Much of the focus of wetland restoration in the Murray floodplain has been underpinned by the focus on river flows as the cause of system degradation. A longer term view of ecosystem condition inferred from sediment cores identifies the flux of sediments, salts and nutrients as significant supplementary drivers of wetland change. There is clear evidence for increasing sedimentation rates and salinization from early after European settlement. The regulation of the river increased the extent of change with the fossil diatom assemblages in all of the 50+ sites examined reflecting a degraded state relative to the ‘natural’ baseline. Sedimentation rates often exceed 1 cm/yr and this high flux in fine sediments has increased the turbidity of the most sites. There is evidence for the widespread replacement of submerged macrophytes with phytoplankton consistent with stable state change models. A spatial analysis of paleolimnological records has enabled the identification of a wetland typology of vulnerability to this shift with middle reach wetlands most at risk. Investment in the mitigation of water quality decline would supplement the benefits that may accrue from the provision of environmental water.
Gell, P. & Reid, M. (2016). Muddied Waters: the case for mitigating sediment and nutrient flux to optimise restoration response. Frontiers in Ecology and Evolution, doi: 3389/fevo.2016.00016
Gell, P. & Reid, M. (2014) Assessing change in floodplain wetland condition in the Murray Darling Basin. The Anthropocene, 8: 39-45.