Varied effects of clear-cut logging on predators and their habitat in small streams of the Cascade mountains, Oregon

Assemblages of aquatic vertebrate and insect predators were inventoried in streams inold-growth and logged coniferous forests in the western Cascades of Oregon to assess effectsof clear-cut logging on stream communities. Effects associated with logging depended onstream size, gradient, and time after harvest. Clear-cut sections where the stream was stillexposed to sunlight (5-17 yr after logging) generally had greater biomass, density, andspecies richness of predators than old-growth (>450-yr-old) forested sections. Increases weregreatest in small (first-order), high gradient (10— 16%) streams, where clear-cut sites had bothgreater periphyton production and coarser streambed sediment than old-growth sites of similarsize and gradient. Effects on predators were mixed in larger, lower gradient streams,whereclear-cut sites showed accumulation of sediment and relatively small increases in periphytonproduction. Second-growth logged sections (12-35 yr after logging), reshaded by deciduousforest canopy, had lower biomass of trout and fewer predator taxa than old-growth sites.
Key words: trout, salamanders, insects, logging, sediment, periphyton, watershedmanagement