New Study Is First to Demonstrate That Biodiversity Inoculates Against Extinction
By Jason Bittel
Biodiversity has long been touted as important for staving off extinction. The more kinds of critters you have, in other words, the less likely any one of them—or a whole bunch of them—will disappear forever.
The trouble is, no one has ever really demonstrated this idea in a lab setting. Until now.
In a study published this month in Proceedings of the National Academy of Sciences, Dirk Sanders of the University of Exeter in the United Kingdom and his coauthors show that when you remove a species from a simple community—that is, a community with fewer overall species—it can trigger extinctions in other species. What's more, the scientists provide evidence that more complex communities—those with more species—are better able to stave off the chain of events where one loss leads to another and another. Scientists refer to this phenomenon as an extinction cascade.
Why should biodiversity be a buffer against tragedy? Well, because when you lose an animal in a complex community, chances are good that something else will fill its role, said Sanders.
It's sort of impossible to control for variables in a large ecosystem like a river or a forest, so the scientists opted to study how extinction plays out in mesocosms, or miniature ecosystems. These consisted of bean and barley plants inhabited by several species of tiny insects called aphids. Aphids eat plants—technically, they suck sap—so they can represent a larger ecosystem's grazers, like deer. As for predators, the study included three parasitic wasp species, each of which preys on a specific type of aphid, as well as a fourth species of wasp that preys on any old aphid it can find.
Finally, because nature is a bit of a Russian nesting doll of horrors, there were also several species of wasps that prey on the wasps that prey on the aphids. These so-called hyperparasitoids, or parasites that prey on parasites, represent yet another level in the food chain, like jaguars that kill caimans.
Each community was set up on a table outdoors and surrounded by a 6.5-foot square of fine mesh that contained the creatures and prevented other insects from entering the mesocosm. At the same time, it allowed exposure to natural conditions like wind, rain and sunlight, just as the plants and insects would experience in the wild.
Field experiment with insect communities in mesocosms consisting of plants, aphids, and parasitoids.Dirk Sanders
To simulate extinction in half of the mesocosms, the scientists started squishing mummies. And that's when things got interesting. You see, these wasps don't prey on aphids by just killing and eating them. No, the wasps stab the aphid with a highly evolved syringe and then squirt an egg into its body. This egg hatches and begins eating the aphid alive. After the wasp larva has had its fill, it spins a cozy little cocoon around itself and begins to transform into an adult. Just like the Very Hungry Caterpillar turning into a butterfly―if that caterpillar were hanging out inside the corpse of an aphid.
The scientists sought out larvae from one parasitic wasp species, Aphidius megourae, and euthanized them with a pair of forceps. (To paraphrase T. S. Eliot, "This is the way the world ends. Not with a bang but a tweezer.")
A. megourae direct all of their destructive force against just one kind of aphid, Megoura viciae. So when this wasp was removed from the equation, its prey experienced a population explosion. After a few weeks, there were twice as many M. viciae in these mesocosms as in the control mesocosms in which no wasps were culled. That part was to be expected—get rid of wolves and mountain lions, and your deer population will go gangbusters.
What was less obvious was the way losing one species of wasp triggered the extinction of other wasp species. "This is similar to deer overpopulation," said Sanders. With so many new aphids of one species running around, the other aphid species got crowded out. And as it became harder to find those crowded-out aphids, the wasps that relied solely on them for food and a place to live began to decline until eventually they, too, went the way of the dodo.
The extinctions simulated in the lab indicated many more possible ecosystem impacts. For instance, more aphids of a certain species would likely lead to a decline of certain plants while others continue to thrive. That could affect pollinator species, the animals that eat pollinators, and so on and so on. Soil structure, microbial community, water quality—all of these variables also have the potential to change as a result of extinction cascades.
The thing is, Sanders and his colleagues found that mesocosms with more aphid and wasp species at the beginning of the experiment were less susceptible to these extinction cascades. This jibes with other studies, Sanders said, that have found that ecosystem functions, like decomposition and pollination, are dependent on maintaining a certain threshold number of species. Which makes sense—you can't expect a field full of flowers to mix genes without a ton of insects, or a carcass to disappear without the help of beetles, maggots, turkey vultures and an array of other organisms. "Therefore, in general the loss of biodiversity is a major concern, and extinction cascades can accelerate this loss," saic Sanders.
And that's a scary finding, given that scientists believe the earth is experiencing its sixth mass extinction, in which we are losing species at as much as 10,000 times the normal rate. Some species will surely be goners moving forward. However, if we can focus our conservation efforts on preserving as much biodiversity as possible, then we can give these ecosystems a chance to weather the storm.
