Reducing the Vulnerability of Societies to Water Related Risks at the Basin Scale (Proceedings of the third International Symposium on Integrated Water Resources Management, Bochum, Germany, September 2006). IAHS Publ. 317, 2007 72–76.

The relationship between native vegetation and in-stream salinity: an Australian case study

VINCENT LAWRENCE VERSACE¹, DANIEL IERODIACONOU¹, FRANK STAGNITTI¹, ANDREW JOHN HAMILTON¹, M. TODD WALTER² & MARC LEBLANC³

1 School of Life and Environmental Sciences, Deakin University, PO Box 423, Warrnambool, Victoria 3280, Australia

vlv@deakin.edu.au

2 Department of Biological and Environmental Engineering, Cornell University, New York 14853-5701, USA

3 School of Geosciences, Monash University, Clayton, Victoria 3800, Australia

Abstract The Glenelg-Hopkins area is a large regional watershed (2.6 million ha) in southwest Victoria that has been extensively cleared for agriculture. In-stream electrical conductivity (EC) in relation to remnant native vegetation is examined from the headwaters to the upper extent of the estuary of the Glenelg River. Five water quality gauging stations were selected. Their contributing subcatchments represent a continuum of disturbance. Proportions of native vegetation ranged from ~100% at the headwaters of the river to ~30% at the furthest downstream gauge station. The relationship between remnant vegetation and in-stream EC was examined using aggregated and non-aggregated land use statistics over a period of 22 years from three land use maps. Increased proportions of native vegetation were significantly negatively correlated with in-stream EC and were consistent across all scenarios investigated.

Key words dryland salinity, GIS, land cover, land degradation, land use, vegetation