Macroinvertebrate regionalisation for use in the management of aquatic ecosystems in Victoria, Australia

The development of a broader, more holistic approach to aquatic ecosystem management has been called for in recent years. Physical and chemical objectives alone are no longer considered sufficient for the protection of aquatic ecosystems and should be supplemented with biological objectives. The ubiquitous and sedentary nature of macroinvertebrates, combined with their measurable response to environmental conditions, favour their use as important indicators in environmental policies. To establish biological objectives, there is a need for a regional framework to limit the variability between ecosystems. Past studies have demonstrated that an a posteriori regionalisation approach may be more useful than an a priori approach in explaining single component (e.g. macroinvertebrates) patterns across ecosystems. This is particularly important as aquatic resource management agencies often focus on one or two components of the ecosystem to assess environmental health. This study uses an a posteriori method to delineate and describe biological regions based on edge and riffle macroinvertebrate data. The regionalisation will provide a framework for setting biological objectives, based on the range of reference conditions measured within each separate region. The objectives will include regional checklists for taxa and biotic indices. Predictive modelling in the style of RIVPACS or AUSRIVAS will also be used within each region to develop objectives, incorporating local, regional and systematic features as predictor variables.