Two in five amphibian species are at risk of extinction, and their threats are increasingly coming from climate change, according to a new study published Wednesday in the journal Nature.
A large team of researchers from across the world analyzed the conservation status of amphibians based on the International Union for Conservation of Nature (IUCN) Red List of Threatened Species, which categorizes animals by the degree of extinction risk they face. For species that have been elevated into a higher risk category since 2004, climate change was the most common driver of their reclassification, the assessment found.
“It’s a gut punch and an awakening,” JJ Apodaca, the executive director of the nonprofit Amphibian and Reptile Conservancy who did not contribute to the findings, tells the Washington Post’s Dino Grandoni.
Notably, the report is not all gloom and doom. Some species have improved from their 1980 threat statuses and conservation efforts have helped, though on the whole, amphibians experienced more status declines (788) than improvements (120) since then.
Amphibians are cold-blooded vertebrates such as frogs, toads, newts and salamanders. Their cold-bloodedness makes them particularly vulnerable to climate change, because it leaves them sensitive to shifts in temperature and the environment, writes USA Today’s Doyle Rice.
“They don’t have any protection in their skin,” Patricia Burrowes, a biologist at the University of Puerto Rico, tells NPR’s Nathan Rott. “They don’t have feathers, they don’t have hair, they don’t have scales.”
Our experts suggest that amphibians continue to be the most threatened vertebrates globally with 2 out of 5 species threatened with extinction.— IUCN SCC Amphibian Specialist Group (@ASG_IUCN) October 5, 2023
The new study catalogs the risks facing 8,011 amphibian species and is the second report of its kind, following the Global Amphibian Assessment of 2004. The researchers found that 2,873 of these species—40.7 percent of those studied—are either critically endangered, endangered or vulnerable, a small increase from 37.9 percent of observed species in 1980 and 39.4 percent in 2004.
These findings make amphibians the vertebrate group with the greatest proportion of threatened species, ahead of mammals (26.5 percent), reptiles (21.4 percent) and birds (12.9 percent). Since 2004, four amphibian species have been deemed extinct, and 23 have been added to the list of possibly extinct creatures.
Researchers say the highest concentrations of threatened amphibians are in the Caribbean islands, Mesoamerica, the Tropical Andes region, western Cameroon, eastern Nigeria, Madagascar, Sri Lanka and the Western Ghats mountain range in India.
Types of habitat loss and degradation are among the most common hazards to the animals, with agriculture affecting 77 percent of threatened amphibians, harvest of timber and plant impacting 53 percent and infrastructure development disturbing 40 percent. Climate change affects 29 percent of threatened species, as does disease.
But in recent years, climate change has been playing a bigger role in driving amphibians to a more at-risk status. Among species that saw their Red List status worsen between 1980 and 2004, disease was the primary driver for 58 percent, while climate change was the primary driver for only 1 percent. But between 2004 and 2022, that proportion rose to 39 percent for climate change and fell to 23 percent for disease, making human-caused warming the most common primary driver of a status demotion currently.
“It’s very worrying,” Ana Rodrigues, a conservation ecologist at the Center for Functional and Evolutionary Ecology in France who was involved in the 2004 report but not the most recent one, tells Science News. “We’re at the beginning of climate change … What’s ahead of us?”
“There is a growing proportion of species being pushed to the brink of extinction by disease and the effects of climate change,” Luedtke tells the Washington Post. “So, habitat protection alone just won’t be sufficient as a risk-reduction measure.”
Among the solemn news, the study did have a bright spot: Conservation efforts have led to the improvement in risk status for 63 of the 120 species that have attained a more favorable status since the 1980s. Other species have improved after recovering from the impacts of a fungal disease which decimated amphibians across the globe.
The findings show that conservation efforts can be effective, and by gathering more information about the risks facing amphibians, scientists can better target such actions.
“Amphibians are disappearing faster than we can study them, but the list of reasons to protect them is long, including their role in medicine, pest control, alerting us to environmental conditions, and making the planet more beautiful,” Kelsey Neam, a co-author of the study who works for the environmental group Re:wild, tells USA Today.