The Fall and Rise of the Amphibian Empire

In 1970, a group of experts on frogs, toads, salamanders, and caecilians noticed that populations of the Yosemite Park Toad in California had suddenly crashed. The habitat was suitable, there seemed to be nothing wrong but their numbers had crashed to very low levels. People scratched their heads and thought of it as just one of those random things that happens in the world; sometimes species disappear and sometimes there is no explanation for it.

Yosemite Park Toad (Anaxyrus canorus)_EN_© 2008 Devin Edmonds
Yosemite Park Toad (Anaxyrus canorus). Because declines have occurred in pristine areas in parks, no occurrences can be regarded as adequately protected. This species has been federally petitioned for listing under the Endangered Species Act in March 2000. In December 2002 the US Fish and Wildlife Service published a decision in the Federal Register that placed the toad on the “warranted-but-precluded” list due to higher priority listings. Photo Credit Devin Edmonds.

A few years later, in the late 1970s the same thing happened in Australia, the gastric brooding frog, actually not only did the population crash, the species disappeared almost overnight (two species, in fact) and were never found again.

Then in the mid-1980s in Costa Rica, the beautiful golden toad disappeared and has never been found again despite extensive efforts in searching over the past 30 years.

The amazing thing is that at the time that these isolated events took place none of the experts were talking to each other. It was before all of the amphibian experts had been organized into the IUCN Amphibian Species Survival Commission and it was before amphibians were assessed for The IUCN Red List.

Golden Toad (Incilius periglenes)_EX_© U.S. Fish and Wildlife Service
Golden Toad (Incilius periglenes) was formerly a common species, no specimen has been seen since 1989. It last bred in normal numbers in 1987, and its breeding sites were well known. In 1988, only eight males and two females could be located. In 1989, a single male was found, and was the last record of the species. Extensive searches since this time have failed to produce any more records. Its restricted range, climate change, chytridiomycosis and airborne pollution probably contributed to this species’ extinction. Photo Credit USFWS

In 1989, in Canterbury in the UK, IUCN organized a meeting of the world’s amphibian experts and they were amazed to discover that these were not isolated instances but there was a global problem. It took nineteen years after the Yosemite Park Toad populations crashed and another eight years after that to determine that the chytrid fungus was decimating amphibian populations throughout the world, but most notably in the species-rich rainforests of Central America. This realization has been one of the most publicized species extinction events in history and without the IUCN Red List there is little doubt that many of these extinctions might continue today. For those keeping track, that is 27 years of unmonitored and unchecked amphibian extinction, a process that may be occurring in other unassessed species groups.

Mantidactylus majori_LC_© 2008 Miguel Vences and Frank Glaw
Ivohimanita Madagascar Frog (Mantidactylus majori) is a wide-ranging frog species that lives in the rainforests and coastal littoral forest of Eastern Madagascar. It’s forest habitat is receding due to subsistence agriculture, timber extraction, charcoal manufacture, and invasive spread of eucalyptus, livestock grazing and expanding human settlements. Photo Credit Miguel Vences and Frank Glaw

In 2015, the avenues for communication between experts are far more extensive than in 1989, and the number of species experts in the IUCN network now exceeds 10,000 in over 130 species specialist groups, task forces, and Red List authorities. Amphibians still face the same increasing threats to biodiversity but now have a global network of conservationists, enthusiasts, and scientists working through organizations like the Amphibian Survival Alliance to halt the loss of amphibians. However, the taxonomic coverage of species that have been assessed is still far below what would provide a more comprehensive assessment of the status of global biodiversity and the threats and solutions for appropriate and effective biodiversity conservation.

Over the coming weeks, stay tuned for some of the current and future priorities for IUCN Red List assessments as we seek to build the IUCN Red List into a more comprehensive Barometer of Life.


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Craig R. Beatty and Simon Stuart

Changing Planet

Meet the Author
The International Union for Conservation of Nature is the world’s oldest and largest global environmental organization made up of more than 1,000 organizations, as well as 10,000 individual scientists and experts working on conservation around the globe. Perhaps we are best known for the IUCN Red List of Threatened Species, which is the global standard for species science and conservation information and the connection to human livelihoods and is celebrating 50 years of conservation action in 2014.