WIRE- Soil water repellence in biodiverse semi arid environments: new insights and implications for ecological restoration

Abstract

Soil water repellency (SWR) can have a critical effect on the restoration of disturbed ecosystems causing poor plant establishment and promoting erosion processes. Although SWR has been reported in most continents f the world for different soil types, climate conditions and land uses, there are still many research gaps in the knowledge of its causes and controlling factors (Doerr et al.,2000; Jordan et al., 2013), particularly in Mediterranean arid semi arid environments which are largely affected by this phenomenon. The WIRE project aims to investigate SWR in soils under different vegetation types of dominant biodiverse ecosystems of Western Australia (WA), e.g. hummock grasslands and Banksia woodlands, as well as characterizing organic compounds that induce hydrophobicity in these soils. Banksia woodlands (BW) are of particular interest in this project. These re iconic ecosystems of WA composed by an overstorey dominated by Proteaceae that are threatened by sand mining activities and urban expansion. Conservation and restoration of these woodlands are critical but despite considerable efforts to restore these areas, the success of current rehabilitation programs is poor due to the high sensitivity of the ecosystem to drought stress and the disruption of water dynamics in mature BW soils that result in low seedling survival rates (5-30%). The main objectives of this collaborative research are: i) to identify SWR intensity and severity under different vegetation types and evaluate controlling factors in both hummock grasslands and BW (ii) to characterize hydrophobic compounds in soils using analytical pyrolysis techniques and iii) to investigate the impact of SWR on water economy in relation with soil functioning and plant strategies for water uptake in pristine BW.