A lot can happen in tens of thousands of years.
In fact, virtually all of human history is confined to that time span. Since people began to dot the planet roughly 100,000 years ago, numerous animals have evolved and disappeared, often at extremely slow rates. Fossil records suggest that just one species
out of every million goes extinct each year. Throughout most of human history, extinctions were so unusual they went almost entirely unnoticed.
So it came as stunning news when scientists recently announced that amphibian extinctions that ordinarily occurred over tens of thousands of years have happened in the blink of an eye. As many as 122 species may have died out since 1980 alone. Amphibians – the first terrestrial vertebrates to grace the planet – are now in the midst of a catastrophic decline. One third of all amphibian species are now threatened with extinction.
This new finding is the result of a three-year study called the Global Amphibian Assessment. It is the most comprehensive analysis of its kind ever conducted and represents the efforts of 500 researchers from more than 60 countries. Scientists from the Center for Applied Biodiversity Science at CI, working in partnership with two other environmental groups, assessed all 5,743 known amphibian species.
The decline of the amphibians is largely about frogs, toads, and other aquatic, air-breathing creatures. But it’s also about us. Like the proverbial “canary in the coalmine” that dies at the first whiff of poison, amphibians are one of nature’s best indicators of overall environmental health. Their highly permeable skins respond more quickly than other creatures to increased pollution levels in air and fresh water. The startling amphibian losses are nothing but bad news for other forms of life – including us.
IUCN herpetologist Simon Stuart who led the assessment puts it plainly. “Their rapid decline tells us that one of Earth’s most critical life support systems is breaking down,” he says.
In some places, the numbers are staggering. In Haiti, 46 out of 50 species are threatened with extinction and more than 80 percent in the Dominican Republic, Jamaica, and Cuba face similar peril. And although the picture is less bleak in the United States, at least 51 species are threatened there.
In some parts of the world, primarily the Americas, the Caribbean, and Australia, a disease called chytridiomycosis is wiping out amphibians in large numbers. There is currently no known cure for this fungal disease. Scientists believe it is worse in drought years and may be exacerbated by climate change because dry skin makes amphibians more vulnerable to infection.
In other parts of the world, including Europe, Asia, and Africa, other threats such as habitat destruction, air and water pollution, and the marketplace are the leading causes of amphibian decline. In China, for example, vast numbers of giant salamanders (Andrias davidianus) and other amphibians are considered a delicacy.
It doesn’t take great forecasting skills to predict that the alarming trend will get worse before it gets better. Still, there are grounds for optimism. From this new research, we know with more precision where conservation dollars should be spent for the greatest effect. Increased funding for captive breeding programs will help, and new forest and wetland reserves in carefully selected areas can also make a big difference.
“Although we can’t reverse extinctions,” says CI’s Claude Gascon, “the good news is that it’s not too late to save many of the most threatened amphibians – if we take action now.”