Assessing habitat services in semiarid floodplain wetlands during droughts

Abstract:

Vegetation in floodplain wetlands provide habitat services for diverse fauna. Extensive work has been done which reflects on the importance of these wetlands as refugia for migratory birds and fish during dry periods. The establishment and maintenance of the vegetation are dependent on water availability and the water regime. In the floodplains of semiarid Australia, there is a complex interaction between the highly variable flows and the low gradient topography, which then drive the flood patterns and allows for the formation of extensive wetlands. After drought periods, vegetation has shown a high resilience for recovery through diverse dormancy mechanisms, but the condition of the vegetation during extended drought periods can be significantly deteriorated and thus reduce associated habitat services. Water sharing plans developed by regulatory authorities include environmental water deliveries to wetland sites with the aim of producing the best outcomes for vegetation and other ecological objectives such as waterbird breeding events. However, the definition of water releases and monitoring of vegetation outcomes can be aided by the use of realistic prediction tools that would allow the assessment of vegetation condition over time. We have developed an eco-hydraulic model that integrates hydrodynamic simulations with vegetation response functions to provide estimates of the expected state of the vegetation and we apply this model to an iconic wetland system better known as the Macquarie Marshes. We analyze the impacts that recent droughts have had on the vegetation of the site and habitat services.