Stream Characteristics and Aquatic Macroinvertebrates Following Wildland Fire in Western Wyoming

We examined fire effects on aquatic habitat and benthic macroinvertebrates in streams of the Little Granite Creek watershed, Wyoming, where a wildfire burned approximately 75% of one basin, while an adjacent (reference) basin remained largely unburned. Embeddedness (% of channel surface covered by fines) was substantially greater in the burned stream (92%) than in the reference stream (59%). Stream temperatures were consistently higher in summer and lower in fall in the burned drainage, reflecting basin differences in vegetative cover. Although macroinvertebrate taxonomic richness was similar in both streams (45 families), benthic communities in the burned stream were dominated by Dipterans (77% total abundance) with 22% EPT, while communities in the unburned stream were composed of 46% Dipterans and 53% EPT. Benthic communities in both streams had similar proportions of generalist feeders (mostly Chironomidae, 31 to 33%), and collector-gatherers and scrapers (mostly Baetidae, 17%). However, collector-filterers (mostly Simulidae) accounted for over 40% of the total abundance in the burned stream, and only 3% in the unburned stream. Despite differences between the study basins, fire effects in the Little Granite Creek watershed are less dramatic than those reported from other regions.