Monday, May 26, 2008 - 10:15 AM
6

Bioassessment of the Hangman Creek watershed: Comparing macroinvertebrate assembleages versus habitat variables

Bruce A. Kinkead, Fisheries, Coeur d' Alene Tribe, 850 A St. P.O. Box 408, Plummer, ID 83851

In 2002 the Coeur d’Alene Tribe initiated a restoration project on Hangman Creek, a tributary of the Spokane River, which once supported adadromous fish. Key components of the bioassessment included; 1) Sampling of fish to determine distribution, population estimates, and their genetic makeup; 3) Water quality sampling to identify limiting factors; 3) Identify sources of erosion; 4) Measure habitat complexity; 5) Sample macroinvertebrates as support data for water quality and habitat analysis; and 6) Make restoration design recommendations. Macroinvertebrates were sampled at the same sites where temperature was measured with digital data loggers, and where pebble counts were sampled. Regression analysis of macroinvertebrate metrics versus Seven-day Average-Max-temperature and Percent Fine-sediments showed strong correlation (P<.05) for many indices with the notable exception of Percent Tolerant taxa and Shannon-Weaver Diversity. Macroinvertebrate indices were also used to compare the macroinvertebrate communities between tributary Rosgen channel types A, B, and C and mainstem C reaches. Rosgen A’s and B’s were not significantly different for both Percent-fines and temperature, as were Tributary C’s from mainstem C’s. Tributary A’s and B’s were significantly different than tributary C channels. The overall assessment indicates flow, fine sediments, temperature, and a lack of instream habitat complexity are limiting salmonid production.

 



Web Page: Rosgen Channel Types, Temperature, Percent Fines

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