Other information:
Does flow modification cause geomorphological and ecological response in rivers? A literature review from an Australian perspective
By: Dr Natalie Lloyd, Assoc. Prof. Gerry Quinn, Assoc. Prof. Martin Thoms, Prof. Angela Arthington, Dr Ben Gawne, Dr Paul Humphries, Assoc. Prof. Keith Walker
This report reviews a subset of refereed and unrefereed Australian and international literature to assess the evidence for ecological responses to flow modifications in rivers. The studies we examined produce overwhelming evidence that both river ecology and river geomorphology change in response to flow modification. Specifically,
- 87% of the studies reviewed demonstrate an ecological and/or geomorphological effect(s) of flow modification
- 83% of variables demonstrate an ecological and/or geomorphological effect(s) of flow modification
- all the studies in which the change to flow was measured or could be determined from gauge data (n = 30) demonstrated an ecological and/or geomorphological effect(s) of flow modification
- all of the 9 studies investigating geomorphological responses to flow modification recorded geomorphological changes, and
- 56 of 65 (86%) studies investigating ecological responses to flow modification recorded ecological changes.
Despite the unequivocal evidence for ecological responses to flow change, the relationship between these two measures was not simple. Small flow changes could produce large ecological responses and no simple thresholds were detected. However, only a few studies provided quantified information on flow change and ecological response that could be compared between studies and included in analyses of relationships and thresholds. A larger dataset is required before the nature of the relationship between flow change and ecological response can be properly described and used for prediction.
Clear directions for future research are highlighted from this review:
1. To be able to compare regions and river types, floodplains and wetlands, we need a consistent characterisation of flow change.
2. Much of the data generated in the studies reviewed needs to be re-analysed, to provide robust and comparable measures of ecological change.
To improve our understanding of the geographic and time scales of hydrological and ecological changes we will need a better conceptual framework for dealing with mismatches of scale in the various analyses and interpretations of flow–ecology relationships.
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