Trophic patterns of an insectivorous bat community foraging over urban and pristine streams as revealed by stable isotope and fecal analyses

The North Buffalo Creek wastewater treatment plant (WWTP) has a demonstrated impact on basal stream components and the foraging activity of common bat species in the watershed. I examined trophic patterns of common bat species upstream and downstream of the WWTP and in the relatively pristine Uwharrie National Forest. I used stable isotopes and fecal analysis to examine trophic positions and diets of bat species at these sites. Bat species in the Uwharrie National Forest had distinct delta15N and delta 13C signals whereas these isotope signals converged among bat species along North Buffalo Creek. Fecal analysis showed that in the Uwharrie National Forest diets of bats differed among the species whereas diets were similar along North Buffalo Creek. Bi-plots of delta15N and delta 13C for bats and insects support fecal analyses. In the Piedmont of North Carolina, the unique trophic roles of particular bat species are lost along North Buffalo Creek.