The Status of the World's Amphibians

New research shows population declines in many of the world's amphibian species.

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The The Global Amphibian Assessment (GAA), originally published in 2004, was a first of its kind report. Until then, lack of an adequate data base hampered scientists attempting to understand trends in amphibian populations around the world.

As of June 2007, the GAA lists a total of 5,918 amphibian species in the world. Frogs and toads lead the list with 88% or 5, 211 different species. Of those, 1,590 or 30.5% were listed as either vulnerable, endangered or critically endangered.

Salamanders and newts account for the second largest number of amphibian species with 535 or approximately 9% of the total. Of those, 249 or 46.5% were listed as either vulnerable, endangered or critically endangered.

Caecilians round out the list with 172 or a bit over 2% of the total. Of those, 5 or 2.9% were listed as either vulnerable, endangered or critically endangered.

The list is far from complete with little or no data on amphibian species entered for some states such as the Democratic Republic of Congo. Forthcoming data from other states such as Indian, Indonesia and Malaysia is anticipated to add to and alter the aggregate results. Therefore, current statistics need to be read as a first take comparative examination of global amphibian population trends.

Various reasons are given for population declines, with habitat loss cited as the primary causal factor. Amphibian population levels are exacerbated by two inter-related geographical factors. First amphibians are tied to both a specific geographical location and a specific habitat. Close to 90% of the world's amphibians live in a forest habitat. Global deforestation trends in the past couple of decades has contributed to declining amphibian populations.

Additionally, many amphibians are endemic or limited to one state. In combination, five states, Brazil (489), Colombia (337). Mexico (246), Madagascar (225) and Australia (200) have a total of 1,497 different endemic species, 25.3% of the global total. Endemism limits any one size fits all solution to the problem. In the aggregate, the statistics can only suggest that improved forest and water management in states around the world will generally aid amphibian populations.

Over the next couple of years, scientists are promoting a four part Amphibian Conservation Action Plan in order to more effectively deal with global amphibian population decline.

• Expanded understanding of the causes of declines and extinctions
• Ongoing documentation of amphibian diversity, and how it is changing
• Development and implementation of long-term conservation programmes
• Emergency responses to immediate crises

The GAA website provides more detailed information on all of these topics.

© 2007. Patricia A. Michaels