Sampling Characteristics of Aquatic Funnel Traps for Monitoring Populations of Adult Rough-Skinned Newts (Taricha granulosa) in Lentic Habitats

Recent concern about amphibian declines has created a need for practical and effective sampling methods that will allow biologists to monitor populations. Aquatic funnel traps may provide an effective means to sample and monitor lentic, breeding adult salamander populations. However, before funnel traps can be used to assess population trends, the rela- tionship between capture rate and population density and the catchability of individuals within populations should both be examined. Using artificial ponds, we conducted 2 experiments that showed that the capture rates of aquatic funnel traps are representative of an adult population of Taricha granulosa and that gravid females in traps influence observed capture rates. These findings are important to biologists who may wish to reconsider their design of sampling re- gimes and interpretation of field data.