Relations between the diversity of juvenile anadromous salmonids and pool features
were examined in a managed and a pristine watershed in Oregon during the summer of
1990. There were no differences (p>0.05) in pool depth, velocity or pool wood volumes
between streams. However, the pristine system had twice the number of pools within
similar lineal distances. Pools in the pristine system also had larger substrates (percent
dominant within pools) and smaller pool area (p=0.01). Fish diversity was found to be
greater in pools in the pristine system than in the managed system using the Simpson's
Diversity and Shannon Evenness indicies (p=0.01). The Shannon-Wiener Diversity
index did not show any differences between streams. The difference in assemblage
diversity was due to differences in relative abundance and not species richness. Relative
abundance of juvenile steelhead and cutthroat trout and coho salmon was more even in
Cummins Creek, the pristine system, than in Cape Creek, the managed system. Relative
abundance of coho increased in the managed system possibly due to a change in pool
habitat characteristics, whose conditions favored coho salmon, but this relationship was
not clear. This study emphasizes the importance of assessing communities of juvenile
anadromous salmonids as opposed to studies involving a single species. Past land
management activities have focused upon single species' with regards to a particular
habitat component, which has decreased biodiversity and changed stream habitat
characteristics through cumulative effects. Resource managers should examine
interactions between habitat characteristics and salmonid communities in order to
maintain biological diversity or risk creating favored habitat for a single species within
stream systems. / Graduation date: 1997
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/34084 |
| Date | 18 November 1996 |
| Creators | Haapala, Deborah L. |
| Contributors | Reeves, Gordon H. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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