Extinction is part of the history of life, with individual species continually disappearing from the fossil record. But during a mass extinction, the Earth loses much of its biodiversity in a short period of time. Over the past 400 years, a large number of species of mammals, birds, amphibians and reptiles have become extinct due to human hunting or destruction of their natural habitat. But this may only be the beginning.
Using one of the most powerful supercomputers in Europe, European Commission scientists Dr. Giovanni Strona of the University of Helsinki and Professor Corey Bradshaw of Flinders University used computer models to create a virtual globe containing artificial species and over 15,000 food webs to predict the interconnected fates of species that are likely to disappear due to disruptive changes in climate and land use in the next century.
The model makes bleak predictions about the future of global diversity, confirming undeniably that the world is headed for a sixth mass extinction.
Both scientists say that past methods for estimating extinction rates in the coming century have been underestimated because they do not take into account co-extinction, that is, the extinction of species as other species on which they depend succumb to climate and/or landscape change. changes.
“Think of a predatory species that is losing its prey to climate change. The extinction of a prey species is “primary extinction” because it succumbs directly to disturbance. ‘). Or imagine a parasite losing a host due to deforestation, or a flowering plant losing a pollinator due to too much heat. Each species depends on the other in some way,” Bradshaw explained.
Until now, researchers have not been able to match species to each other on a global scale to estimate how much additional loss a co-extinction would cause. While there are many excellent analyzes examining various aspects of extinction, such as the direct impact of climate change and habitat loss on the fate of species, these aspects do not necessarily combine realistically to predict the extent of extinction cascades.
Strana and Bradshaw’s solution to this problem is to build a giant virtual globe made up of interconnected networks of species connected by who eats whom, and then apply it to a climate change and land use system to inform future predictions and provide information.
As the climate changes, virtual species may also re-colonize new areas, may adapt to changing conditions to some extent, may become extinct as a direct result of global changes, or may fall victim to a cascading extinction event.
“Basically, we built a virtual world from the ground up and mapped the ultimate fate of thousands of species around the world to determine the likelihood of tipping points in the real world,” Strona explained.
“By running several simulations of the three main IPCC climate scenarios up to 2050 and 2100, we show that by 2100 the total number of joint extinctions will be 34% higher than predicted based on direct effects alone,” Strona said.
“This study is unique in that it also looks at secondary impacts on biodiversity, assessing the impact of species extinction in local food webs beyond the direct impact. The results show that interconnections within food webs exacerbate biodiversity loss,” added Bradshaw.
“Compared to traditional methods of predicting extinction, our model provides a detailed view of changes in patterns of species diversity where climate, land use and ecological interactions interact. A child born today at age 70 can expect more species to disappear. Thousands of plant and animal species, from tiny orchids and tiny insects to iconic animals like elephants and koalas… all in one lifetime.”
Amphibians are among the most endangered animals, according to a United Nations summary report released in 2019, with 40 percent of the species studied being threatened, followed by plants at 34 percent, coral reefs at 33 percent, and cartilaginous fish such as sharks and rays. 31.%, invertebrates such as insects accounted for 27%, mammals 25%, and birds 14%.
Professor Bradshaw said that while it is now widely believed that climate change is the main cause of global extinction, the new analysis clearly shows that we have so far underestimated its true impact on the diversity of life on Earth. Without major changes in human society, we will lose much of what sustains life on Earth.
The journal Science Advances (2022) published a study “The joint extinction of vertebrates in the future will prevail over the losses of vertebrates due to climate and land use changes.” Materials provided by Flinders University.
Post time: Dec-21-2022