Terrestrial and stream amphibians across clearcut-forest interfaces in the Siskiyou Mountains, Oregon

Extensive timber harvest has occurred over the last 100 years in the Pacific Northwest (PNW), resulting in a high proportion of early-successional forest and forest edge. Prior studies indicate that several PNW amphibian species are associated with habitat conditions found primarily in old-growth stands. However, it is unknown whether increasing amounts of forest edges in the PNW might further reduce the abundance and distribution of those amphibian species. In a recent study, USGS scientist Bruce Bury and collaborators at the University of Montana investigated the abundance of terrestrial and stream-dwelling amphibians on the interface of recent clearcuts and mature forest in the Siskiyou Mountains, southern Oregon. They assessed relative abundance of terrestrial amphibians on four clearcut-forest transects. The most frequent terrestrial species were ensatina and Del Norte salamanders. There were no statistically significant differences in abundance associated with distance to forest edge for either species. Large amounts of downed wood in the clearcuts may have ameliorated harvest effects. In contrast, they found that the abundance of larvae of tailed frogs and Pacific giant salamanders in five headwater streams was markedly lower in clearcuts compared to mature forest stands downstream