Pitfall Trap Versus Area Searches for Herpetofauna Research

Area searches and pitfall trap methods are commonly used to quantify presence or abundance of reptile and amphibian species. However, most studies do not use both methods simultaneously. We compared these methods with respect to detectability of herpetofauna species and detection rates for individual species on public lands in east central Mississippi. We conducted area searches along 300 m2 belt transects measuring 50 x 6 m at distances of 0, 25, 50, 75, and 100 m from first and second order streams. Pitfall traps were placed along transects at 0, 50, and 100 m from streams. Transects were checked 2-3 times/year in 2001 and 2002. Transect data encompassed 84 surveys over 21 study sites. Twenty-four reptile species (741 individuals) and 17 amphibian species (615 individuals) were recorded during transect surveys. Nine reptile species (135 individuals) and 10 amphibian species (315 individuals) were captured using pitfall traps. Each method detected several species the other did not detect. Conclusions drawn from either method alone would differ significantly due to detection biases, but both methods together gave a more complete picture of the herpetofauna community. We encountered one possible bias that may have significantly altered pitfall data results. Depredation of captured animals in buckets by raccoons (Procyon lotor) was detected through the use of infrared-triggered cameras set near pitfall traps. We theorize that this type of depredation could influence herpetofaunal diversity detected by pitfall trapping. Furthermore, depredation of rare or protected herpetofauna captured in pitfall traps could have significant consequences for sensitive herpetofauna populations.

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