An Article, an Audio CD Set, and a best selling Book by Elizabeth Kolbert

Scientific Article by Giavonni Strona & Corey Bradshaw, Science Magazine, Dec. 16, 2022

ABSTRACT ~ Although theory identifies coextinctions as a main driver of biodiversity loss, their role at the planetary scale has yet to be estimated. We subjected a global model of interconnected terrestrial vertebrate food webs to future (2020–2100) climate and land-use changes. We predict a 17.6% (± 0.16% SE) average reduction of local vertebrate diversity globally by 2100, with coextinctions increasing the effect of primary extinctions by 184.2% (± 10.9% SE) on average under an intermediate emissions scenario. Communities will lose up to a half of ecological interactions, thus reducing trophic complexity, network connectance, and community resilience. The model reveals that the extreme toll of global change for vertebrate diversity might be of secondary importance compared to the damages to ecological network structure.

INTRODUCTION ~ The planet has entered the sixth mass extinction (1–5). There are multiple causes underlying the rapid increase in observed and modeled extinction rates in recent times, of which land-use change, overharvesting, pollution, climate change, and biological invasions figure as dominant processes (6). However, assessing the relative importance and the realistic impact of such drivers at the global scale remains a challenge. Another aspect rendering assessment difficult are the synergies between drivers — a species might go extinct for multiple, simultaneous reasons, and in such contexts, ecological interactions play a fundamental role in predicting its fate (7). Growing recognition of the importance of species interactions in promoting the emergence of biodiversity in complex natural communities implies that an additional, fundamental component of biodiversity loss is represented by the amplification of primary extinctions across ecological networks. Coextinction — the loss of species caused by direct or indirect effects stemming from other extinctions — is now recognized as a major contributor to global biodiversity loss, strongly amplifying the effect of primary (e.g., climate-driven) extinctions (8–11).

Networks of ecological interactions are central to global patterns of diversity loss not only because coextinctions can be triggered by other extinction drivers, but also because network structure and dynamics might modulate several processes that can either reduce or increase extinction rate. For example, it is intuitive that a species’ success in colonizing a new area depends strongly on its ability to exploit local resources while simultaneously escaping enemies (predators and parasites). The addition of the new species might also initiate substantial changes to and have important cascading effects in the local network. Ignoring the structure of ecological networks and how they reconfigure as their constituent diversity changes therefore gives a possibly misleading view of the future of global diversity.

Previous attempts to predict the future of global diversity in the face of climate change and habitat modification have only considered the direct effects of these drivers on species (typically on single taxonomic groups), without explicitly accounting for ecological interactions. For instance, Thomas et al. (12) used projections of species’ distributions and species-area relationships to predict extinction rates for 20% of Earth’s surface, and Malcolm et al. (13) applied both species-area and endemic-area relationships to predictions of biome shift under climate change in Biodiversity Hotspots. van Vuuren et al. (14) also applied species-area relationships to vascular plants to project extinctions under different land-use and climate-change scenarios within the Millennium Ecosystem Assessment, and Jetz et al. (15) used a similar approach for birds. Others have applied analogous techniques to many other taxa, including lizards (16), crop wild relatives (17), chelonians (18), bird, amphibians, and corals (19). Later, Warren et al. (20) applied point-process and global circulation models to predict climate change–induced shifts in species’ distributions, and Urban (21) did a meta-analysis (including many of the studies cited above) to predict extinction rates of various taxa under several climate-change scenarios. Despite this extensive research foundation, future inferences of biodiversity’s fate over the coming century are likely to underestimate extinctions arising from global change (11).

Apart from the obvious modeling and computational challenges to incorporate interactions among species, the main reason why there are few studies accounting for interactions is that obtaining sufficient data in most communities is intractable. Therefore, global-scale modeling of entire ecosystems appears to be the only viable solution, even if a challenging one (11, 22). Recent developments in network approaches have shown that potential ecological interactions can be derived by applying different techniques (e.g., machine learning) to available datasets on species distribution and ecology (23, 24). In previous work (11), we built on that idea to generate global-scale models of biodiversity by including species interactions using virtual species constructed to follow real-world archetypes. In such synthetic approaches, a virtual species is a plausible ecological entity that has a combination of ecological traits consistent with real-world species despite not corresponding exactly to them.

