| The primary industries of Prince of Wales Island are tourism, timber harvesting and sport and commercial fisheries. Because timber harvesting is a disturbance that affects both physical and biological characteristics of adjacent streams and rivers, the effects of clear-cutting on spawning and rearing habitats of commercial and sport fish species have been investigated. However, many small fishless headwater streams in upland forests, with potential sources of benthic invertebrates as major food items for economically important fish species have received little attention. In an effort to assess the effects of timber harvest practices in upland forests, benthic invertebrate community structure was contrasted among four dominant forest management conditions and instream habitats. Timer harvest caused increases in invertebrate richness, densities and biomass relative to old growth conditions, particularly in second growth managements with an alder-dominated riparian vegetation. Large woody debris and gravel habitats supported high densities and biomass of invertebrates. In addition, large woody debris also supported a richer and more diverse fauna than either cobble or gravel substrates. Alternatives to clear-cut harvesting should be employed for the maintenance of wood recruitment into streams and growth of red alder along riparian margins. |
