The Global Amphibian Decline:
Trends, Causes, and Challenges

Cricket tree frog (Hyla picta)
photo by Jeff Chow

Introduction

Global Trends
North America
Central and South America
Australia
Europe

Causes
Habitat Modification
Exotic Species
Acidification and Toxic Contiminants
Ultraviolet Radiation
Climate Change
Pathogens

Challenges

Bibliography

Links

Regional Trends: Central and South America

Latin America, comprised of Central and South America, harbors a highly diverse amphibian fauna, but dramatic amphibian population declines are limited to a few well-known declines. These include the sudden, virtual disappearance of the once-abundant golden toad (Bufo periglenes) in Costa Rica's Monteverde Cloud Forest Preserve. In 1987, over 1500 toads would gather to mate at temporary ponds; several years later, from 1990-1992, researchers could not find a single individual despite intensive surveys. At the same time, the harlequin frog (Atelopus varius) and members of six other amphibian families also became scarce at Monteverde. Other well-documented incidences include declines and mass mortality events among suites of amphibian species at Las Tablas, Puntarenas, Costa Rica and the Reserva Forestal Fortuna in Chiriqui, Panama. Less well-publicized declines have also been reported in Honduras, Venezuela, Ecuador, and Brazil.

In 1999, series of three workshops for herpetologists based in Latin America revealed that population declines are widespread in the region. At least thirteen countries have experienced declines in their amphibian populations, and in 53 cases species are currently thought to be extinct or extirpated in a country where they once occurred. Declines or extinctions have affected 30 genera and nine families of amphibians. Most of these declines have occurred in remote highlands (above 500m elevation in Central America and over 1000m in the Andes) and have affected stream-associated species more than terrestrial species. At lowland sites, many frog populations have been affected by a variety of human activities, such as habitat destruction.

These declines began with northern sites in the 1970s, with most of the declines throughout Latin America occurring in the 1980s, and new declines occurring at some central and southern sites in the 1990s. Dramatic declines, in which the loss of a population or species occurred within three years, have been observed in Costa Rica, western Panama, Venezuela, and Ecuador.