Record Details
A hierarchical stream habitat classification system: development and demonstration
ScholarsArchive at Oregon State University
| Field | Value |
|---|---|
| Title | A hierarchical stream habitat classification system: development and demonstration |
| Names |
Frissell, Christopher A.
(creator) Liss, William J. (advisor) |
| Date Issued | 1985-06-10 (iso8601) |
| Note | Graduation date: 1986 |
| Abstract | Classification of Streams and stream habitats is useful for research involving establishment of monitoring stations, determining local impacts of land use practices, generalization from site-specific data, and assessment of basin-wide, cumulative impacts of human activities on streams and their biota. This thesis presents a framework for a hierarchical classification system, entailing an organized view of spatial and temporal variation between and within stream systems. Stream habitat systems, defined and classified on several spatio-temporal scales, are associated with watershed geomorphic features and events. Variables selected for classification define relative long-term capacities of systems, not simply short-term states. Streams and their watershed environments are classified within the context of a regional biogeoclimatic classification. The framework is a perspective that should allow more systematic interpretation and description of watershed/stream relationships. The classification system was used to assess changes in stream habitat caused by logging and debris removal in a fourth-order stream in the High Cascades of Oregon. Habitat organization, trout density, and habitat use were compared in logged (clear-cut, 1962) and forested stream sections in the same stream segment. The hierarchical classification system allowed pool/riffle habitats to he related to the geomorphic history of different stream reaches. Due to the presence of large debris dams and abundant woody debris, forested reaches varied in morphology and encompassed a wide array of pool/riffle habitats, including debris-created pools and side channels. Clear-cut reaches were relatively homogeneous, and were dominated by boulder-formed habitats. Although trout density was highly reach-specific, total density of the forested section was 40% greater than that of the clear-cut section. The smallest size class was absent and large (>14 cm) individuals were uncommon in clear-cut reaches. A regression model showed that most of the variation among reaches in trout density was related to the relative area comprised of six key pool/riffle types. The habitat classification system proved useful in demonstrating that the forested stream section, because of its diversity of pool/riffle types, may best provide the range of habitats required by all size classes through changing streamflow conditions. |
| Genre | Thesis/Dissertation |
| Topic | Stream ecology -- Oregon |
| Identifier | http://hdl.handle.net/1957/22338 |
