Thursday, May 29, 2008 - 1:30 PM
577

Hydroperiodicity, catchment controls, extinction sequences, and recolonization dynamics: Towards a conceptual model of processes affecting aquatic invertebrate community composition in intermittent streams

Andrew J. Boulton, Ecosystem Management, University of New England, Elm Ave, Armidale, Australia and Paul J. Wood, Department of Geography, Loughborough University, Loughborough.

Duration of the wet-dry period (hydroperiodicity) is considered the primary driver influencing aquatic invertebrate community composition in intermittent streams worldwide.  Aspects of timing, frequency, rate and intensity of drying and re-wetting are other relevant hydrological features as well as the hydrogeology of associated shallow aquifers in some areas.  Superimposed on this hydrological and hydrogeological template are catchment controls (e.g. drainage patterns, land-use, vegetation), frequently modified by humans.  These controls interact with channel and floodplain geomorphology to govern the types of refugia available to invertebrates during drawdown and water loss.  Biological interactions such as predation and competition intensify during drying but the relationship between the effects of these with physiological impacts of deteriorating water quality is unclear.  Nonetheless, the extinction sequence and availability of refuges governs the composition and abundance of recolonists when flow resumes.  We integrate our research data from diverse intermittent streams in the UK, US and Australia with world literature to derive a conceptual model of processes affecting invertebrate community composition over both annual and mult-annual temporal resolutions.  This model helps interpret apparent discrepancies in response to hydroperiod in different streams as well as predict changes in invertebrate composition when flow patterns, channel features, and refuge availability are altered by human activities.


Web Page: intermittent streams, aquatic invertebrates, conceptual model

See more of Special Session - Intermittent Rivers: Global Phenomena and Unexplored Riverscapes I
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See more of The Nabs 56th Annual Meeting (25-28 May, 2008)