Oral Presentation Australian Freshwater Sciences Society Conference 2024

Impacts of short-term flow changes on macroinvertebrate communities in streams draining agricultural and uncleared catchments (112592)

Bridget White 1 , Sean Atkinson 2 , Belinda Robson 2 , Russell Death 3 , Leon Barmuta 1
  1. School of Natural Sciences, University of Tasmania, Hobart, Tasmania, Australia
  2. Centre for Sustainable Aquatic Ecosystems, Murdoch University, Murdoch, Western Australia, Australia
  3. River Research, Pohangina, New Zealand

Freshwater macroinvertebrate communities are altered by the press disturbance of upstream conversion to agriculture as well as pulse disturbances by temporary changes to flow. The diversity and redundancy of response traits should be key to understanding how chronic disturbances affect the capacity of communities to respond to pulses of changed flow. We experimentally tested how the ecosystem changes resulting from agricultural conversion affected the short-term responses of macroinvertebrate communities to flow changes using temporary weirs in each of eight streams in Tasmania spanning a range of catchment conversion using a before-after control-impact study design. As well as documenting changes in community structure, we also measured decomposition (using both leaves and cotton strips) and accumulation of algal biomass during and after flow change as proxies of the major ecosystem functions in these streams to provide a comprehensive picture of the different aspects of ecosystem recovery.