Water-based assets of the Murray–Darling Basin and their ecological condition

This chapter presents an overview of the aquatic ecosystems of the Murray–Darling Basin (MDB). Ecosystem types within the Basin are diverse, ranging from small upland streams to the coastal estuary at the river mouth. The vast floodplains and associated rivers and wetlands are the most iconic habitats of the MDB, together with rich communities of plants, birds, fish, and other organisms. The diversity of ecosystem types are summarised, as are each of the major biotic groups making up the Basins’ flora and fauna. The links to hydrology, and, in particular, the role of floods and droughts in the life cycle of these various organisms. Land clearing and flow alteration associated with agriculture and water resource development have had a significant impact on the condition of aquatic ecosystems in the MDB, and climate change is now also emerging as a major threat. These impacts are discussed, together with a brief overview of current efforts to mitigate them and to restore the health of aquatic ecosystems, particularly the more heavily impacted lowland areas and the coastal estuary.