Assessing the ecological values of rivers: an application of a multi-criteria approach to rivers of the South Coast Region, Western Australia

There is a growing awareness that in the light of increased threats, Australia’s freshwater ecosystems of highest value need to be protected. This implies that a consistent and comprehensive system for the classification of freshwater systems in terms of their ecological values is required for conservation planning. Despite earlier steps taken to develop appropriate methodologies for prioritising Australian waterways for protection, there is, as yet, no nationally agreed method for prioritising waterways in Australia based on their ecological values. Using the core criteria of naturalness, representativeness, diversity, rarity and special features, this paper describes the development of a framework of criteria, indicators and measures for the identification of high conservation value aquatic ecosystems, and trials this system by undertaking a comparative assessment of the ecological values of river systems in the South Coast region, Western Australia. A total of 33 river systems located in two aquatic bioregions were successfully ranked according to their ecological value, confirming that the development and implementation of a relatively simple system for assessing ecological values of Australian rivers shows promise, and that core criteria identified previously in the literature provide a good starting point for assessing ecological values of Australian aquatic ecosystems.