Short-term response of herpetofauna to timber harvesting in conjuction with streamside-management zones in seasonally-flooded bottomland-hardwood forests of southeast Texas

Abstract

Impacts of selection-cutting and clearcutting on local herpetofauna populations were evaluated. Also, the effectiveness of a streamside-management zone (SMZ) implemented within harvested areas was assessed. Research was conducted at Forest Lake Forest and Wildlife Research Station, located in southeast Tyler County, Texas. A randomized block design experiment was used. Three 24-ha blocks, bisected lengthwise by an intermittent stream, were subdivided into three (8-ha) plots consisting of a control, selection-cut, and clearcut. A SMZ was established 20. 1-m from each bank of the intermittent stream and subjected only to limited selection-cutting. Herpetofauna were censused using 144 drift fence arrays, consisting of pit-fall and double-ended-wire funnel traps. Traps were checked for 180 days, between 24 January 1993 and 22 June 1994. During this time, 8194 individual reptiles and amphibians comprising 38 species were captured. Differences in abundance between control and both timber harvesting treatments and between SMZ within control and SMZ within both timber harvesting treatments were analyzed utilizing a one-way ANOVA and multiple comparison tests for the 15 most commonly captured species. The remaining 23 species were rarely encountered, preventing meaningful statistical evaluation. Selection-cutting did not decreased abundance of any species. Selection-cutting increased abundance of 2 species and had no effect on the remaining 13 species. Clearcutting decreased abundance of one species. Clearcutting increased abundance of 3 species and had no impact on I I species. No species decreased in abundance in SMZs of either selection-cut or clearcut plots. Two species increased in abundance in SMZs implemented within selection-cuts. Two species increased in abundance in SMZs implemented within clearcuts. Both selection-cut and clearcut treatments possessed greater species diversities than control areas. In addition, selection-cut and clearcut Sws possessed greater species diversities than control SMZS. In the short-term, genotypic species of seasonally-flooded-bottomland forests suffer greatest impact after timber harvest, while more generalist species remain stable or increase in abundance. Selection-cutting appeared to have the least harmful effect on herpetofauna, as this method maintains the essence of natural forests by allowing heterogeneity in stand age and habitat. The continued use of SMZs is recommended. These areas provide a refugium and may act as centers of dispersal for detrimentally impacted species to repopulate the new emerging forest.