Saline Ecosystems Feel the Squeeze From Increasing Salinity

Cant, L. Belinda Monash University, Clayton, Vic, Australia

Secondary salinisation poses a serious threat to terrestrial and freshwater ecosystems and water resources in arid areas of the world where land has been cleared of perennial deep-rooted vegetation causing saline water tables to rise. Wetlands are likely to be one of the first ecosystems to come into contact with saline water tables because they are low lying topographically. A survey of south-eastern Australia wetlands as part of this study supports this hypothesis wherein a mosaic of wetlands from fresh (<3 g/L salinity) to hyper saline (>35 and up to 200 g/L salinity) were described. The primary aim of the study was to determine changes in structure and function of wetland ecosystems across this landscape in response to variation in salinity. There was strong evidence that higher levels of salinity were associated with decreases in taxonomic diversity. Salinisation, in effect, manipulated biodiversity in such a manner as to make these ideal model systems to describe the relationship between biodiversity and ecosystem function. This could be studied at the scale at which natural communities exist; something largely lacking from biodiversity-ecosystem function research until now. Preliminary results indicate in systems with very high algal diversity there was a significant reductions in production but there was no difference between systems with moderate and low diversity.