Climate variability in regions of amphibian declines

We explored the relationship between amphibian declines and climate variati ons in Colorado (U.S.A.), Puerto Rico, Costa Rica-Panama, and Queensland (A ustralia) through two sources of dater output from the National Center for Environmental Prediction "reanalysis system" and area-averaged station data . The reanalysis system merges observations from airplanes, land stations, satellites, ships, and weather balloons with output from a weather-forecast model to create global fields of atmospheric variables. Station data consi sted of temperature and precipitation measured with thermometers and rain g auges at fixed locations. Temperatures were near normal in Colorado when th e amphibian declines occurred In the 1970s, whereas in Central America temp eratures were warmer than normal, especially during the dry season. The sta tion data from Puerto Rico and Australia indicated that temperatures were a bove normal during the period of amphibian declines, but reanalysis did not show such a clear temperature signal, Although declines occurred while the temperature and precipitation anomalies in some of the regions were large and of extended duration, the anomalies were not beyond the range of normal variability. Thus, unusual climate, as measured by regional estimates of t emperature and precipitation, is unlikely to be the direct cause of amphibi an declines, but it may have indirectly contributed to them. Previous resea rchers have noted that the declines appear to have propagated from northwes t to southeast from Costa Rica to Panama and from southeast to northwest in Queensland, Australia, Wind has the potential to transport pathogens that cause amphibian mortality. The mean direction of the near-surface winds ten ded to parallel the path of amphibian declines from July-October in Central America and from May-July in Australia. The wind direction was highly vari able, however, and the propagation rate of amphibian declines was much slow er than the mean wind speed. In addition, the most likely pathogen is a chy trid fungus then does not produce desiccation-resistant spores. Thus, if wi nd is involved in the propagation of amphibian declines, it is through a co mplex set of processes.