Meeting Abstract
68.4 Jan. 7 Land Use Effects on Wood Frog (Rana sylvatica) Biophysical Ecology SIEG, A*; O’CONNOR, M; SPOTILA, J; Drexel University aes48@drexel.edu
Amphibians are important indicator species of ecosystem health but are declining worldwide at a faster rate than other vertebrate groups. Habitat loss is a major cause of this decline. As part of a broad-scale experimental study of effects of forestry techniques on amphibians, we measured microclimate variables in treated and control forest habitat and estimated potential rates of mass and energy exchange for wood frogs (Rana sylvatica) inhabiting each treated habitat. Daytime surface air temperatures (Mean ± 2 SE; ° C) were elevated in the clearcut treatment (21.8 ± 0.2) as compared to control (17.4 ± 0.1) and thinned canopy treatments (18.8 ± 0.2). However, vapor densities (g/m3) in the clearcut treatment both at the surface (12.7 ± 0.67) and under leaf litter (12.6 ± 0.37) were not significantly different from leaf litter vapor densities in the control (12.4 ± 0.22), thinned canopy (13.3 ± 0.12), and a groundwater drainage site (12.4 ± 0.22). Surface vapor densities were lower in the control (9.5 ± 0.14), thinned canopy (8.4 ± 0.37), and near the groundwater drainage site (10.1 ± 0.14). Physical models of frogs in each treatment at the surface and under leaf litter were used to measure body temperatures and rates of evaporative water loss (EWL). Mannequin EWL rates (g/hr) were similar within the clearcut treatment (surface 0.50 ± 0.05; leaf litter 0.51 ± 0.05) and the surface thinned canopy mannequins were comparably elevated (0.79 ± 0.15). Predicted surface EWL rates (g/hr) were consistent with the observed loss rates in each treatment (ranges: thinned 0.65 � 2.1; clearcut 0.31 � 0.97). We apply a new technique to the prediction of frog EWL under leaf litter and the application of frog mannequins to measuring field EWL over long time periods.
