Elizabeth McLean

School of Plant Biology (M090) 
University of Western Australia
35 Stirling Highway
Crawley WA 6009
AUSTRALIA

telephone:  +61 8 6488 7923
fax:           +61 8 6488 7925
email:         mcleae02@stdent.uwa.edu.au

BSc (Hons), UWA (2002)

PhD Thesis:  Water use patterns of the riparian tree Melaleuca argentea in the Pilbara.

Supervisors: Dr Pauline Grierson (UWA), Dr Martha Ludwig (UWA), Professor Mark Adams (USyd)
Funding: ARC LP0776626 Rio Tinto Iron Ore, BHP Billiton Iron Ore
Commenced: October 2007

Surface and near surface water is a scarce resource in the semi-arid environment of the Pilbara. Larger trees and associated understorey vegetation are able to survive only along riparian  networks of often ephemeral streams (riparian communities). I am investigating the water use characteristics of Melaleuca argentea, a tree species that is common in riparian zones across Northern Australia.

Water availability in riparian zones of most streams in the north-west is highly variable, both spatially and temporally. Trees have access to a number of water sources - groundwater, creek water and soil moisture. Rainfall in the Pilbara is highly episodic, so trees may be experience periods of drought, interspersed with occasional flooding. In addition, the hydrology of some areas has been altered by mining activities such as groundwater drawdown, and discharge of excess water into creeklines, which in some cases has severely impacted the health of riparian trees. My research examines the tolerance of M. argentea to drought and flooding, and the ways in which riparian trees regulate water uptake, which will help define ecological water requirements.

Objectives

• Assess the drought and flooding tolerance of M. argentea, and tree responses to changes in water regime.

• Characterise the recruitment of M. argentea seedlings and saplings along water availability gradients.

• Examine the importance of different water sources (groundwater, creek and soil water) to survival of M. argentea and the functional differences between roots accessing each water source.