, so our results likely underestimate the true impact. For example, we didn’t account for diseases, which are a major threat to amphibians, or climate change, which is a major threat to virtually all species.</p>
<h2>Hotspots and coolspots</h2>
<p>We produced the first global map of human impacts on threatened species by combining the parts of each species range that are exposed to threats.
The overwhelmingly dominant global hotspot for human impacts on threatened species is Southeast Asia. </p>
<p>This region contains the top five countries with the most threats to species.
These include Malaysia, Brunei, Singapore, Indonesia and Myanmar. </p>
<p>The most impacted ecosystems include mangroves and tropical forests, which concerningly are home to the greatest diversity of life on Earth.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/263308/original/file-20190312-86707-sab6nr.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/263308/original/file-20190312-86707-sab6nr.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/263308/original/file-20190312-86707-sab6nr.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=397&fit=crop&dpr=1 600w, https://images.theconversation.com/files/263308/original/file-20190312-86707-sab6nr.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=397&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/263308/original/file-20190312-86707-sab6nr.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=397&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/263308/original/file-20190312-86707-sab6nr.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=499&fit=crop&dpr=1 754w, https://images.theconversation.com/files/263308/original/file-20190312-86707-sab6nr.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=499&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/263308/original/file-20190312-86707-sab6nr.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=499&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Hotspots of threats and threatened species richness.</span>
<span class="attribution"><span class="source">Allan et al. Plos Biol.</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>We also created a global map of coolspots by combining the parts of species ranges that are free from human threats. This map identifies the last vestiges of wild places where threatened species have shelter from the ravages of guns, snares and bulldozers. As such, these are crucial conservation strongholds.</p>
<p>Coolspots include parts of the Amazon rainforest, the Andes, the eastern Himalayas, and the forests of Liberia in West Africa. </p>
<p>In many places, coolspots are located near hotspots. This makes sense because in species-rich areas it is likely that many animals are impacted whereas many others are not, due to their varying sensitivity to different threats.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/263309/original/file-20190312-86690-vcmp9g.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/263309/original/file-20190312-86690-vcmp9g.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/263309/original/file-20190312-86690-vcmp9g.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=394&fit=crop&dpr=1 600w, https://images.theconversation.com/files/263309/original/file-20190312-86690-vcmp9g.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=394&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/263309/original/file-20190312-86690-vcmp9g.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=394&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/263309/original/file-20190312-86690-vcmp9g.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=495&fit=crop&dpr=1 754w, https://images.theconversation.com/files/263309/original/file-20190312-86690-vcmp9g.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=495&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/263309/original/file-20190312-86690-vcmp9g.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=495&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Coolspots of unimpacted species richness.</span>
<span class="attribution"><span class="source">Allan et al. Plos Biol.</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>What next?</h2>
<p>There is room for optimism because all the threats we map can be stopped by conservation action. But we need to make sure this action is directed to priority areas, and that it has enough financial and political support.</p>
<p>An obvious first step is to secure threat-free refuges for particular species, via actions such as protected areas, which are paramount for their survival. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/an-end-to-endings-how-to-stop-more-australian-species-going-extinct-111627">An end to endings: how to stop more Australian species going extinct</a>
</strong>
</em>
</p>
<hr>
<p>To ensure the survival of highly impacted species with little or no access to refuges, “active threat management” is needed to open enough viable habitat for them to survive. For example, tiger numbers in Nepal have <a href="https://www.cambridge.org/core/journals/oryx/article/rapid-recovery-of-tigers-panthera-tigris-in-parsa-wildlife-reserve-nepal/63B4780218511C5EC5FBC72E0AD28216">doubled since 2009</a>, mainly as a result of targeted anti-poaching efforts. </p>
<p>Tackling threats and protecting refuges are complementary approaches that will be most effective if carried out simultaneously. Our study provides information that can help guide these efforts and help to make national and global conservation plans as successful as possible.</p>
<hr>
