Temple University biology professor S. Blair Hedges is part of a major study by more than 100 researchers that shows climate change is a major driver of amphibian declines globally. The paper was published in October in Nature, a major scientific journal. The study also found that salamanders are the most threatened group of amphibians, and that new emerging disease could devastate salamanders in the United States and Europe.
Habitat destruction and disease are both well-documented causes of the decline of amphibians—among the most threatened animals on the planet. However, this new paper, which analyzes two decades’ worth of data from around the world, concludes that climate change is emerging as one of the biggest threats to frogs, salamanders and caecilians (legless amphibians).
“This work demonstrates how another major group of organisms on Earth is declining because of human impact,” said Hedges, director of the Center for Biodiversity and a Laura H. Carnell Professor at Temple. "Our evidence shows that climate change is an emerging threat. Of course, these threats affect all organisms including us, so we need to deal with them soon.”
Hedges played a key role in this study—and the previous one in 2004—with his expertise on amphibians of the Caribbean islands, a region found in this analysis to have the most threatened species.
The study, “Ongoing declines for the world’s amphibians in the face of emerging threats,” is based on the second global amphibian assessment coordinated by the Amphibian Red List Authority, which is a branch of the International Union for Conservation of Nature’s Species Survival Commission’s Amphibian Specialist Group, hosted and managed by Re:wild.
The assessment evaluated the extinction risk of more than 8,000 amphibian species from all over the world, including 2,286 species evaluated for the first time. More than 1,000 experts across the globe contributed their data and expertise, which found that two out of every five amphibians are threatened with extinction.
According to the study, between 2004 and 2022, a few critical threats have pushed more than 300 amphibians closer to extinction. Climate change was the primary threat for 39% of these species. Climate change is especially concerning for amphibians because they are particularly sensitive to changes in their environment. Also, habitat destruction and degradation, disease and overexploitation are all threats that are exacerbated by the effects of climate change.
According to this new study, nearly 41% of all amphibian species that have been assessed are currently globally threatened, considered critically endangered, endangered or vulnerable—compared to 26.5% of mammals, 21.4% of reptiles and 12.9% of birds. Indeed, since the 2004 study, four amphibian species have been documented as going extinct and 27 additional critically endangered species are now considered possibly extinct. That brings the total to more than 160 critically endangered amphibians that are considered possibly extinct.
Conversely, the assessment also found that 120 species improved their Red List status since 1980; most did so as the direct result of conservation action.
“As humans drive changes in the climate and to habitats, amphibians are becoming climate captives, unable to move very far to escape the climate change-induced increase in frequency and intensity of extreme heat, wildfires, drought and hurricanes,” said Jennifer Luedtke Swandby, Re:wild manager of species partnerships, Red List Authority coordinator of the IUCN SSC Amphibian Specialist Group and one of the lead authors of the study. “Protecting and restoring forests is critical not only to safeguarding biodiversity, but also in tackling climate change.”
Conservationists will use the information from this study to help inform a global conservation action plan, to prioritize conservation actions at the global level, to seek additional resources and to influence policy that can help reverse the negative trend for amphibians.