Results from the Global Amphibian Assessment
The Global Amphibian Assessment was completed in 2004 as an IUCN-led initiative, the results of which were included in the 2004 IUCN Red List (Stuart et al. (2004) Status and trends of amphibian declines and extinctions worldwide. Science, 306, 1783-1786).
© Paul Crump
© Dr Ian Stephen
© Monika Böhm
© Ron Holt, Courtesy Atlanta Botanical Garden
© Gerry Marantelli
© Francisco José López-López
Many amphibian species are on the brink of extinction with 427 species (7.4%) listed as Critically Endangered. 22.5% of species are too poorly known to assess and have been listed as Data Deficient – this could considerably underestimate the level of threat.
Only 34 species of amphibian are reported to have become extinct since 1500, but this situation may be worsening because nine of these extinctions have taken place since 1980. The Panama Golden frog Atelopus zeteki (photo) is currently listed as Critically Endangered.
122 species have been listed as Possibly Extinct, 113 of which have not been recorded since 1980, indicating a rapid decline. The Mountain Chicken frog Leptodactylus fallax (photo) has been listed as Critically Endangered because of an estimated population decline of more than 80% over the last ten years.
The results of the Global Amphibian Assessment indicate that amphibians are more threatened than birds or mammals, with 1,856 species (32.5%) being globally threatened.
Declines in amphibian species have been noted as being most prevalent among Neotropical montane, stream-associated habitats.
The most serious known threat to amphibians is Chytrid fungus. The disease can cause dramatic mortality in amphibians and therefore needs to be contained and controlled to prevent it from spreading and devastating amphibian populations. The lemur leaf frog Hylomantis lemur is Critically Endangered, with population declines most likely to be due to chytridiomycosis.
Many species are declining for unknown reasons (enigmatic declines). This complicates efforts to design and implement conservation measures to stem the decline of the world's amphibians. While the Dyeing Poison Arrow frog Dendrobates azureus is classed as Least Concern based on stable population trends, other species are not so lucky.
Enigmatic declines have been particularly prominent in South and Central America and Australia. More research is required to pinpoint threats affecting amphibians in these regions. Hyloscirtus tigrinus, for example, has been assessed as Data Deficient since not much is known about its distribution in South America.
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