Fluctuations in amphibian populations: a meta-analysis Original Research Article

The magnitude of population fluctuations can affect the power of monitoring programs and the calculation of extinction risk. Because amphibian populations may be experiencing worldwide declines, understanding population fluctuations in amphibians is particularly important. I conducted a meta-analysis of population fluctuations in amphibian time series. I found that life history type, family and latitude were significant predictors of the coefficient of variation in population size. Life stage (e.g. tadpoles vs. adults) was a marginally significant predictor of the coefficient of variation. Coefficients of variation increased with series length in 27 of 29 time series that included 8 or more years. However, estimates of the coefficient of variation based on subsamples of longer time series often ranged two-to 10-fold, even with 5 or more years of data used. These results show that while some generalizations about amphibian population fluctuations might be possible, caution is necessary in selecting monitoring programs or calculating extinction risk from estimates of population variability.