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Communication at the NABS Annual meeting, Keystone, 2000
(60) LONGITUDINAL PATTERNS IN FISH ASSEMBLAGE AND STREAM HABITAT RELATIONSHIPS: PART II. TEMPORAL DYNAMICS AND THE ROLE OF MIGRATION.
C.V. Baxter1, C.E. Torgersen1, H.W. Li2, and B.A. McIntosh3. 1Department of Fisheries and Wildlife, Oregon State University, Corvallis, OR, USA, 97331, 2Oregon Cooperative Fisheries and Wildlife Research Unit, Department of Fisheries and Wildlife, Oregon State University, Corvallis, OR, USA, 97331, 3Department of Forest Science, Oregon State University, Corvallis, OR, USA, 97331
Studies of longitudinal patterns in river fish assemblage structure are often limited to a summer "snapshot." Because we have little knowledge of how these assemblages change in time, we cannot fully understand the processes influencing fish distribution. The objective of this study was to examine the effects of habitat change and fish movement on longitudinal patterns in stream fish assemblage structure. We monitored changes in physical habitat factors, and we used repeated underwater surveys and radio-telemetry to quantify temporal dynamics of the fish assemblage in a wilderness stream in northeastern Oregon. We found that assemblage changes are associated with fish movement at multiple spatial and temporal scales. Seasonal migrations by several species created dramatic changes in longitudinal patterns and suggest the importance of landscape-scale habitat relationships to assemblage persistence. Diel movements changed with season and reflected variable use of habitat types within stream reaches. Patterns in stream fish assemblage structure are temporally dynamic and must be interpreted in context in order to explain natural variation and predict species responses. The extent of movement we observed suggests that current conceptual models of longitudinal fish distribution may have limited applicability to river fish assemblages of the Pacific Northwest.
Presented at 4:30 PM on Monday, May 29, 2000 in Spatial and Temporal Variation in Aquatic Communities II
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