<p><em>The authors acknowledge the contributions of <a href="https://theconversation.com/profiles/hugh-possingham-3107">Hugh Possingham</a>, <a href="https://theconversation.com/profiles/oscar-venter-299194">Oscar Venter</a>, <a href="https://theconversation.com/profiles/moreno-di-marco-321921">Moreno Di Marco</a> and <a href="https://theconversation.com/profiles/scott-consaul-atkinson-405519">Scott Consaul Atkinson</a> to the research on which this article is based.</em></p><img src="https://counter.theconversation.com/content/113361/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Christopher O'Bryan receives funding from the Invasive Animals Cooperative Research Centre and an Australian International Research Scholarship. He is a PhD candidate and research assistant at the University of Queensland.</span></em></p><p class="fine-print"><em><span>James Watson receives funding from Australian Research Council and National Environmental Science Program. He is Director of Science at the Wildlife Conservation Society and past global president of the Society for Conservation Biology. </span></em></p><p class="fine-print"><em><span>James Allan 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>New research looked at human impacts on more than 5,000 threatened species and found that a quarter of them have almost nowhere left to go to escape from the threats posed by human development.James Allan, Postdoctoral research fellow, School of Biological Sciences, The University of QueenslandChristopher J. O'Bryan, PhD Candidate, School of Earth and Environmental Sciences, The University of QueenslandJames Watson, Professor, The University of QueenslandLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1007052018-07-30T15:51:42Z2018-07-30T15:51:42ZYes, humans are depleting Earth’s resources, but ‘footprint’ estimates don’t tell the full story<figure><img src="https://images.theconversation.com/files/229654/original/file-20180727-106524-17wl00g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Purse seiner fishing in the Indian Ocean. Footprint estimates do not assess how sustainably resources such as fisheries are managed.</span> <span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:GP04JLI.jpg">Jiri Rezac</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>Experts widely agree that human activities are harming the global environment. Since the Industrial Revolution, the world economy has grown dramatically. Overall this is a success story, since rising incomes have lifted millions of people out of poverty. But it has been fueled by population growth and increasing consumption of natural resources. </p>
<p>Rising demand to meet the needs of <a href="https://theconversation.com/7-5-billion-and-counting-how-many-humans-can-the-earth-support-98797">more than 7 billion people</a> has transformed land use and generated unprecedented levels of pollution, affecting biodiversity, forests, wetlands, water bodies, soils and air quality.</p>
<p>On Aug. 1, humans will have consumed more natural resources in 2018 than the Earth can regenerate this year, according to the California-based <a href="https://www.footprintnetwork.org/">Global Footprint Network</a>. This environmental nonprofit calculates the annual arrival of <a href="https://www.overshootday.org/">Earth Overshoot Day</a> – the date when humanity’s demands on nature exceed what the network’s analysts estimate the Earth can regenerate over the entire year. Aug. 1 is the earliest date since ecological overshoot began in the early 1970s. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/229645/original/file-20180727-106527-11vhdj2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/229645/original/file-20180727-106527-11vhdj2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/229645/original/file-20180727-106527-11vhdj2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=376&fit=crop&dpr=1 600w, https://images.theconversation.com/files/229645/original/file-20180727-106527-11vhdj2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=376&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/229645/original/file-20180727-106527-11vhdj2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=376&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/229645/original/file-20180727-106527-11vhdj2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=473&fit=crop&dpr=1 754w, https://images.theconversation.com/files/229645/original/file-20180727-106527-11vhdj2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=473&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/229645/original/file-20180727-106527-11vhdj2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=473&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Aug. 1 is the earliest arrival of Earth Overshoot Day since humans started overusing the planet’s resources in the 1970s.</span>
<span class="attribution"><a class="source" href="https://www.overshootday.org/">Global Footprint Network</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>As an ecological economist and <a href="https://scholar.google.com/citations?user=fCsfSRkAAAAJ&hl=en">scholar</a> of sustainability, I am particularly interested in metrics and indicators that can help us understand human uses of Earth’s ecosystems. Better measurements of the impacts of human activities can help identify ways to sustain both human well-being and natural resources. </p>
<p>Earth Overshoot Day is a compelling concept and has raised awareness of the growing impact of human activities on the planet. Unfortunately, the methodology used to calculate it and the ecological footprint on which it is based is conceptually flawed and practically unusable in any science or policy context. In my view, the ecological footprint ultimately does not measure overuse of natural resources – and it may very well underestimate it.</p>
<h2>Rising demands, finite resources</h2>
