Can conservation assessment criteria developed for terrestrial systems be applied to riverine systems?

Australia's aquatic ecosystems are of outstanding diversity and interest on a world scale. As one of the world's driest continents, its water resources are under growing pressure, yet there are no systematic conservation efforts. Any moves towards aquatic biodiversity conservation must be pursued within appropriate scientific, policy, and management contexts. A key starting point is the articulation of aquatic conservation values. Concepts and criteria for biodiversity conservation are well established in the conservation of terrestrial ecosystems in Australia. They are often framed within legislation or derived through policy and practice. If freshwater biodiversity is to be conserved, then conservation criteria and methods of assessment need be integrated with possible mechanisms for protection. So it is useful to examine whether the criteria and thresholds applied to terrestrial systems are valid and appropriate for freshwater ecosystems. Two key questions are discussed: are commonly applied conservation criteria appropriate and adequate for aquatic ecosystems? and, is it feasible to apply criteria used in terrestrial systems to aquatic systems? The discussion is informed by evidence from two perspectives: a survey of views of river scientists and managers, and analysis of field studies of river conservation assessments in Australia. The data suggest that while the basic concepts that define biodiversity value can be applied to aquatic systems, difficulties are apparent in applying and interpreting the thresholds and decision rules used for terrestrial systems. In addition, the survey of scientists and managers in Australia showed that landscape scale values and riverine functions should be incorporated in the assessment and protection of riverine systems. The analysis concludes that conservation of freshwater biodiversity in Australia needs to be founded upon national legislation and policies for biodiversity conservation alongside conservation of terrestrial systems. However, different approaches to defining and assessing biodiversity value of freshwater ecosystems will need to be explored and specified.