Poster Presentation Australian Society for Limnology Congress 2013

Understanding the impacts of water extraction on ecosystem structure and function in remnant river pools. (#217)

Mathew Birch 1 , Darren Ryder 1 , Ivor Growns 2
  1. University of New England, Armidale, NSW, Australia
  2. NSW Office of Water, Armidale, NSW, Australia

Flow variation is a common feature among lotic aquatic systems. The known ecological effects of changing flow regimes vary, depending upon landscape, catchment and habitat characteristics. In upland intermittent streams the effects of low flow periods may be exacerbated by water extraction for human needs. The importance of these impacts magnifies when low flow refugia, threatened species (such as the Purple-spotted Gudgeon, Mogurnda adspersa) and water extraction points are found in the same place. 

Water managers need to understand how biogeographical, ecological and physical factors interact to determine the resilience and resistance of wetland pool ecosystems during low flow and no flow conditions in order to sustain ecological condition and extractive needs in variable settings.

This study aims to develop an understanding of the factors underpinning ecosystem structure and function of wetland pools in upland intermittent streams under varying conditions. A further aim is to produce conceptual models of categorised upland refugia demonstrating the major biogeographical, physical and ecological factors driving variation in trophic pathways, food sources and fish population dynamics. Outcomes from the project will lead to principles to guide cease-to-pump management rules in river systems.

The proposed methods will assess medium-term variation in fish and macroinvertebrate community structure, trophic pathways and landscape factors over changing flow and among refugia with varied characteristics at catchment and macro-habitat scales. Experimental in-situ flow manipulation will be utilised to assess short-term responses to water extraction in Tenterfield Creek.