HR: 15:10h
AN: B32C-06    [PDF]
TI: The Effects of Forest Disturbance on Macroinvertebrates in Western Oregon Headwater Streams - Patterns in Existing Databases
AU: * Herlihy, A T
EM: Alan.Herlihy@orst.edu
AF: Department of Fisheries and Wildlife, Oregon State University, Nash Hall 104, Corvallis, OR 97331 United States
AU: Li, J
EM: Judith.Li@orst.edu
AF: Department of Fisheries and Wildlife, Oregon State University, Nash Hall 104, Corvallis, OR 97331 United States
AU: Gerth, B
EM: gerthw@onid.orst.edu
AF: Department of Fisheries and Wildlife, Oregon State University, Nash Hall 104, Corvallis, OR 97331 United States
AU: Banks, J
EM: banksj@onid.orst.edu
AF: Department of Fisheries and Wildlife, Oregon State University, Nash Hall 104, Corvallis, OR 97331 United States
AB: As part of a research project investigating the effects of forest harvest practices on stream macroinvertebrates, we compiled existing data for Western Oregon headwater forest streams. The compiled database consists of 168 sites with watershed areas less than 10 square km that had measurements of stream macroinvertebrates, fish, physical habitat, water chemistry, and watershed land cover. The source of the data is from surveys conducted for EPA's EMAP program, the state of Oregon's Salmon Plan monitoring, and our own sampling efforts between 1994 and 2000. Almost all sites in the database were selected using the randomized EMAP survey design so they constitute a representative sample of all streams in this population. The streams in our dataset typically had mean wetted widths of 1-5 m, mean thalweg depths of 8-34 cm, and channel slopes of 1-15%. Watersheds for these sites were delineated and data on forest condition and logging history were clipped from available GIS layers. There were 189 macroinvertebrate taxa at the 168 sites with richness at individual sites ranging from 7 to 71 taxa. Ordination of the macroinvertebrate assemblages using NMS resulted in a 3 dimensional solution which accounted for 78% of the variation in the similarity among sites and demonstrated clear patterns in taxonomic composition with Baetis, Epeorus and Chironominae having the highest correlations with the ordination axes. Axes 1 and 2 each explained about 30% of the variation and were strongly correlated with substrate size, site slope and elevation. The third axis explained 17% of the variation and was correlated most strongly with watershed indices of forest logging history.
DE: 0400 Biogeosciences
DE: 1803 Anthropogenic effects
DE: 1845 Limnology
SC: Biogeosciences [B]
MN: 2003 Fall Meeting