MACROINVERTEBRATE COMMUNITY CONDITION ASSOCIATED WITH THE SEVERITY OF STREAMFLOW ALTERATION
ABSTRACT Natural streamflows play a critical role in stream ecosystems, yet quantitative relations between streamflow alteration and stream health have been elusive. One reason for this difficulty is that neither streamflow alteration nor ecological responses are measured relative to their natural e...
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Published in | River research and applications Vol. 30; no. 1; pp. 29 - 39 |
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Main Authors | , , |
Format | Journal Article |
Language | English |
Published |
Chichester
Blackwell Publishing Ltd
01.01.2014
Wiley Wiley Subscription Services, Inc |
Subjects | |
Online Access | Get full text |
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Summary: | ABSTRACT
Natural streamflows play a critical role in stream ecosystems, yet quantitative relations between streamflow alteration and stream health have been elusive. One reason for this difficulty is that neither streamflow alteration nor ecological responses are measured relative to their natural expectations. We assessed macroinvertebrate community condition in 25 mountain streams representing a large gradient of streamflow alteration, which we quantified as the departure of observed flows from natural expectations. Observed flows were obtained from US Geological Survey streamgaging stations and discharge records from dams and diversion structures. During low‐flow conditions in September, samples of macroinvertebrate communities were collected at each site, in addition to measures of physical habitat, water chemistry and organic matter. In general, streamflows were artificially high during summer and artificially low throughout the rest of the year. Biological condition, as measured by richness of sensitive taxa (Ephemeroptera, Plecoptera and Trichoptera) and taxonomic completeness (O/E), was strongly and negatively related to the severity of depleted flows in winter. Analyses of macroinvertebrate traits suggest that taxa losses may have been caused by thermal modification associated with streamflow alteration. Our study yielded quantitative relations between the severity of streamflow alteration and the degree of biological impairment and suggests that water management that reduces streamflows during winter months is likely to have negative effects on downstream benthic communities in Utah mountain streams. Published 2012. This article is a U.S. Government work and is in the public domain in the USA. |
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Bibliography: | ArticleID:RRA2626 istex:953418471DC24483B4A938E4387BFA8F405B7D23 ark:/67375/WNG-NW3BZK7T-Z ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 1535-1459 1535-1467 |
DOI: | 10.1002/rra.2626 |