Amphibian species in global decline

Frogs and other amphibians are rapidly becoming extinct around the world and in Latin American countries in particular. In the Caribbean, as many as 80 percent of these species are endangered, while in Colombia 209 and in Mexico 198 species of amphibians may soon disappear. Environmental degradation, habitat loss, ultraviolet radiation, disease and climate change are all factors involved in these unprecedented losses. At least 43 percent of amphibians are in decline worldwide. An estimated 170 frogs, toads and salamanders may already have become extinct in the past two decades. "Amphibians are telling us that there is something wrong with our ecosystems," says Robin Moore, amphibian conservation officer with Conservation International (CI), a US-based international non-governmental organization. Amphibians have very porous skins, which seems to make them more vulnerable to environmental changes than mammals, birds and reptiles. Some scientists consider them as bellwether animals for the Earth's health. According to the Global Amphibian Assessment, which examined the status of the nearly 6,000 known amphibians, the highest levels of threat are found in the Caribbean, where more than 80 percent are threatened in the Dominican Republic, Cuba and Jamaica, and a staggering 92 percent in Haiti. "There are huge numbers of amphibians that we don't even know about yet," Moore said. Completed in 2004, the assessment was the biggest effort ever to determine the status of amphibians. Despite this effort, regions like Latin America may have two or three times more unidentified species of amphibians than scientifically recognized species, he said. Amphibians are important in many ecosystems, particularly in tropical zones, where they are so numerous they play an important role in controlling insects and bugs that can cause diseases in people. Last year, scientists and conservation groups called for the creation of an Amphibian Survival Alliance, a global network to halt the decline before hundreds more of these species go extinct. The $400 million, five-year effort for research, field programs, captive breeding and habitat protection has yet to get off the ground. The Alliance, coordinated by CI and the amphibian specialist group of the World Conservation Union, hopes to hire a full time executive director in the next few weeks, Moore said. Amphibian experts met recently in Atlanta, and issued a call to the world's zoos, aquariums and botanical gardens to create an Amphibian Ark. They are asking institutions to take in at least 500 frogs from a threatened species to protect them from chytrid fungus. Each frog would be cleaned to make sure it doesn't introduce the scourge into the protected area. The decline of amphibians is a far bigger problem than a nasty fungus, says Alan Pounds, the resident ecologist at the Tropical Science Center, located in the Monteverde Cloud Forest Preserve in Costa Rica. "There is no strong evidence for the fungus being the only reason," Pounds said. Pounds' own research shows that climate change is disrupting the ecology of the misty mountainsides in Central and South America and precipitated a decline in the brightly colored harlequin frogs. Two thirds of the more than 100 species of harlequin frogs have vanished since the 1980s. Warming temperatures have enhanced cloud cover on mountainsides, leading to cooler days and warmer nights, both of which increase the viability of the chytrid fungus. Climate change appears to have created more favorable conditions for the spread of the fungus, he said. Frogs are also sensitive to pesticides, poor water quality, acid rain and other environmental contaminants. Add in climate change, which is altering complex ecological processes including disease dynamics, and there will be subtle and sometimes significant impacts on species. "It seems surprising and shocking that species disappear from seemingly untouched nature preserves. But there is no place on the planet that is untouched," Pounds said. The global scope and variety of environmental changes make it extremely difficult for science to determine exactly why all members of one frog species die out after living on the Earth for a million years. There must be better habitat management, including understanding what is happening in ecosystems, as well as urgent action on environmental deterioration and climate change to slow the loss of amphibian and other species, Pounds said. "We should be listening to the message from the frogs. They are warning us about environmental deterioration that threatens all species and our own well being," he said.