Effects of Timber Harvesting on Terrestrial Salamander Abundance and Behavior

Abstract

We examined the short-term (1 - 4 years postharvest) effects of 7 silvicultural treatments on terrestrial salamander populations at 4 sites in southwest Virginia and West Virginia. The 3 silvicultural treatments with the most canopy removal (4-7 m2 basal area Shelterwood, Leavetree, Clearcut) had significantly fewer salamanders than the control (p < 0.10) postharvest. No differences were found among treatments in age class distribution, the percent of females that were gravid, or average clutch size.

We tested the nighttime, surface-count census method for visibility and behavior-induced bias among silviculture treatments and estimated the proportion of a salamander population that is active on the surface in harvested and control habitats. Instantaneous rates of salamander activity ranged from 1.3 to 11.7% of the population for redback (Plethodon cinereus) and slimy salamanders (P. glutinosus). Timber harvest caused up to a 2-fold increase or decrease in activity rates. There was evidence for bias in the night census method, but differences were not consistent enough to suggest general bias corrections.

We also tested whether poorly fed salamanders exhibited risk-sensitive foraging in a dry environment in a laboratory experiment. Poorly fed salamanders were observed out of their simulated burrows less than well fed salamanders suggesting salamanders, particularly females and small adults, are risk-averse.