Persistent effects of wildfire and debris flows on the invertebrate prey base of rainbow trout in Idaho streams

Northwest Science
By: , and 

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Abstract

Wildfire and debris flows are important physical and ecological drivers in headwater streams of western North America. Past research has primarily examined short-term effects of these disturbances; less is known about longer-term impacts. We investigated wildfire effects on the invertebrate prey base for drift-feeding rainbow trout (Oncorhynchus mykiss, Walbaum) in Idaho headwater streams a decade after wildfire. Three stream types with different disturbance histories were examined: 1) unburned, 2) burned, and 3) burned followed by debris flows that reset channel morphology and riparian vegetation. The quantity of macroinvertebrate drift (biomass density) was more variable within than among disturbance categories. Average body weight and taxonomic richness of drift were significantly related to water temperature and influenced by disturbance history. During the autumn sampling period, the amount of terrestrial insects in rainbow trout diets varied with disturbance history and the amount of overhead canopy along the stream banks. Results indicate that there are detectable changes to macroinvertebrate drift and trout diet a decade after wildfire, and that these responses are better correlated with specific characteristics of the stream (water temperature, canopy cover) than with broad disturbance classes.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Persistent effects of wildfire and debris flows on the invertebrate prey base of rainbow trout in Idaho streams
Series title Northwest Science
DOI 10.3955/046.085.0105
Volume 85
Issue 1
Year Published 2011
Language English
Contributing office(s) Forest and Rangeland Ecosystem Science Center
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Northwest Science
First page 55
Last page 63