Leaf litterbags – Factors affecting capture of stream-dwelling salamanders

Abstract/Summary

Many standardized techniques are used to monitor terrestrial salamanders, but fewer protocols have been tested for inventorying stream-dwelling salamanders, especially larvae. One new method uses artificial refugia (leaf litterbags) placed in shallow streams. To test the utility of litterbags, we sampled three transects of 6 litterbags each (2 large, 2 medium, and 2 small) placed in five small, medium, and large streams in Great Smoky Mountains National Park, an area of high aquatic salamander diversity. We captured 690 larval, juvenile, and adult stream-dwelling salamanders of 11 different species from June to November 2000 in the 90 litterbags. Large and medium-sized litterbags were most effective at sampling salamanders in small streams, but all bag sizes worked equally well in medium and large streams. The number of salamanders captured varied seasonally, with most captures in June and July. The depth of bag submergence significantly influenced litterbag use by adult and larval salamanders, but had no effect on juvenile salamanders. Although the technique was effective for determining the presence of many salamander larvae, variation in the numbers of individuals captured and the inability to relate captures to overall abundance make it impossible to monitor trends without considerable additional effort. The ease of deployment and non-destructive methodology suggest that litterbags could be useful in determining salamander presence during inventory programs, especially when the time to sample a large number of sites is limited.