<p>The Global Footprint Network estimates when Earth Overshoot Day will arrive based on its <a href="https://www.footprintnetwork.org/resources/data/">National Footprint Accounts</a>. These include extensive data sets that the organization uses to calculate two overarching indicators: </p>
<ul>
<li><p>The ecological footprint, perhaps the most commonly used metric of the environmental impacts of human resource use. Each country’s ecological footprint is an estimate of the biological resources required to meet its population’s consumption demands and absorb its carbon emissions. </p></li>
<li><p>National biocapacity, which is an estimate of how well each country’s ecosystems can produce the natural resources consumed by humans and absorb the waste and pollution that humans generate. </p></li>
</ul>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/_T5M3MiPfW4?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The Global Footprint Network’s National Footprint Accounts compare countries’ annual demand for goods and services to the resources they produce.</span></figcaption>
</figure>
<p>Both of these measures are expressed in global hectares. One hectare is equal to 10,000 square meters, or about 2.47 acres. </p>
<h2>Going into overshoot</h2>
<p>To estimate when Earth Overshoot Day will arrive, the Global Footprint Network calculates the number of days in a given year for which Earth has enough biocapacity to provide for humans’ total ecological footprint. The rest of the year represents “global overshoot.” </p>
<p>When the footprint of consumption worldwide exceeds biocapacity, the authors assert that humans are exceeding the regenerative capacity of Earth’s ecosystems. This year, they estimate that humans are using natural resources 1.7 times faster than ecosystems can regenerate – or, put another way, consuming 1.7 Earths.</p>
<p>As an example, the ecological footprint for France is 4.7 global hectares per person, and global biocapacity is 1.7 hectares per person. Therefore, it would take (4.7/ 1.7 =) 2.8 Earths if everyone lived like the French.</p>
<p>France’s Overshoot Day would be estimated as (365 x (1.7/ 4.7)) = 130, or the 130th day of the year, which is May 5 based on <a href="http://data.footprintnetwork.org/#/compareCountries">2014 data</a>. The United States reached overshoot even earlier, on March 15.</p>
<h2>What to count?</h2>
<p>However, there are some fundamental and misleading shortcomings in these calculations. In a 2013 <a href="https://doi.org/10.1371/journal.pbio.1001700">paper</a>, six authors from academia, <a href="https://www.nature.org/">The Nature Conservancy</a> and the California-based <a href="https://thebreakthrough.org/about">Breakthrough Institute</a> analyzed how the Ecological Footprint falls short. In their view, it primarily measures humans’ carbon footprint but does not address other key impacts.</p>
<p>To calculate ecological footprints, the Global Footprint Network estimates the supply and demand of renewable biological resources across six land use types: forests, fishing grounds, croplands, grazing lands, developed lands and the area of forest required to offset human carbon emissions – that is, the carbon footprint. According to the network’s own analysis, each of these land use types is nearly in balance or in surplus, except for the carbon footprint. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/229650/original/file-20180727-106527-110bkma.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/229650/original/file-20180727-106527-110bkma.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/229650/original/file-20180727-106527-110bkma.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/229650/original/file-20180727-106527-110bkma.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/229650/original/file-20180727-106527-110bkma.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/229650/original/file-20180727-106527-110bkma.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/229650/original/file-20180727-106527-110bkma.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/229650/original/file-20180727-106527-110bkma.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">Conventional tillage leaves fields in South Dakota vulnerable to erosion. Impacts like this are not captured in footprint calculations that focus on quantifying resources.</span>
<span class="attribution"><a class="source" href="https://flic.kr/p/oaBaKH">USDA NRCS South Dakota</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>The two key categories for producing food – cropland and grazing land – are defined in such a way that they can never be in deficit. And the analysis does not reflect environmental consequences of human use of these lands, such as soil erosion, nutrient runoff or overuse of water. It measures only land area.</p>
<p>For example, the ecological footprint for Indonesia is 1.61 global hectares per person, which is among the lowest 30 percent of all countries. But according to a 2014 <a href="https://doi.org/10.1038/nclimate2277">study</a>, Indonesia has the highest deforestation rate in the world.</p>
<p>Furthermore, the footprint calculation does not consider whether stocks of natural resources are decreasing or increasing as a result of human consumption. This question is critical for understanding ecological impacts. </p>
<p>These national ecological footprint calculations also conflate sustainability with self-sufficiency. They assume that every nation should produce all of the resources it consumes, even though it might be less expensive for countries to import some goods than to produce them at home. </p>
