Meeting Abstract
72.6 Sunday, Jan. 6 Linking Amphibian Physiology to Physical Characteristics of its Forestry-Altered Habitat SIEG, A.E.*; O’CONNOR, M.P.; DUNHAM, A.E.; SPOTILA, J.R.; Drexel Univ., Philadelphia; Drexel Univ., Philadelphia; Univ. of Pennsylvania, Philadelphia; Drexel Univ., Philadelphia aes48@drexel.edu
Amphibians are declining worldwide at a faster rate than any other vertebrate group and habitat loss is a major cause of this decline. An experimental study of forestry impacts on terrestrial amphibians created logged (thinned and clearcut) forest habitat surrounding breeding ponds in Missouri. We estimate potential rates of mass and energy exchange for native wood frog (Rana sylvatica) inhabitants over hourly, daily, and yearly time frames in the heterogeneous landscape created both experimentally and by existing topography, forest floor leaf litter, and climatic variables. We investigate acute tolerance limits over the range of possible body temperature and hydration levels in amphibian physiology by measuring performance breadths based on hop lengths. We also measure metabolic rates at varying combinations of body temperature and hydration, a physiological alteration that becomes important over longer time frames. We present our estimates of evaporative water loss rates and body temperatures experienced by amphibians in the field based on quantification of weather station variables in each treatment and in a groundwater drainage ravine � the common topographical variant within treatments � and classical biophysical equations. Estimates are also made with physical models of frogs cut from sponges and plaster casts at each site. Temporal variation in biophysical characteristics was significant in terms of diurnal variation, consecutive days following a rain event, intra- and inter-seasonal variation. This overall approach emphasizes the primacy of water as a resource in amphibian physiological ecology and delineates precisely under which spatial and temporal scales different logging techniques affect amphibians. These are concepts often missing in amphibian conservation.
