Reed College Canyon

The Effects of Climate and Microclimate on the Surface Activity of the Oregon Salamander, Ensatina eschscholtzii oregonensis, in the Reed College Canyon

author: Duncan Stuart Michael Parks
advisor: Robert Kaplan
year: 1992

ABSTRACT: Amphibians face two central issues of physiological ecology: water balance and temperature balance with their environment. Amphibians' highly water-permeable skins and lack of physiological temperature regulation make these factors important, and a large body of research exists detailing the effects of these factors in the laboratory.

A field study was performed to determine the effects of these factors at both the climatic and microclimatic level on the surface activity of a plethodontid salamander, Ensatina eschscholtzii oregonensis. Rainfall over the previous 24 hours and daily low temperature were important climatic factors. Microclimatic air and soil temperature were shown to affect the weight of salamanders active at the surface and thus selectively affect surface activity.

The implications of limitations on surface activity for foraging time, energy balance, and reproductive success are discussed, as is the relative importance of physiological factors to the ecology of this population of Ensatina. More field study is needed to establish the importance in the field of the physiological factors studied in the laboratory.