Reposted with permission from our media associate onEarth.
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By Victoria Masterson
Using one of the world's problems to solve another is the philosophy behind a Norwegian start-up's mission to develop affordable housing from 100% recycled plastic.
Sustainable Homes<p>UN-Habitat says an <a href="https://unhabitat.org/un-habitat-aims-to-use-plastic-waste-to-support-housing-for-all" target="_blank">estimated 60% of people living in urban areas of Africa are in informal settlements</a>. At the same time, between 1990 and 2017, African countries imported around 230 metric tonnes of plastic, "which mostly ended up in dump sites creating a massive environmental challenge," the agency adds.</p><p>UN-Habitat deputy executive director, Victor Kisob, said the aim of the partnership with Othalo was to "promote adequate, sustainable and affordable housing for all."</p>
Artist's impression of an Othalo community, imagined by architect Julien De Smedt. Othalo<p>Othalo's process involves shredding plastic waste and mixing it with other elements, including non-flammable materials. Components are used to build up to four floors, with a home of 60 square metres using eight tons of recycled plastic. A factory with one production line can produce 2,800 housing units annually.</p><p>Following successful laboratory tests, Othalo's factory in Estonia has started producing components to build three demonstration homes for Kenya's capital, Nairobi; Yaoundé, the capital of Cameroon and Dakar, the capital of Senegal.</p><p>Othalo founder Frank Cato Lahti has been developing and testing the technology since 2016 in partnership with <a href="https://www.sintef.no/en/" target="_blank">SINTEF</a>, a 70-year-old independent research organization in Trondheim, Norway, and experts at Norway's <a href="https://en.uit.no/startsida" target="_blank" rel="noopener noreferrer">University of Tromsø</a>.</p>
Othalo founder Frank Cato Lahti. Othalo<p>Almost <a href="https://www.un.org/development/desa/publications/2018-revision-of-world-urbanization-prospects.html" target="_blank">seven out of every 10 people in the world are expected to live in urban areas by 2050</a>. More than 90% of this growth will take place in Africa, Asia, Latin America, and the Caribbean.</p><p>"In the absence of effective urban planning, the consequences of this rapid urbanization will be dramatic," UN-Habitat warns.</p><p>Lack of proper housing and growth of slums, inadequate and outdated infrastructure, escalating poverty and unemployment, and pollution and health issues, are just some of the effects.</p><p>Mindsets, policies, and approaches towards urbanization need to change for the growth of cities and urban areas to be turned into opportunities that will leave nobody behind, UN-Habitat says.</p>
Pioneers of Change<p>Reimagining cities and communities for greater resilience and sustainability was a key topic at the<a href="https://www.weforum.org/events/pioneers-of-change-summit-2020" target="_blank"> World Economic Forum's Pioneers of Change Summit 2020</a>.</p><p>The digital event brought together innovators and stakeholders from around the world to explore solutions to the challenges facing enterprises, governments and society.</p><p>Opening the summit, <a href="https://www.weforum.org/events/pioneers-of-change-summit-2020/sessions/opening-plenary-8f731cbc65" target="_blank">Stephan Mergenthaler, the Forum's Head of Strategic Intelligence and a member of the Executive Committee</a>, said: "We need to change the way we produce, the way we live and interact in our cities to make this transition to net-zero emissions a reality…</p><p>"And as this year has illustrated so dramatically, we need to make every effort that we keep populations healthy, if we want to avoid jeopardizing all this progress."</p><p><em>Reposted with permission from </em><em><a href="https://www.weforum.org/agenda/2020/11/un-africa-recycled-plastic-housing/" target="_blank">World Economic Forum</a>.</em><a href="https://www.ecowatch.com/r/entryeditor/2649069252#/" target="_self"></a></p>
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By Brett Wilkins
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By Dolf Gielen and Morgan Bazilian
John Kerry helped bring the world into the Paris climate agreement and expanded America's reputation as a climate leader. That reputation is now in tatters, and President-elect Joe Biden is asking Kerry to rebuild it again – this time as U.S. climate envoy.
