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Groundwater dependent wetlands in the South-East of South Australia face multiple threats associated with declining groundwater level and the interaction of this with climate change and increased risk of salinization. This project undertook a range of investigations involving satellite data analysis, field investigations and scenario modelling with a feature of the work being the different spatial scales of investigation undertaken. This provided insights into processes operating from wetland to regional scales.
Much of the work was based on the development of a conceptual hydro-salinity classification for wetland habitat that is applicable to wetlands of the South-East. The classification can be used to quantify and compare habitat diversity within and between wetlands. Common wetland plants were assigned to hydrological (plant functional group) and salinity tolerance classes, allowing these to be positioned within the hydro-salinity classification. This provided a parsimonious but powerful framework for modelling probable changes in wetland plant communities that would result for reduced water availability. Complementary modelling work was undertaken demonstrating the use of such an approach.
Remote sensing time series analysis over the period 1990–2013 provided a region-wide picture of changes in wetland inundation and greenness – a measure of vegetation vigour. Most wetlands across the South-East experienced reductions in both greenness and inundation during the period 2003/04 to 2006/07, which then recovered over the period up until 2011. From 2011 to the end of 2013 both measures of wetland condition again declined.
This project collected data from an extensive field sampling program across 12 wetlands and wetland complexes, allowing hydrological response models to be built and validated for the eight most common plant functional groups in the region.
Research through this project and concurrent hydrological work suggests an exciting future for predictive wetland science in the South-East. The opportunity to couple hydrological models, downscaled regional climate projections and spatial data with ecological response models opens an enormous range of possible investigations to support management questions. The hydro-salinity classification scheme provides a framework within which to pose, evaluate and answer questions relating to current and future wetland condition.
