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Diet and abundance of the southern two-lined salamander (Eurycea cirrigera) in an agricultural area, southwest Georgia

1024 681 Stroud Water Research Center

Muenz, T.K., S.W. Golladay, L.L. Smith, and G.Vellidis. 2008. Southeastern Naturalist. 7(4):691–704.

doi: 10.1656/1528-7092-7.4.691

Abstract

We sampled five stream reaches within an agricultural landscape in southwestern Georgia for benthic macroinvertebrates and larval amphibians from 2002 to 2003 to determine whether cattle grazing impacts these faunal components. Two of the stream reaches had been fenced to exclude cattle (buffered), whereas the other three were not, allowing cattle access to the streams (unbuffered). We captured larval Eurycea cirrgera (Southern Two-lined Salamanders) incidentally in our benthic samples and compared salamander capture rates between buffered versus unbuffered streams. We also examined salamander stomach contents relative to the composition and abundance of benthic macroinvertebrates, comparing these data by stream type as well. Overall, capture success for larval salamanders was higher at buffered sites. Midge larvae (family Chironomidae) were the most frequent invertebrate taxon detected, both in the benthic and stomach content samples; however, we also observed cladocerans, copepods, and ostracods in each sampling regime. A linear electivity index revealed that larval Southern Two-lined Salamanders showed slight dietary selection for midge larvae in the subfamily Tanypodinae. This finding, coupled with the observation that chironomid larvae composed over half of Southern Two-lined Salamanders stomach contents, suggests some preference or selection for this benthic group. However, larval Tanypodinae were found at all sites, suggesting that their identification to species level may be necessary to determine whether differences in the prey base explained differences in salamander selectivity between buffered versus unbuffered streams. Factors other than prey selectivity, such as instream habitat quality, may also have influenced larval salamander abundance.