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

Timber harvest in the Pacific Northwest has resulted in a highly fragmented landscape, but there is no information on responses of amphibians to forest edges for this region. We investigated abundance of terrestrial and stream-dwelling amphibians on the inter-face of recent clearcuts and mature forest in the Siskiyou Mountains, Oregon, in summer and fall of 1998. We assessed relative abundance of terrestrial amphibians on four clearcut-forest transects with a combination of pitfall trapping and manual searches. Ensatinas and Del Norte salamanders, the most frequently recorded species, were found on all four sites. While we commonly captured ensatinas using both techniques, we caught most Del Norte salamanders during manual searches. For both species we found no differences in abundance associated with distance to forest edge. Lack of differences in salamander abundance among clearcut and adjacent forests may be related to large amounts of small woody debris that remained in the clearcuts. The abundance of larvae of tailed frogs and Pacific giant salamanders in five headwater streams was markedly lower in clearcuts than in downstream mature forest stands. No obvious differences existed for stream habitat variables across transects, but abundance of metamorphosed individuals and recruitment may be reduced in clearcut areas due to hotter and drier conditions during the summer.