There are several advantages in using virtual species in this manner. The first is that once the rules have been set to generate virtual species, current gaps and biases in biodiversity sampling cease to be a limitation; we can use virtual species to populate the entire Earth and generate plausible ecological communities, even in areas where data on local diversity are scarce or missing. Second, virtual species avoid preconceptions (and biases) about current biodiversity patterns, permitting instead a focus on the processes involved in change. Here, we can populate an entire virtual planet with species, let them develop communities based on a modest set of realistic ecological rules and assumptions, and then explore the emerging patterns. With such an approach, real-world data serve as a template for generating the virtual species and for identifying the basic ecological rules controlling community dynamics and as a benchmark with which to validate the realism of modeled predictions.

We previously demonstrated how coextinctions increase the pace of annihilation of life on Earth by up to 10 times relative to primary extinctions, but only in the face of catastrophic, no-return environmental change modeled as either extreme planetary heating or cooling (11). Although an instructive proof of concept, that model contained many simplifications and was applied to (hopefully) unrealistic scenarios of global change. Building on that original approach, here we developed a more complex, and ecologically realistic dynamic model to represent all terrestrial vertebrate communities with which we project future biodiversity trends. By accounting for both primary extinctions and their resulting coextinctions, the model predicts the cumulative toll on global biodiversity of different climate and land-use change projections up to 2100 at a spatial scale of 1° × 1° and at a monthly temporal resolution. In addition to providing estimates of potential global diversity loss, the model quantifies the relative contribution of the different extinction drivers at the global scale for the first time.

This Article continues in Science Magazine.

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See also: The Sixth Extinction? | Elizabeth Kolbert, The New Yorker Magazine, May 18, 2009

Scientist Emma Smart arrested on April 13th in London

From an Article by Jake Johnson, Common Dreams, April 15, 2022

Scientist Emma Smart went on a hunger strike Thursday after she was denied bail by London authorities while awaiting a court hearing on charges of “criminal damage,” which were filed after Smart and others glued scientific papers and themselves to a U.K. government building to protest destructive climate policies.

Smart, an ecologist, was arrested alongside fellow scientists earlier this week as they took part in a global nonviolent mobilization aimed at pressuring world leaders to stop expanding fossil fuel production in the face of intensifying climate chaos.

The U.S. National Oceanic and Atmospheric Administration (NOAA) released new research Thursday ranking last month as Earth’s fifth-warmest March in 143 years and warning that Antarctic sea ice coverage has shrunk to a “near-record low.”

According to a series of tweets posted to Smart’s personal Twitter account, “she has been held in a permanently lit single cell with no window for over 40 hours” while her allies with Scientists for Extinction Rebellion were released on bail. Smart has been refusing both food and water since Thursday morning.

Smart’s court hearing is set for Saturday, Extinction Rebellion said in a press release. Showing solidarity with Smart and protesting her detention, scientists gathered Friday for a vigil on the steps of Charing Cross Police Station in London, where she’s being held, as youth climate strikers held their weekly demonstrations around the world.

Andy Smith, Smart’s husband, said in a statement Friday that “this was a minor crime with no disruption to the public.”

“Her treatment is disproportionate to her crime,” Smith continued. “What kind of world do we live in when scientists are forced to put themselves into positions of arrest and hunger strike to be heard? And why has she not been released?”

“Emma knows what’s at stake if we don’t stop fossil fuel investments and she is taking a stand for her nieces’ future and all those around the world suffering now from this crisis. Everyone must stand with her now and come out on the streets to show the government that change is coming whether they like it or not.”

Smart is one of dozens of scientists who have been arrested across the globe in recent days as climate experts—dismayed by governments’ continued refusal to heed their warnings—turn to direct action.

