Amphibians are the world’s most vulnerable animals, with about 41 percent of all species across the planet threatened with extinction, according to a new global assessment. This number has risen about three percent from 1980 and two percent from the last assessment in 2004, largely thanks to habitat loss, climate change and disease.
"It's a gut punch," JJ Apodaca, head of the nonprofit group Amphibian and Reptile Conservancy, who was not involved with the new research, tells Nathan Rott of NPR. "Here we are 19 years later with things not only not improved but getting worse."
Researchers analyzed more than two decades’ worth of data on 8,000 species, or about 93 percent of all described amphibians. They discovered that 2,873 met International Union for Conservation of Nature criteria for classification as critically endangered, endangered or vulnerable. Of all the amphibians surveyed, salamanders and newts were the most threatened, the authors discovered. They published their results in the journal Nature.
Amphibians are a class of cold-blooded vertebrates that include frogs, toads, salamanders and newts. They live on all continents across the globe except for Antarctica and have porous eggs and semi-permeable, moist skin. These animals get their name from the Greek word amphi, which means "dual," and bio, meaning "life." “Dual life” refers to the two life stages of most amphibians—one stage in the water as young and another on land as adults. Because many amphibians require two distinct environments during their lifetime, they can be disrupted when either habitat changes, University of Texas biologist Michael Ryan, who was not involved in the study, tells Christina Larson of the Associated Press.
“We know amphibians are particularly sensitive to changes in their environment, in part because they breathe through their skin,” lead author of the paper, Kelsey Neam, a species and metrics coordinator for the non-governmental organization Re:wild, said at a news conference, writes Evan Bush for NBC News. “The effects of climate change, including the increasing frequency and intensity of extreme weather events—such as storms and floods and droughts, changes in moisture, changes in temperatures, sea level rise, fires—all of these things can result in loss of important breeding sites for amphibians.”
Strikingly, the assessment suggests climate change effects were the primary drivers that pushed 119 species (39 percent) closer to extinction between 2004 to 2022. This is compared to only six species (1 percent) between 1980 and 2004. The authors write that these findings are “of particular concern” because climate change often exacerbates other threats like land-use change, fire and disease.
Over the past half century, an infectious fungal disease called chytridiomycosis has been particularly deadly for amphibians, wiping out roughly 90 species and leading to the decline of another 400. Some researchers have hypothesized that climate change has made amphibians more susceptible to the fungus.
Amphibians are a critical part of the food web, because they eat up insect pests like mosquitoes and serve as a food source for larger predators. Yet, these vertebrates are often overlooked compared to groups like birds or mammals, Neam tells Dino Grandoni of the Washington Post. About a fourth of mammals are threatened with extinction and about an eighth of birds, per the publication.
The new study is a “big update on the conservation of amphibians across the globe,” Adam Leaché, a biologist at the University of Washington and a curator at the Burke Museum of Natural History and Culture in Seattle, tells NBC News. “In general, I think the patterns we see globally reflect what a lot of us think is happening locally, as well.”