|SREL Reprint #1844|
PUTTING DECLINING AMPHIBIAN POPULATIONS
IN PERSPECTIVE: NATURAL FLUCTUATIONS AND
ABSTRACT: Human impacts obviously have reduced or eliminated many
populations of amphibians and other organisms. Recent reports, however, have
suggested that declines and disappearances of amphibian populations over the
last two decades represent a distinct phenomenon that goes beyond this general
biodiversity crisis. We review the literature on natural temporal and spatial
variation in population sizes and examine techniques for analyzing trends in
abundance. Whether the recent declines and extinctions of isolated, protected
amphibian populations exceed expected natural fluctuations remains equivocal.
The suggestion that amphibians are particularly sensitive bioindicators of
anthropogenic stresses has not received adequate study, and to our knowledge,
no evidence has been presented to substantiate it. Although concern about the
status of amphibian populations is clearly warranted, formulation of appropriate
null hypotheses and further study are needed.
SREL Reprint #1844
Pechmann, J.H.K. and H.M. Wilbur. 1994. Putting declining amphibian populations in perspective: natural fluctuations and human impacts. Herpetologica 50:65-84.