Declining Amphibian Populations: The Problem of Separating Human Impacts from Natural Fluctuations

• Published in: Science (American Association for the Advancement of Science) Vol. 253; no. 5022; pp. 892 - 895
• Main Authors: Joseph H. K. Pechmann, Scott, David E., Semlitsch, Raymond D., Caldwell, Janalee P., Vitt, Laurie J., Gibbons, J. Whitfield
• Format: Journal Article
• Language: English
• Published: Washington, DC American Society for the Advancement of Science 23-08-1991; American Association for the Advancement of Science; The American Association for the Advancement of Science
• Subjects: Amphibians; Animal and plant ecology; Animal populations; Animal, plant and microbial ecology; Anura; Biodiversity; Biological and medical sciences; Biological diversity; Breeding; Breeding seasons; Caudata; Demecology; Depopulation; Ecology; Female animals; Fundamental and applied biological sciences. Psychology; Human beings; Human-environment interactions; Influence on nature; Plants and fungi; Ponds; Population size; Rain; Reptiles & amphibians; Synecology; Young animals; USA, South Carolina; Vertebrata; Fluctuations; Methodology; Population recruitment; Amphibia; Population decline; Anthropogenic factor
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.253.5022.892

Reports of declining amphibian populations in many parts of the world are numerous, but supporting long-term census data are generally unavailable. Census data from 1979 to 1990 for three salamander species and one frog species at a breeding pond in South Carolina showed fluctuations of substantial magnitude in both the size of breeding populations and in recruitment of juveniles. Breeding population sizes exhibited no overall trend in three species and increased in the fourth. Recent droughts account satisfactorily for an increase in recruitment failures, These data illustrate that to distinguish between natural population fluctuations and declines with anthropogenic causes may require long-term studies.