Headwater streams and timber harvest, channel, macroinvertebrate, and amphibian response and recovery

Abstract

Abiotic and biotic responses of 15 first-order streams to timber harvest were monitored at four sites in Washington's Coast Ranges (six watersheds clearcut to streambanks; four clearcut with stream buffers; and four references). Surveys of geomorphology, macroinvertebrates, and amphibians were conducted in 1998 (baseline), 1999 (immediately postharvest), 2000 (macroinvertebrates only) and 2001. Logging slash immediately covered or buried clearcut channels with 0.5 to 2 meters of slash, increasing roughness and trapping fine sediments, and slash still dominated channel conditions in 2001 when fine sediment fractions remained elevated relative to reference streams. In buffered and reference streams, particle size distributions were almost unchanged. Buffer blowdown was extensive (33% to 64%); increased light stimulated streamside vegetation. In 1999, clearcut streams supported higher macroinvertebrate densities of collectors and shredders, likely due to increased detrital resources. Collector response persisted into 2001, and new responses included higher overall macroinvertebrate biomass in buffered streams. No macroinvertebrate groups declined significantly in the three summers after harvest. Clearcutting to stream channels appeared to have short-term negative effects on local giant salamander and tailed frog populations but not torrent salamanders. Copyright © 2007 by the Society of American Foresters.