“The fact that Emma is being held beyond the usual 24 hours shows that the U.K. government is effectively at war with climate science,” said Pete Knapp, an air-quality scientist with Scientists for Extinction Rebellion. “They would rather lock up and silence experts sounding the alarm than do their duty and protect the public from catastrophic climate change.”

“The science is totally clear: we must not drill for new oil and gas,” said Knapp. “Instead we must move to clean energy as quickly as possible. But our government only last week declared it will license new fossil fuel exploration in spite of repeated and dire warnings from scientists that this will lead to disaster. This is the flagrant dereliction of duty that Emma is calling out, and they are locking her up for it.”

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Former ecologist Emma Smart talks to Emma Wrake AMRSB about her recent arrest at an Extinction Rebellion protest, and why more and more scientists are joining the activist group

From the Royal Society of Biology, London, April 15, 2022

Earlier this month, Emma Smart became the latest member of ‘XR Scientists’ (a group of scientists and former scientists within the Extinction Rebellion Activist movement) to be arrested. Footage shows her attempting to give a speech outside the Department of Health in London about the impact of animal agriculture on ecosystems and public health, before being surrounded by police. After refusing to move her protest to Parliament Square, she was then lead away and arrested, and police confiscated her speech, loudspeaker and microphone.

Smart, who spent nine years working to conserve freshwater species in the Middle East and discovered a new species of Arabian freshwater fish (Garra Smarti), says she became disillusioned with what she could achieve in conservation through research and NGOs, and has been an activist for the past year.

The XR Scientists group now has over 250 active members, some of whom were featured in a Biologist article on science and activism in June. Smart is currently challenging her arrest and says the police are using powers to thwart protests and ‘gag’ scientists from speaking at protests. “I once believed the people making decisions would listen to scientists – that is not true”

Deforestoration research underway

From an Article by Chris Mooney, Washington Post, July 14, 2016

Photo in original article: An aerial view shows a tract of Amazon rain forest that has been cleared by loggers and farmers for agriculture near the city of Santarem, Para State, April 20, 2013.

In an ambitious study that represents the latest merger between big data approaches and the quest to conserve the planet, scientists have found that across a majority of the Earth’s land surface — including some of its most important types of terrain and its most populous regions — the abundance or overall number of animals and plants of different species has fallen below a “safe” level identified by biologists.

The reason is not exactly a surprise — from grasslands to tropical forests, humans are using more and more land for agriculture, to live on, to build roads and infrastructure upon. When we take over, we clear the land or otherwise convert it for our purposes. This doesn’t always cause extinctions, but it does reduce the abundance of species and what researchers call the “intactness” of ecosystems — and when biodiversity levels fall too low, it can mean that larger ecosystems lose their resilience or even, at the extreme, cease to function.

“Exploitation of terrestrial systems has been vital for human development throughout history, but the cost to biosphere integrity has been high,” notes the study published Thursday in Science, which was led by Tim Newbold of the United Nations Environment Programme and University College London with a large group of colleagues representing several British, Australian, Danish and Swiss universities and institutions.

The researchers compiled 1.8 million separate measurements of the abundance of species (39,123 of them) at 18,659 locations across the globe — a volume of data that an accompanying essay in Science, by ecologist Tom Oliver of the University of Reading, calls the “most comprehensive quantification of global biodiversity change to date.”

The researchers then extrapolated across the rest of the planet, and compared the results to a “Biodiversity Intactness Index” to determine where species declines were too great.

The research is based on a “planetary boundaries” concept that “attempts to set some sort of safe limit to the amount of biodiversity we can lose, while biodiversity still supports important ecosystem functions,” said Newbold, the study’s lead author. And it is important to note that in the context of this analysis, safety actually means safe for humans, in significant part.

The concern is that species-anemic ecosystems will struggle or fail, and so become unable to provide us what we actually need in the form of stored carbon, filtered water, fertile soils and much else. Animals need these ecosystem “services,” to be sure, but so do humans.

