Losing Frogs

“Amphibians [including frogs and toads] are the most threatened group of vertebrates on the planet,” says Pieter Johnson, Ph.D., assistant professor of ecology and evolutionary biology at the University of Colorado, Boulder. Between 30% and 40% of amphibian species are declining, with nearly 200 species believed to have gone extinct since the 1970s, says Johnson. Infections such as the chytrid fungus “can cause whole populations and species of frogs to die off,” Johnson says.

Sometimes scientists take stop-gap measures. “If you can’t mitigate what’s going on in the wild and it looks like a population will disappear, we set up a survival assurance population, moving a number of the threatened frogs into captivity to breed them with the hope to return them into the wild,” says Allan Pessier, Ph.D., senior scientist at the Institute for Conservation Research.

Modern society and frogs have been at odds for some time. Frogs lose habitats to housing complexes, parking lots and industrial growth. And atrazine, an herbicide, is an endocrine disrupter that feminizes male frogs, limiting their ability to reproduce in the wild. Recreational fishing can impact frogs, too. For example, the California Department of Fish and Game stocked lakes with trout that ate tadpoles, decreasing the number of frogs

Since their thin skins are susceptible to contaminants, frogs also serve as early warning signals. “Amphibians play an important role in food webs and ecosystems, functioning as food for many larger vertebrates such as birds, snakes and mammals while also acting as predators on many insect pests,” says Johnson. Frogs have glands in their skin and release powerful chemicals that may also lead to treatments for HIV, the AIDS virus and cancer

So what can we do? Support conversation groups such as Amphibian Ark. Take an activist role. Kerry Kriger, Ph.D., executive director of Save the Frogs, recently staged a protest against the city-owned Sharp Park Golf Course in San Francisco. Kriger says the golf course, located on coastal wetland, is drained each year by San Francisco to create dry land for golf, killing the endangered California red-legged frogs when their egg masses get stranded on land during the pumping operations.