Amphibian declines and environmental change: Use of remote-sensing data to identify environmental correlates

Populations of many amphibian species are declining worldwide, and a few species appear to have become extinct, In an attempt to evaluate the potential usefulness of remote-sensing techniques as a tool for identifying the causes of These declines, we compiled a database that contains descriptions of 120 localities, both at which declines have been documented and at which no declines are yet known. Tbe number of species involved, dates and degree of declines, habitat characteristics, and other factors are provided for each locality. Four relatively undisturbed areas in northeastern Australia, Costa Rica-Panama, central Colorado, and Puerto Rico were chosen for examination of environmental correlates coincident with mass mortalities at these localities. We used data predicted by models or collected by satellites, airplanes, or direct sampling on the ground to evaluate variations over time In temperature, precipitation, wind direction, UV-B radiation, and concentrations of certain contaminants at these sites. We asked whether unusual changes in these environmental variables occurred either just in advance of or concurrent with dates of amphibian mass mortalities, The variation in certain environmental variables documented by others (Alexander & Eischeid 2001; Middleton et cit. 2001; Stallard 2001 [all this issue]) appears unlikely to have directly caused amphibian deaths. But correlations between these environmental changes and the occurrence of amphibian die-offs, invite further investigation into synergistic interactions among environmental variables and possible indirect causal relationships.