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The Aquatic Insects, with Emphasis on Trichoptera, of a Colorado Stream Affected by Coal Strip-Mine Drainage
Steven P. Canton and James V. Ward
The Southwestern Naturalist
Vol. 25, No. 4 (Feb. 16, 1981), pp. 453-460
Published by: Southwestern Association of Naturalists
Stable URL: http://www.jstor.org/stable/3670844
Page Count: 8
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Benthic sampling was conducted year-round over a 2 year period (July 1975-June 1977) on Trout Creek, a mountain stream in northwestern Colorado, to assess the effects of coal mine drainage on the stream insect community. Samples were taken monthly from rubble riffles above and below drainage from unreclaimed mine spoils. Unexpectedly, aquatic insects exhibited similar mean density and biomass values at each site and accounted for at least 95% of the total benthic standing crop above and below the mine. The number of insect taxa was similar and diversity index values did not vary significantly between sites. However, the community structure of the two sites did differ. Certain taxa were most abundant at the upstream site (Prostoia besametsa and Lepidostoma moneka), while others were more abundant at the downstream location (Agapetus boulderensis, Glossosoma ventrale, and Hydropsyche spp.). The greatest difference between the two sites was the differential importance of Trichoptera. At the upper site, caddisflies accounted for 39% of the benthic density due to the abundance of four families (Lepidostomatidae, Glossosomatidae, Brachycentridae, and Hydroptilidae). Trichopterans accounted for 60% of the benthic density below the mine, due primarily to the abundance of Hydropsychidae, and especially Glossosomatidae. This study points to the importance of community structure analysis in assessing effects of changes in environmental conditions in stream systems.
The Southwestern Naturalist © 1981 Southwestern Association of Naturalists