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Presented at the NABS Annual meeting, Pittsburgh, Pennsylvania, 2002
in Land/Water Interfaces I
FLOODPLAIN PRODUCTIVITY IN SPRING BROOKS: NUTRIENTS, ALGAE, MACROINVERTEBRATES, AND FISH.
E.B. Snyder1, J.A. Chaffin2, D. Whited1, J.A. Stanford1, D.J. Eitemiller3, and C.P. Arango3. 1Flathead Lake Biological Station, The University of Montana, Polson, MT 59860, 2Department of Biology, Virgina Tech, Blacksburg, VA 24061, 3Department of Geography and Land Studies, Central Washington University, Ellensburg, WA 98926
The Yakima River (5th order), WA, consists of a series of at least 9 discrete alluvial flood plains distributed from headwaters to mouth (5 examined in this study). Patterns in habitat complexity indicate that typically the lower 3rd of each floodplain is more complex (p<0.05) as indicated by an increase in channel density and abundance of off channel habitats such as spring brooks. Nutrient concentrations (NO3+NO2, NH4, TP, SRP, DOC) were typically higher in spring brooks vs. the main channel whereas chlorophyll a concentrations were highly variable. Periphyton AFDM was higher in spring brooks (ANOVA, p=0.12). Macroinvertebrate density was comparable, but diversity was significantly lower in spring brooks (ANOVA, p<0.05). Finally, the abundance of juvenile salmonids was significantly greater spring brooks vs. all other channel types. Restoration of floodplain connectivity and resultant increases in habitat complexity will likely increase bioproduction, including the juvenile life history stages of endangered anadromous salmonids.
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