Benthic macroinvertebrate communities in nonregulated and regulated waters of the clearwater river, Idaho, U.S.A.
作者:
Mark D. Munn,
Merlyn A. Brusven,
期刊:
Regulated Rivers: Research&Management
(WILEY Available online 1991)
卷期:
Volume 6,
issue 1
页码: 1-11
ISSN:0886-9375
年代: 1991
DOI:10.1002/rrr.3450060102
出版商: John Wiley&Sons, Ltd
关键词: Benthic communities;Regulated rivers;Discontinuity Longitudinal changes
数据来源: WILEY
摘要:
AbstractBenthic macroinvertebrates were examined over a two‐year period in nonregulated, regulated, and semiregulated reaches of the Clearwater River in northern Idaho. Macroinvertebrate communities in the nonregulated reach above Dworshak Reservoir were taxonomically diverse at all stations. In contrast, the macroinvertebrate community in the regulated reach of the North Fork of the Clearwater River (NFCR) was severely altered with high macroinvertebrate abundance and low taxa richness (2 to 8 taxa). Orthoclad chironomids dominated this reach composing between 68 and 99 per cent of total benthic invertebrate numbers. The mayflyEphemerella infrequenswas the only other macroinvertebrate to be abundant in the regulated reach. The major factors contributing to the simplified macroinvertebrate community are reduced habitat diversity, fluctuating water levels, altered thermal regime, and possibly an altered food supply. The effects of the dam were mitigated in the semiregulated Mainstem of the Clearwater River (MSCR) due to the merger of a nonregulated fork entering 2.5 km downstream from the dam. The macroinvertebrate community in the semiregulated MSCR was more complex than the regulated reach with a community structure resembling that found above the reservoi
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