Detecting effects of environmental water allocations in wetlands of the Murray–Darling Basin, Australia

Abstract

River regulation has significantly altered the hydrology and ecology of floodplain wetlands throughout the Murray–Darling Basin, Australia. Management plans proposed for rivers in the Murray – Darling Basin incorporate 'environmental water allocations' (EWAs) designed to redress some of the damage caused by regulation, via partial restoration of the natural hydrological regime that used to be experienced by associated floodplain wetlands. Monitoring and scientifically rigorous adaptive management practices are the key to the long-term success of EWAs, and successful monitoring relies on the well-informed selection of a variety of hydrologically sensitive indicators. In this paper, we recommend a range of physical, chemical and biological indicators for use for monitoring change in wetland health in response to EWAs. Physical and chemical variables suggested include wetland depth, wetland area and salinity. Aquatic macrophytes and macroinvertebrates are recommended as the primary biological indicators for monitoring change within the Murray–Darling Basin, although the indicator potential of macroinvertebrates still has to be confirmed by planned and ongoing research. Information is also presented for a variety of other components of wetland ecosystems, including biofilms, zooplankton, birds, fish, mammals, reptiles, amphibians and fringing vegetation. Our current knowledge of the relationships of these variables with wetland hydrology and ecosystem health is relatively limited. Further research is required to investigate the nature of these relationships and determine the utility of these parameters as indicators within wetlands of the Murray – Darling Basin.