<p>As an example, the network lists Canada as an <a href="http://data.footprintnetwork.org/#/">“ecological creditor”</a> whose biocapacity exceeds its population’s ecological footprint. However, Canada is <a href="https://www.eia.gov/beta/international/">among the top 10 oil-producing countries in the world</a>, and exports much of that oil for foreign consumption. Most of it goes to the United States, an “ecological debtor” that consumes more resources than it produces. </p>
<p>Thinking purely in terms of generic “resources,” everyone is better off when debtor countries can import resources from nations with supplies to spare. There are real and important environmental impacts associated with producing and consuming oil, but the network’s calculations do not address them. Nor do they reflect the decline in natural capital from extracting a nonrenewable resource.</p>
<h2>Measuring sustainability</h2>
<p>The Global Footprint Network asserts that “You can’t manage what you can’t measure,” but it may be impossible to create a single metric that can capture all human impacts on the environment. Earth Overshoot Day highlights unsustainable uses of natural resources, but we need scientifically robust ecological indicators to inform environmental policy, and a broader understanding of ecological risks.</p>
<p>Better measurements of sustainability should reflect changes in our supplies of natural capital, include estimates of uncertainty and incorporate multiple pathways to reducing carbon footprints. The best tool for measuring human impacts on the planet may be a dashboard of environmental indicators, not a footprint.</p><img src="https://counter.theconversation.com/content/100705/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Robert B. Richardson does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>August 1, 2018 is ‘Earth Overshoot Day,’ a date coined by the nonprofit Global Footprint Network to publicize overuse of Earth’s resources. But their estimates actually understate the problem.Robert B. Richardson, Associate Professor of Sustainable Development, Michigan State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/981352018-06-14T18:01:03Z2018-06-14T18:01:03ZTo avoid humans, more wildlife now work the night shift<figure><img src="https://images.theconversation.com/files/223236/original/file-20180614-32319-1rmbjtk.jpg?ixlib=rb-1.1.0&rect=557%2C393%2C3830%2C2787&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Red fox under cover of darkness in London</span> <span class="attribution"><a class="source" href="https://www.jamiehallphotography.co.uk/index">Jamie Hall. For use only with this article.</a></span></figcaption></figure><p>For their first 100 million years on planet Earth, our mammal ancestors relied on the cover of darkness to escape their dinosaur predators and competitors. Only <a href="https://doi.org/10.1038/s41559-017-0366-5">after the meteor-induced mass extinction of dinosaurs</a> 66 million years ago could these nocturnal mammals explore the many wondrous opportunities available in the light of day.</p>
<p>Fast forward to the present, and the honeymoon in the sun may be over for mammals. They’re increasingly returning to the protection of night to avoid the Earth’s current terrifying super-predator: <em>Homo sapiens</em>.</p>
<p>My colleagues <a href="https://scholar.google.com/citations?user=L_vGm14AAAAJ&hl=en&oi=ao">and I</a> have made the first effort to measure the global effects of human disturbance on the daily activity patterns of wildlife. <a href="https://doi.org/10.1126/science.aar7121">In our new study</a> in the journal Science, we documented a powerful and widespread process by which mammals alter their behavior alongside people: Human disturbance is creating a more nocturnal natural world. </p>
<p>Many catastrophic effects of humans on wildlife communities have been well-documented: We are responsible for habitat destruction and overexploitation that have <a href="https://doi.org/10.1126/science.1251817">imperiled animal populations</a> around the world. However, just our presence alone can have important behavioral impacts on wildlife, even if these effects aren’t immediately apparent or easy to quantify. Many animals fear humans: We can be large, noisy, novel and dangerous. Animals often go out of their way to avoid encountering us. But it’s becoming more and more challenging for wildlife to seek out human-free spaces, as the human population grows and our footprint expands across the planet.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/223060/original/file-20180613-32313-kcwiu6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/223060/original/file-20180613-32313-kcwiu6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/223060/original/file-20180613-32313-kcwiu6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=397&fit=crop&dpr=1 600w, https://images.theconversation.com/files/223060/original/file-20180613-32313-kcwiu6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=397&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/223060/original/file-20180613-32313-kcwiu6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=397&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/223060/original/file-20180613-32313-kcwiu6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=499&fit=crop&dpr=1 754w, https://images.theconversation.com/files/223060/original/file-20180613-32313-kcwiu6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=499&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/223060/original/file-20180613-32313-kcwiu6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=499&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A badger explores a South London cemetery at night.</span>
<span class="attribution"><span class="source">Laurent Geslin. For use only with this article.</span></span>
