Sampling considerations for amphibian surveys: Evaluating risks of committing type I and type II errors

Global amphibian declines pose a major threat to the world's biodiversity. We examined the observation bias associated with volunteer based anuran surveys, such as the North American Amphibian Monitoring Protocol (NAAMP). We followed NAAMP protocol to examine if variation in the persons (1-3) in an observer unit affected observer error. We hypothesized that observation units with multiple observers have less observer bias and would better report anuran assemblages compared to single observers. Larger observer units had fewer incidences of false positive observations. Additionally, we attempted to determine which sampling method for the eastern hellbender (Cryptobranchus a. alleganiensis) had the highest detection rate. We examined the detection probability of three methods: visual encounter surveys (VES), nocturnal spotlighting, and un-baited trapping. After 200 search hours and 300 trap nights, one hellbender was detected during a VES. Due to the small sample size we were unable to determine site occupancy and detection probability.