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Does water abstraction from unregulated streams affect aquatic macrophyte assemblages? An evaluation based on comparisons with reference sites
Author(s) -
Chessman Bruce C.,
Royal Meredith J.,
Muschal Monika
Publication year - 2008
Publication title -
ecohydrology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.982
H-Index - 54
eISSN - 1936-0592
pISSN - 1936-0584
DOI - 10.1002/eco.8
Subject(s) - macrophyte , streams , entitlement (fair division) , environmental science , hydrology (agriculture) , abstraction , ecology , range (aeronautics) , geography , biology , computer science , geology , computer network , philosophy , materials science , geotechnical engineering , epistemology , composite material
Aquatic and amphibious macrophytes were surveyed during two seasons at 85 sites on unregulated streams in northeastern New South Wales, Australia, during a period of prolonged and recurring drought. Fifty‐four of these sites were designated as reference sites with respect to water abstraction because upstream entitlement for abstraction was less than 1% of their mean annual flow (MAF). The remaining sites had an average of 4% of MAF licensed for upstream abstraction (range 1–20%). No statistically significant overall difference in macrophyte assemblage diversity (number of taxa) or composition was detected between reference and non‐reference sites. When each non‐reference site was compared with those particular reference sites that it most resembled in non‐hydrological environmental features relevant to macrophyte assemblages, the similarity between observed and reference data was unrelated to the amount of upstream entitlement for abstraction. The lack of any evident impact on macrophyte assemblages was attributed mainly to the relatively small proportion of flow licensed for abstraction, the fact that the study sites did not dry completely, and the resilience of stream macrophytes to drought. However, the difficulty in distinguishing abstraction impacts from high background spatial variability in macrophyte assemblages may also have been influential. Copyright © 2008 John Wiley & Sons, Ltd.