Enigmatic impacts of mining and linear infrastructure development in Australia’s Great Western Woodlands

Background and aims

Extensive developments, such as mining, and oil and gas extraction, in relatively intact landscapes, can have numerous ecological impacts that affect the ecosystems within which they are situated. These impacts are often poorly understood and even more poorly accounted for in impact evaluations, biodiversity offsets, and regional conservation or land-use plans that are intended to mitigate impacts and protect the ecological assets and natural values of the landscapes in question.

This research is directed at improving our ability to conceptualise and account for these ‘enigmatic’ impacts in order to improve the decisions that we make in planning, approving, managing and offsetting extensive developments in relatively intact landscapes, with a focus on mitigating the ecological effects of mining and exploration Western Australia’s Great Western Woodland.

The Great Western Woodlands

The Great Western Woodlands is an internationally significant area of great biological richness, owing partly to its 250 million year continuous biological heritage, its location at the interzone between the moist southwest corner of Australia and the arid interior, and its relative intactness. At 16 million hectares, the Great Western Woodlands is larger than England and represents the largest remaining temperate woodland on earth. The region comprises a mosaic of woodland; shrubland; mallee; casuarina and melaleuca thickets; rocky outcrops; halophytic vegetation; salt lakes; and banded ironstone formations, and is the driest place in which such tall woodlands grow. The area is home to almost one third of Australia’s eucalypt taxa and well over 3000 flowering plant species (more than twice the number that occur in the whole of the UK), as well as many species that occur nowhere else in the world.

The Great Western Woodlands is also a very rich and productive mineral province, with 134 operating mines and 119,303 ‘abandoned mines’ registered within its boundaries, as well as more than 5000 current mineral tenements covering more than 60% of the region. Mining in the region mainly targets gold, nickel and iron ore, but commercial quantities of silver, copper, cobalt, gypsum, salt, and construction materials are also extracted.

The Great Western Woodlands

This research consisted of:

1. A review of ecological impacts that are frequently overlooked in impact evaluations but that continue to cause ecological loss and degradation, with a proposed framework for conceptualising and addressing these issues published in the highly-ranked journal Trends in Ecology and Evolution.
2. A spatial analysis of ground disturbance in the Great Western Woodlands using GIS and remote sensing to identify and characterise cumulative impacts and areas within disturbance buffers, as well as associations between disturbed areas and disturbance types, land tenure, tenement history, and selected environmental values.  A key outcome of this work has been the identification of roads, tracks and other linear infrastructure corridors as major components of the disturbance regime, despite their impacts being particularly poorly understood (the following sections go some way toward addressing this knowledge gap).
3. An observational field investigation using motion-sensor cameras and spoor (scats, prints, etc.) surveys to understand the effects of roads and tracks on predator activity within relatively intact landscapes.
4. A survey of ephemeral drainage lines, erosional features, and water pooling features, and their association with linear infrastructure corridors to characterise and quantify the type and extent of impacts of linear infrastructure on water movement across landscapes.

Prudent strategic assessment and comprehensive mitigation that accounts for all impacts — even enigmatic ones — could provide improved environmental and land-use planning outcomes while potentially benefiting development proponents by providing greater upfront guidance and certainty of access to specified areas, and enhancing their ‘social licence to operate’.

This research contributes to efforts to conserve in perpetuity a relatively intact ecosystem that dates back to Gondwanan times and is internationally significant for its biodiversity and wilderness values. It is also an area cherished by its traditional owners in the cultural and spiritual connections they have with the land, and by many others who prize the region and its unique landscape.

This PhD project was supervised by Professor Richard Hobbs (University of Western Australia), Dr Suzanne Prober (CSIRO), Professor Hugh Possingham (University of Queensland), Dr Leonie Valentine and Dr Kerrie Wilson (University of Queensland), and has been supported by the UWA Gledden Postgraduate Research Scholarship, the Australian Research Council’s Centre of Excellence for Environmental Decisions, the National Environmental Research Program Environmental Decisions Hub, and The Wilderness Society. It runs in association with the Terrestrial Environmental Research Network’s Great Western Woodlands Supersite and the work of GondwanaLink and Pew Trusts.

Keren’s full PhD thesis is available at: http://research-repository.uwa.edu.au/files/10146368/THESIS_DOCTOR_OF_PHILOSOPHY_RAITER_Keren_Gila_2016.pdf