</figcaption>
</figure>
<h2>Global increase in nocturnality</h2>
<p>My collaborators and I noticed a striking pattern in some of our own data from research in Tanzania, Nepal and Canada: animals from impala to tigers to grizzly bears seemed to be more active at night when they were around people. Once the idea was on our radar, we began to see it throughout the published scientific literature.</p>
<p>It appeared to be a common global phenomenon; we set out to see just how widespread this effect was. Might animals all over the world be adjusting their daily activity patterns to avoid humans in time, given that it is becoming harder to avoid us in space? </p>
<p>To explore this question, we conducted a <a href="https://doi.org/10.1038/nature25753">meta-analysis</a>, or a study of studies. We systematically scoured the published literature for peer-reviewed journal articles, reports and theses that documented the 24-hour activity patterns of large mammals. We focused on mammals because their need for plenty of space often brings them into contact with humans, and they possess traits that allow for some flexibility in their activity.</p>
<p>We needed to find examples that provided data for areas or seasons of low human disturbance – that is, more natural conditions – and high human disturbance. For example, studies compared deer activity in and out of the hunting season, grizzly bear activity in areas with and without hiking, and elephant activity inside protected areas and outside among rural settlement.</p>
<p>Based on reported data from remote camera traps, radio collars or observations, we determined each species’ nocturnality, which we defined as the percentage of the animal’s total activity that occurred between sunset and sunrise. We then quantified the difference in nocturnality between low and high disturbance to understand how animals changed their activity patterns in response to people.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/223249/original/file-20180614-32310-1xo577y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/223249/original/file-20180614-32310-1xo577y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/223249/original/file-20180614-32310-1xo577y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=612&fit=crop&dpr=1 600w, https://images.theconversation.com/files/223249/original/file-20180614-32310-1xo577y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=612&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/223249/original/file-20180614-32310-1xo577y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=612&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/223249/original/file-20180614-32310-1xo577y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=769&fit=crop&dpr=1 754w, https://images.theconversation.com/files/223249/original/file-20180614-32310-1xo577y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=769&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/223249/original/file-20180614-32310-1xo577y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=769&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">For each species, researchers compared the animals’ active periods when people are nearby to when people aren’t around. The distance between the grey and red dot pair for each animal shows how extreme the shift in nocturnality.</span>
<span class="attribution"><a class="source" href="https://doi.org/10.1126/science.aar7121">Reprinted with permission from Gaynor et al., Science 360:1232 (2018). For use only with this article.</a></span>
</figcaption>
</figure>
<p>Overall, for the 62 species in our study, mammals were <a href="https://doi.org/10.1126/science.aar7121">1.36 times as nocturnal in response to human disturbance</a>. An animal that naturally split its activity evenly between the day and night, for example, would increase its nighttime activity to 68 percent around people.</p>
<p>While we expected to find a trend toward increased wildlife nocturnality around people, we were surprised by the consistency of the results around the world. Eighty-three percent of the case studies we examined showed some increase in nocturnal activity in response to disturbance. Our finding was consistent across species, continents and habitat types. Antelope on the savanna of Zimbabwe, tapir in the Ecuadorian rainforests, bobcats in the American southwest deserts – all seemed to be doing what they could to shift their activity to the cover of darkness.</p>
<p>Perhaps most surprisingly, the pattern also held across different types of human disturbance, including activities such as hunting, hiking, mountain biking, and infrastructure such as roads, residential settlement and agriculture. Animals responded strongly to all activities, regardless of whether people actually posed a direct threat. It seems human presence alone is enough to disrupt their natural patterns of behavior. People may think our outdoor recreation leaves no trace, but our mere presence can have lasting consequences. </p>
<h2>Future of human-wildlife coexistence</h2>
