Meeting Abstract
The semi-permeable skin of amphibians is particularly susceptible to water loss. As a result, amphibians experience more rapid rates of dehydration compared to other terrestrial vertebrate taxa. Many variables interact to determine these rates of water loss. We examined the effects of various environmental, biological and behavioral factors on the dehydration rates of green frogs (Lithobates clamitans) from central Massachusetts. Rates of evaporative water loss were tested at a range of temperatures (16.6-29.0ºC) and relative humidities (1.3-66.6%) for specimens ranging from 4.2-50.3 g. The effectiveness of a common behavior exhibited by many amphibians, the assumption of a water conserving posture, was also considered in determining rates of evaporative water loss. After running a multiple regression analysis, we found that environmental temperature (t = -5.21, p<0.0005), relative humidity (t = 11.419, p<0.0005), standard mass (t = 9.91, p<0.0005), and the relative time an individual assumes a full or near water conserving posture (t = 4.05, p<0.0005) significantly predicted dehydration rates of L. clamitans at a constant wind speed. Rates of evaporative water loss increased with increased environmental temperature, and decreased relative humidity, standard mass and the proportion of time specimens assumed a full or near water conserving posture in the time it took them to reach 80% of their standard mass.
