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Fire and fish: fish habitat attributes of watersheds with pulse and press disturbance patterns

Author(s): D. Cross
Editor(s): Jason Greenlee
Year Published: 1997

The native salmonids of the Idaho Panhandle National Forests, bull chaff (Salvelinus confluentus) and westslope cutthroat trout (Oncorhynchus clarki lewisz) evolved with natural pulse disturbances of which the most common were fire and flood. These fish are indicator species in the Forest Plan, listed as sensitive species by Region 1 of the Forest Service and as species of special concern by the Idaho Department of Fish and Game. To address the needs of these species, and especially the bull charr with the recent petition for listing under the ESA, the Idaho Panhandle National Forests began habitat typing watersheds in the upper Spokane River ecosystem in 1991. A physical habitat typing protocol developed in Region 5 of the USFS and modified for the waters of northern Idaho was used to monitor any changes in fish habitat which may have occurred due to land management prescription. Of the attributes described by the methodology, mean residual pool volume and residual poo1 depth have been emphasized in analysis because of the value of pools in the stream ecology of bull charr and westslope cutthroat trout for rearing and overwintering habitat. Data was stratified from press and pulse disturbed watersheds. Changes in the quality (volume and depth) and quantity of pool habitat as a result of channel destabilization has a negative influence on carrying capacity as demonstrated by distribution and abundance of the two species in the Coeur d'Alene and St. Joe rivers, and appears to influence the distribution of spawning bull charr. Fish habitat attribute data from stream reaches of watersheds with pulse disturbance patterns in the upper St. Joe basin provide a reasonable standard by which to judge deviations seen in stream reaches of basins of similar geology, channel type, elevation, and forest type where press disturbance has been common for the last 50 to 90 years. These data suggest that the two types of disturbance result in habitat features with differing values relative to quantity and quality of the habitat features and resulting in changes in the distribution and success of persistence in the native assemblages of bull chan and other native fishes.

Citation: Cross, D. 1997. Fire and fish: fish habitat attributes of watersheds with pulse and press disturbance patterns, p. 59-64 in Greenlee, J. M., Proceedings: First Conference on Fire Effects on Rare and Endangered Species and Habitats. Coeur d'Alene, Idaho. International Association of Wildland Fire,Fairfield, WA. November 1995, 343 p.
Topic(s): Fire Effects, Ecological - Second Order, Wildlife, Fire & Wildlife, Fish
Ecosystem(s): None
Document Type: Conference Proceedings
NRFSN number: 18528
FRAMES RCS number: 37853
TTRS (Tall Timbers Research Station) Number: 12374
Record updated: Nov 23, 2018