<p>We don’t yet understand the consequences of this dramatic behavioral shift for individual animals or populations. Over millions of years, many of the animals included in our study have evolved adaptations to living in the daylight.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/223243/original/file-20180614-32327-i3eot0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/223243/original/file-20180614-32327-i3eot0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/223243/original/file-20180614-32327-i3eot0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=778&fit=crop&dpr=1 600w, https://images.theconversation.com/files/223243/original/file-20180614-32327-i3eot0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=778&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/223243/original/file-20180614-32327-i3eot0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=778&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/223243/original/file-20180614-32327-i3eot0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=977&fit=crop&dpr=1 754w, https://images.theconversation.com/files/223243/original/file-20180614-32327-i3eot0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=977&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/223243/original/file-20180614-32327-i3eot0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=977&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Sun bears retreat from the sunny hours when people are nearby.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/sun-bear-495966712">Hakumakuma/Shutterstock</a></span>
</figcaption>
</figure>
<p><a href="http://eol.org/pages/328074/details">Sun bears</a>, for example, are typically diurnal and sun-loving creatures; in undisturbed areas less than 20 percent of their activity occurred at the night. But they <a href="https://doi.org/10.1046/j.1523-1739.1993.07030623.x">increased their nocturnality to 90 percent</a> in areas of the Sumatran forest where intensive forest research activity created a disturbance.</p>
<p>Such diurnally adapted animals may not be as successful at finding food, avoiding predators or communicating in the darkness, which could even reduce their survival or reproduction. </p>
<p>However, because our mammalian ancestors evolved under the cover of darkness in the time of the dinosaurs, most mammal species possess traits that allow for some flexibility in their activity patterns. As long as animals are able to meet their needs during the night, they may actually thrive in human-dominated landscapes by avoiding daytime direct encounters with people that could potentially be dangerous for both parties. In Nepal, for example, <a href="https://doi.org/10.1073/pnas.1210490109">tigers and people share the exact same trails</a> in the forest at different times of day, reducing direct conflict between humans and these large carnivores. Dividing up the day, through what researchers call temporal partitioning, may be a mechanism by which people and wildlife can coexist on an ever more crowded planet.</p>
<p>An increase in nocturnality among certain species may also have far-reaching consequences for ecosystems, reshaping species interactions and cascading through food webs. In California’s Santa Cruz Mountains, <a href="https://doi.org/10.1016/j.biocon.2015.05.007">coyotes are becoming more nocturnal</a> in areas with human recreation. By analyzing coyote scat, scientists have linked this behavioral change to <a href="https://doi.org/10.1111/oik.04592">dietary shifts from diurnal to nocturnal prey</a>, with implications for small mammal communities and for competition with other predators.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/223055/original/file-20180613-32347-18lcrdn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/223055/original/file-20180613-32347-18lcrdn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/223055/original/file-20180613-32347-18lcrdn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=397&fit=crop&dpr=1 600w, https://images.theconversation.com/files/223055/original/file-20180613-32347-18lcrdn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=397&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/223055/original/file-20180613-32347-18lcrdn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=397&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/223055/original/file-20180613-32347-18lcrdn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=499&fit=crop&dpr=1 754w, https://images.theconversation.com/files/223055/original/file-20180613-32347-18lcrdn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=499&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/223055/original/file-20180613-32347-18lcrdn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=499&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">European beaver active at night in Orléans, France.</span>
<span class="attribution"><a class="source" href="https://www.eurekalert.org/jrnls/sci/pages/gaynor-06-15-18.html">Laurent Geslin. For use only with this article.</a></span>
</figcaption>
</figure>
<p>Working on this study reminded me that people aren’t alone on the planet. Even if we don’t see large mammals while we’re out and about during the day, they may still be living alongside us, asleep while we are awake and vice versa. In areas where threatened species live, managers may consider restricting human activity to certain times of the day, leaving some daylight just for wildlife.</p>
<p>And it is likely that we need to preserve wilderness areas entirely free of human disturbance to conserve the most vulnerable and sensitive mammal species. Not all animals are willing or able to just switch to a nocturnal lifestyle around people. Those that try to avoid human disturbance entirely may be most vulnerable to the consequences of the expanding human footprint.</p><img src="https://counter.theconversation.com/content/98135/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kaitlyn Gaynor receives funding from the National Science Foundation. </span></em></p>It’s becoming harder and harder for animals to find human-free spaces on the planet. New research suggests that to try to avoid people, mammals are shifting activity from the day to the nighttime.Kaitlyn Gaynor, Ph.D. Candidate in Environmental Science, Policy and Management, University of California, BerkeleyLicensed as Creative Commons – attribution, no derivatives.