Energy Is at the Center of the Climate Challenge<p>The <a href="https://science2017.globalchange.gov/chapter/1/" target="_blank">effects of climate change</a> are already evident across the globe, from <a href="https://theconversation.com/100-degrees-in-siberia-5-ways-the-extreme-arctic-heat-wave-follows-a-disturbing-pattern-141442" target="_blank">extreme heat waves</a> to <a href="https://science2017.globalchange.gov/chapter/12/" target="_blank">sea level rise</a>. But while the challenge is daunting, there is hope. Solar and wind power have become the <a href="https://www.irena.org/publications/2020/Jun/Renewable-Power-Costs-in-2019" target="_blank">cheapest forms of power generation globally</a>, and technology progress and innovation continue apace to support a transition to clean energy.</p><p>In the U.S. under a Biden administration, long-term national climate legislation will depend on who controls the Senate, and that won't be clear until after two run-off elections in Georgia in January.</p><p>But there is no shortage of <a href="https://www.bloomberg.com/features/2020-biden-climate-change-advice/" target="_blank">ideas for ways Biden</a> could still take action even if his proposals are blocked in Congress. For example, he could use executive orders and direct government agencies to tighten regulations on greenhouse gas emissions; increase research and development in clean energy technologies; and empower states to exceed national standards, <a href="https://www.reuters.com/article/us-autos-emissions-california/defying-trump-california-locks-in-vehicle-emission-deals-with-major-automakers-idUSKCN25D2CH" target="_blank" rel="noopener noreferrer">as California did in the past with auto emission standards</a>. A focus on a just and equitable transition for communities and people affected by the decline of fossil fuels will also be key to creating a sustainable transition.</p><p>The U.S. position as the world's largest oil and gas producer and consumer creates political challenges for any administration. U.S. forays into European energy security are often treated with suspicion. Recently, France blocked <a href="https://www.wsj.com/articles/frances-engie-backs-out-of-u-s-lng-deal-11604435609" target="_blank">a multi-billion dollar contract</a> to buy U.S. liquefied natural gas because of concerns about limited emissions regulations in Texas.</p><p>Strengthening cooperation and partnerships with like-minded countries will be critical to bring about a transition to cleaner energy as well as sustainability in agriculture, forestry, water and other sectors of the global economy.</p>
Creating a Global Sustainable Transition<p>How the world recovers from COVID-19's economic damage could help drive a lasting shift in the global energy mix.</p><p>Nearly one-third of Europe's US$2 trillion economic relief package <a href="https://www.bloomberg.com/news/articles/2020-07-21/eu-approves-biggest-green-stimulus-in-history-with-572-billion-plan" target="_blank" rel="noopener noreferrer">involves investments that are also good for the climate</a>. The European Union is also strengthening its 2030 climate targets, though each country's energy and climate plans will be critical for successfully implementing them. The <a href="https://joebiden.com/clean-energy/" target="_blank" rel="noopener noreferrer">Biden plan</a> – including a $2 trillion commitment to developing sustainable energy and infrastructure – is aligned with a global energy transition, but its implementation is also uncertain.</p><p>Once Biden takes office, Kerry will be joining ongoing <a href="https://www.un.org/en/conferences/energy2021/about#:%7E:text=The%20overarching%20goal%20of%20the,2030%20Agenda%20for%20Sustainable%20Development.&text=Accelerate%20delivery%20of%20United%20Nations,related%20issues%20at%20all%20levels." target="_blank" rel="noopener noreferrer">high-level discussions on the energy transition</a> at the U.N. General Assembly and other gatherings of international leaders. With the U.S. no longer obstructing work on climate issues, the G-7 and G-20 have more potential for progress on energy and climate.</p><p>Lots of technical details still need to be worked out, including international trade frameworks and standards that can help countries lower greenhouse gas emissions enough to keep global warming in check. <a href="https://www.carbonpricingleadership.org/what" target="_blank" rel="noopener noreferrer">Carbon pricing</a> and <a href="https://www.csis.org/analysis/how-can-europe-get-carbon-border-adjustment-right" target="_blank" rel="noopener noreferrer">carbon border adjustment taxes</a>, which create incentive for companies to reduce emissions, may be part of it. A consistent and comprehensive set of national energy transition plans will also be needed.</p><p>The global shift to <a href="https://www.irena.org/publications/2019/Jan/A-New-World-The-Geopolitics-of-the-Energy-Transformation" target="_blank">clean energy will also have geopolitical implications for countries and regions</a>, and this will have a profound impact on wider international relations. Kerry, with his experience as secretary of state in the Obama administration, and Biden's plan to make the climate envoy position part of the National Security Council, may help mend these relations. In doing so, the U.S. may again join the wider community of countries willing to lead.</p>
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By Maria Caffrey
As we approach the holidays I, like most people, have been reflecting on everything 2020 has given us (or taken away) while starting to look ahead to 2021.