Effects of Alternatives to Clearcutting on Invertebrate and Organic Detritus Transport From Headwaters in Southeastern Alaska

ISBN-13: 9781508448273 / Angielski / Miękka / 2015 / 34 str.

United States Department of Agriculture

Opis

We examined the transport of invertebrates and coarse organic detritus from headwater streams draining timber harvest units in a selective timber harvesting study, alternatives to clearcutting (ATC) in southeastern Alaska. Transport in 17 small streams (mean measured discharge range: 1.2 to 14.6 L/s) was sampled with 250- m-mesh drift nets in spring, summer, and fall near Hanus Bay at an ATC installation on Catherine and Baranof Islands. Samples were taken before (1996) and after (1999, 2000) nine timber harvesting treatments were applied. Invertebrate and organic detritus drift densities and community composition were used to assess treatment effects. A comparison of drift densities before and after treatment showed year-toyear differences comparable to natural variation at other sites in this study, but no clear relationship to intensity or type of timber harvest treatments. Natural variation in drift densities prevented detection of any potential timber harvesting effects. Coefficients of variation showed transport was most variable among streams, followed by seasons and then days."