Lateral and variable connectivity between rivers and wetlands influences the mosaic of habitats that occur on floodplains. Pulses of flood induced connectivity are important for the exchange of carbon and nutrients, primary and secondary production and movement of biota. In northern Australia, flooding and wetland connectivity occurs annually, coinciding with the onset of the monsoonal season. Climate related changes and water resource development is likely to modify the frequency of connectivity between rivers and associated floodplain wetlands.
In this study, Water Observations from Space was used to identify the location of wetlands on riverine floodplains in northern Australia based on pixels that indicated the presence of water that persisted for more than 50 days. Hydrodynamic modelling of small, medium and large floods was used to calculate hydrological flow metrics related to wetland connectivity. Using these metrics, wetlands were classified into three groups (i) no connection, (ii) wetlands with intermittent periods of connectivity, and (iii) wetlands with a single persistent connection event. Changes in connectivity was then quantified against either a wetting or drying climate scenario in combination with water resource development in the catchment.
Analysis will explore changes under a drying climate and water resource development. We also explore the the proportion of wetlands that remain unconnected during flood events and the corresponding decrease in the proportion of wetlands with intermittent connectivity and persistent connectivity. The talk will discuss implications, such as the reduction in the effective size of the floodplains and the ecological consequences of potential reduced connectivity, changes in ecosystem state and loss of biodiversity.