Linking global warming to amphibian declines through its effects on female body condition and survivorship
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There is general consensus that climate change has contributed to the observed decline, and extinction, of many amphibian species throughout the world. However, the mechanisms of its effects remain unclear. A laboratory study in 1980–1981 in which temperate zone amphibians that were prevented from hibernating had decreased growth rates, matured at a smaller size and had increased mortality compared with those that hibernated suggested one possible mechanism. I used data from a field study of common toads (Bufo bufo) in the UK, between 1983 and 2005, to determine whether this also occurs in the field. The results demonstrated two pathways by which global warming may cause amphibian declines. First, there was a clear relationship between a decline in the body condition of female common toads and the occurrence of warmer than average years since 1983. This was paralleled by a decline in their annual survival rates with the relationship between these two declines being highly correlated. Second, there was a significant relationship between the occurrence of mild winters and a reduction in female body size, resulting in fewer eggs being laid annually. Climate warming can, therefore, act on wild temperate zone amphibians by deleteriously affecting their physiology, during and after hibernation, causing increased female mortality rates and decreased fecundity in survivors.
KeywordsBody size Bufo bufo Environmental temperatures Hibernation Mortality
I wish to thank an anonymous referee for detailed and constructive suggestions regarding the CMR analysis using MARK, and P. Rothery for assistance with the statistical analysis. I also wish to thank K. Moore who recorded the daily meteorological data for the Swanage area and the staff of the Swanage Tourist Information Centre for allowing me access to the weather data. The permanent marking of toads was licensed under the UK Animals (Scientific Procedures) Act 1986.
- Berger L, Speare R, Daszak P, Green DE, Cunningham AA, Slocombe R, Goggin CL, Hyatt AD, MacDonald KR, Hines HB, Lips KR, Marantelli G, Parkes HH (1998) Chytridiomycosis causes amphibian mortality associated with population declines in the rainforests of Australia and Central America. Proc Natl Acad Sci USA 95:9031–9036PubMedCrossRefGoogle Scholar
- Choquet R, Reboulet AM, Lebreton JD, Gimenez O, Pradel R (2005) U-CARE 2.2 user’s manual. CEFE, Montpellier, France (http://www.ftp.cefe.cnrs.fr/biom/Soft-CR/)
- La Marca E, Lips KR, Lötters S, Puschendorf R, Ibáñez R, Rueda-Almonacid JV, Schulte R, Marty C, Castro F, Manzanilla-Puppo J, García-Pérez JE, Bolaños F, Chaves G, Pounds JA, Toral E, Young BE (2005) Catastrophic population declines and extinctions in neotropical Harlequin frogs (Bufonidae: Atelopus). Biotropica 37:190–201CrossRefGoogle Scholar
- Pounds JA, Bustamante MR, Coloma LA, Consuegra JA, Fogden MPL, Foster PN, La Marca E, Masters KL, Merino-Viteri A, Puschendorf R, Ron SR, Sánches-Azofeifa GA, Still CJ, Young BE (2006) Widespread amphibian extinctions from epidemic disease driven by global warming. Nature 439:161–167PubMedCrossRefGoogle Scholar
- Puschendorf R (2003) Atelopus varius (harlequin frog). Fungal infection. Herpetol Rev 34:355Google Scholar