Spotlight on Grazing
An early love of water, sailing and riverside holidays has led to professional interest in how hydrology shapes our landscape and the life it supports for CSIRO scientist Scott Wilkinson.
Scott is leading a project to investigate relationships between grazing practices, land cover and soil condition and erosion rates for key land types in the Burdekin and Fitzroy basins.
On case study sites where the ground cover ranges from high, medium or low, Scott and his team will look at the effect of management practices on property cover. With this information, they hope to estimate what the landscape-scale impacts on erosion would be of future changes to grazing practices and the likely outcomes of changing grazing practices in terms of pasture productivity and beef production.
For end-users in the beef industry, this will help build capacity to interpret management tools for indicating productivity and erosion resulting from grazing practices and for identifying priorities for practice change. With livestock grazing and cropping estimated to have increased fine sediment delivery to the Great Barrier Reef more than five-fold, reducing erosion is a priority for coastal managers.
Scott says that about 75 per cent of fine sediment is derived from grazing lands, where removal of vegetation cover, particularly during drier than average years, leaves the soil exposed to erosion.
"Prolonged low cover levels can cause degradation of pastures and soil health, reducing productivity. Previous studies have developed understanding of linkages between grazing practices, vegetation cover, runoff and erosion at site scales. This project takes that understanding to landscape scale," he explains.
"We use the variation in management practices between grazing properties to investigate the potential for practice changes, such as those funded under Reef Rescue, to influence the vegetation cover, land condition, soil erosion and productivity outcomes."
After a short engineering career, Scott says he was lucky enough to study fluvial sediment transport in the CRC for Catchment Hydrology.
"The reef catchments are a great place to work because the hydrological cycle here is energetic in Australian and world terms.
"Maybe the reef catchments are like 'custodians' of this massive coastal ecosystem – a little like a child with parents, the reef wouldn't be there without the continent but at the same time the reef is vulnerable and can only reach its best with good care."
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