Thesis
Woody debris and macroinvertebrate community structure of low-order streams in Colville National Forest, Washington
Washington State University
Master of Science (MS), Washington State University
2003
Handle:
https://hdl.handle.net/2376/141
Abstract
Buffer strips of riparian vegetation are frequently used to protect aquatic resources. With the suppression of natural fire events, however, riparian areas are often comprised of even-aged, small diameter trees. Such conditions produce dense stands which have the potential to contribute large amounts of wood to headwater streams. Thus far, little research has been conducted on how dense, even-aged, small-diameter riparian vegetation may affect aquatic resources. Benthic macroinvertebrate communities from forested headwater streams of Colville National Forest in northeastern Washington were used as indicators to determine the effects of large amounts of wood. Large amounts of wood could create wood jams that retain sediments that might interfere with macroinvertebrate biological processes such as respiration and egg laying. Therefore, lower abundance, richness, evenness and diversity of the macroinvertebrate community were hypothesized for sites with more wood. The numbers of wood pieces were counted to classify sites as "more wood" and "less wood" in each of three pairs on low-order streams. Physical parameters, such as width/depth ratio, slope, and substrate, were also analyzed to minimize potential differences that could influence the macroinvertebrate communities. Using three Surber samples from riffles at each site, the macroinvertebrate communities at "more wood" versus "less wood" sites were compared. Significant differences in the physical parameters were not detected between "more wood" and "less wood" sites. Average and total macroinvertebrate abundances and family richness were not significantly different, although total abundance for "more wood" sites was half that for "less wood" sites. Averages for Shannon-Wiener diversity index values and Pielou's evenness metric were not significantly different; but overall average values for these metrics were slightly higher for "more wood" sites. A strong, significant difference existed in the functional feeding group composition at "more wood" versus "less wood" sites. Therefore, the differences in macroinvertebrate communities, the abundances and functional feeding group compositions in particular, suggest large amounts of wood may alter stream ecology in low-order streams of Colville National Forest.
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Details
- Title
- Woody debris and macroinvertebrate community structure of low-order streams in Colville National Forest, Washington
- Creators
- Megan Bryn Rogers
- Contributors
- Barry C. Moore (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Environment, School of the (CAHNRS)
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; Pullman, Wash. :
- Identifiers
- 99900524869801842
- Language
- English
- Resource Type
- Thesis