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LONGITUDINAL SUCCESSION IN IMPACT ASSESSMENT OF RIVER SYSTEM FISH COMMUNITIES 1
Author(s) -
Goldstein Robert M.
Publication year - 1981
Publication title -
jawra journal of the american water resources association
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.957
H-Index - 105
eISSN - 1752-1688
pISSN - 1093-474X
DOI - 10.1111/j.1752-1688.1981.tb02592.x
Subject(s) - species evenness , species richness , ecological succession , ecology , species diversity , diversity index , habitat , alpha diversity , biodiversity , environmental science , geography , biology
Longitudinal succession indicates that diversity and species richiess of fish communities increases with increasing river size (increasing habitat complexity and environmental stability). Cultural impacts tend to decrease diversity, species richness, and evenness. To assess the impacts of cultural events on the fish community of a river system, the bias caused by longitudinal succession was removed by normalizing diversity indices and species richness values for river size. The relationships between an impact index and the community parameters of evenness, normalized diversity, and normalized species richness were determined by regression analysis. Similar relationships were determined using nonnormalized data, and the results compared. The two sets of regressions were similar in terms of variance explained. Evenness, which is unaffected by longitudinal sucession, appears to be the most impact sensitive parameter. A major source of error and confusion rsults from introduced species which are simultaneously sources of biological impact and a component of the community. Numbers of introduced species tend to increase with both impact and river size.