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The ecology of rivers with contrasting flow regimes: identifying indicators for setting environmental flows

Citation

Warfe, DM and Hardie, SA and Uytendaal, AR and Bobbi, CJ and Barmuta, LA, The ecology of rivers with contrasting flow regimes: identifying indicators for setting environmental flows, Freshwater Biology, 59, (10) pp. 2064-2080. ISSN 0046-5070 (2014) [Refereed Article]

Copyright Statement

Copyright 2014 State of Tasmania

DOI: doi:10.1111/fwb.12407

Abstract

  1. The scientific basis for setting environmental flows is still hampered by our incomplete understanding of flow–ecology relationships and how river ecology varies with flow regime.
  2. We conducted a study of six rivers in Tasmania (Australia), three perennial and three intermittent, measuring a range of abiotic, biotic and ecosystem process attributes over 2 years. Our intentions were to identify: (i) whether they had an ecology characteristic of their flow regime and (ii) whether certain ecological attributes were more responsive to flow regime than others, and therefore represented candidate indicators (for environmental flows or flow alteration) specific to each flow regime.
  3. Only a few abiotic variables showed any relationship with flow regime: banks were higher, pools shallower and sediments finer in perennial rivers, and water temperature was generally lower in perennial rivers. Although rarely measured, we found that productivity and net ecosystem metabolism were strongly related to flow regime, whereas food chain length did not vary between perennial and intermittent rivers. Multivariate, rather than univariate, metrics of biotic assemblages were more effective at distinguishing perennial and intermittent flow regimes, and this was consistent among riparian and instream vegetation, biofilm and macroinvertebrate assemblages. In contrast to expectations from the literature, fish assemblages were not strong indicators of flow regime, largely due to the relatively low diversity and abundance of the Tasmanian fish fauna.
  4. Our findings demonstrate that rivers with different flow regimes can support a distinctive ecology, and conventional metrics of ecological character may not be the most sensitive to flow regime. We provide a set of ecological attributes that can: (i) support extrapolation of flow–ecology relationships across rivers to regional scales, (ii) provide benchmarks for environmental flow and flow restoration objectives, (iii) indicate alterations to natural or existing flow regimes and (iv) be used to monitor and evaluate flow management actions.

Item Details

Item Type:Refereed Article
Keywords:flow restoration, flow variability, flow-ecology relationships, monitoring and evaluation, river management
Research Division:Biological Sciences
Research Group:Ecology
Research Field:Freshwater Ecology
Objective Division:Environment
Objective Group:Ecosystem Assessment and Management
Objective Field:Ecosystem Assessment and Management of Fresh, Ground and Surface Water Environments
Author:Warfe, DM (Dr Danielle Warfe)
Author:Hardie, SA (Dr Scott Hardie)
Author:Barmuta, LA (Associate Professor Leon Barmuta)
ID Code:93649
Year Published:2014
Web of Science® Times Cited:6
Deposited By:Zoology
Deposited On:2014-08-12
Last Modified:2017-10-31
Downloads:0

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