“Biodiversity supports a number of functions within ecosystems, things like pollination, nutrient cycling, soil erosion control, maintenance of water quality,” Newbold said. “And there’s evidence that if you lose biodiversity, that these functions don’t happen as well as they would have done in the past.”

As a conservative or precautionary standard, the researchers therefore assumed that a decline of more than 10 percent of species abundance in a given area (compared with what that abundance was before human interference) represented crossing into a danger zone for biodiversity. But their study found that overall, across the globe, the average decline is already more like 15 percent. In other words, original species are only about 85 percent as abundant (84.6 percent to be precise) as they were before human land-use changes.

Some places are, of course, better off than others — for instance, northern tundras and boreal forest ecosystems were still relatively intact, the study found. So was much of the Amazon rain forest. In contrast, central North America showed a huge gash on the researchers’ maps, representing a large region with less than 60 percent of its original biodiversity intact, stretching all the way from Canada to Texas.

Overall, 58 percent of the Earth had declined below 90 percent biodiversity intactness and, in effect, into the danger zone. And this was strongly correlated with human population — that 58 percent of the Earth is the home to 71 percent of its human inhabitants, the study reported.

There are, to be sure, some major uncertainties (and matters of interpretation) in this analysis, ones that the authors freely acknowledge. For instance: Who is to say that 90 percent “intactness,” or abundance of the original species that lived in an ecosystem, is the right number in all cases?

And moreover, it isn’t just that ecosystems have been losing original species — they have also been gaining, in many cases, non-original or “invasive” species. So is that a net plus to them, or a net minus?

The study considered these options and, not surprisingly, found that if new species are considered to benefit ecosystems, or if ecosystems can go down to 80 or 70 percent of their original species abundance, then considerably less of the world is in trouble. In the end, then, this really boils down to a decision about how much risk you want to take with nature.

It is not, therefore, that ecosystems are about to start collapsing all around us because of passing this 90 percent threshold. However, the research does mean that less-intact ecosystems will be less able to withstand future challenges like ongoing global warming, Newbold said.

“We’re entering a space where things become more uncertain, and we expect that things will be less resilient in the face of other changes,” he said.

Immediate reactions to the work were mixed from two experts consulted by the Post to respond to the study.

“Newbold and colleagues find sobering evidence that we have already crossed that line in terrestrial ecosystems,” said Mark Urban, who directs a newly founded Institute of Biological Risk at the University of Connecticut, which focuses on biodiversity losses. “Human land use has reduced local populations to 85 percent of original abundances on average. What this means is we have not only crossed a planetary boundary, but have kept going. At least now we’re looking back.”

Urban added that while the new study stresses the impact of changes in land use, “this result ignores the accelerating threat from a warming climate. Climate change is about to make things more complicated as we try to pull back from the edge of the Earth’s resilience.”

But Erle Ellis, who directs the Laboratory for Anthropogenic Landscape Ecology at the University of Maryland, Baltimore County, had a different take. While Ellis said the new study “should be widely read and thought about,” he challenged the basis for the 90 percent figure used in the paper, suggesting the threshold was “arbitrary.”

“There is no rigorous scientific basis behind the concept that there is a single measurable ‘safe space’ for biodiversity change,” Ellis said by email.

“As a policy message, with numbers and maps of how much and where ‘safe limits’ on biodiversity change are exceeded, this paper goes way beyond the science — and this could lead to very faulty decisions on strategies and priorities for conservation,” he added.

There is no dispute, then, that humans have caused a significant retraction of non-human biological life on land — that they have, in effect, acted very effectively as its competition. Nor is there much dispute that human-caused climate change will act on top of this preexisting disturbance as an exacerbating factor.

The question, then, remains how close we are to a point where global ecosystems could see major tipping points, or dramatic changes of a sort ultimately traceable to us.

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How Thomas Lovejoy’s new research could link deforestation to climate change

Video in original article:  1:48 minutes

Deforestation may be leading to climate change in more ways than we know.