Wetlands in drylands: the case in Australia

Wetlands in drylands (WIDS) typically have a negative annual water balance and provide essential biophysical habitats and ecosystem services in moisture-limited landscapes. WIDS are also inherently dynamic systems, since the form and functioning of rivers and wetlands change over time in response to extrinsic controls such as climate, hydrology, and human activities, and intrinsic factors such as sedimentation, erosion, and ecological succession. WIDS have irregular flood, drought and fire regimes that create mosaic-like aquatic ecosystems that often defy simple approaches to conservation and management. For example, changes in the location, extent and integrity of channels in wetlands can lead to significant changes in inundation, aquatic ecosystem responses to flooding, and to flow-on effects for biota, habitats and agricultural productivity. This is certainly the case in Australia, which has rivers and wetlands with some of the most variable hydrological regimes on Earth, that are also heavily relied upon for cultural and ecosystem services. Australia has 906 wetlands in the Directory of Important Wetlands in Australia (DIWA) Spatial Database, of which 65 are also listed under the Ramsar Convention. Approximately 52 % of these DIWA-listed wetlands occur in the drylands (interior) of Australia, many of which are connected to rivers in the Murray-Darling Basin. Australia is moving towards the long-term conservation, management and sustainable use of WIDS through the development of strategies tailored towards holistic and adaptive management of wetlands. Adaptive environmental watering and wetland management plans are being implemented state-by-state in Australia, while broader plans (e.g. Murray-Darling Basin Plan, finalised in 2012) provide a coordinated approach to water use between states. Such plans also set sustainable limits on extraction of surface water and groundwater and support investments and decision-making around water for the environment and water-efficient infrastructure. Although knowledge of the external controls, internal processes, and anthropogenic pressures on and requirements of WIDS is ever-growing, there is still a pressing need for integrated, multidisciplinary research and management to address key threats, thresholds of change, and future outcomes in these dynamic systems.