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Pilbara mine sites a tough challenge Dr David Merritt Research Scientist Dr Todd Erickson Research Scientist
T
he Pilbara is one of the most spectacular bioregions of Western Australia. The expansive grasslands dotted with imposing mesas are intersected by the rivers and flood plains of the Fortescue Marsh. These visions typify the Australian outback with endless blue skies contrasting the red, rocky soils. This ancient landscape is floristically diverse for a semiarid region, supporting around 1800 native plant species. The region is also a bonanza for the Australian economy as one of the world’s primary sources of iron ore and other minerals. One of the consequences of mining is thousands of square kilometres of disturbance and degradation. Kings Park Science has a long history of research in this region to support ecological restoration, forming longrunning partnerships with industry including BHP and Rio Tinto. A primary focus has been the development of seed technologies to improve our capability to re-establish biodiverse plant communities on the large scale necessary to repair mining footprints. A starting point is seed biology, particularly the requirements for sourcing large amounts of seeds, storing seeds and developing the know-how to germinate them. One highlight of this research was the release of the Pilbara Seed Atlas and Field Guide in April 2016.
This photographic guide to more than 100 species synthesises over a decade of research into their seed biology and propagation for restoration. Knowing how to store and germinate the seeds is just the start. We must understand how seeds behave in the natural environment to successfully restore vegetation and use this insight to increase the chances of seedling establishment. Over the past seven years a major program of field trials has been conducted as part of a research partnership with BHP. In 2014, under the Restoration Seed Bank Initiative, a Controlled Environment Facility (CEF) was built at BHP’s Mt Whaleback mine site. This facility houses 32 experimental plots that hold various types of reconstructed soils typically encountered following mining operations. Different rainfall scenarios can be simulated through irrigation of the plots, providing the ability to field-proof seed treatments developed in the laboratory and a stepping-stone to full-scale field trials on mine waste dumps. Seeds are the starting point to reintroduce vegetation, but they need to be placed into soils that can support plant growth. Mining significantly alters the topography of the landscape and removes the plants, animals and topsoil during the resource extraction process. The waste materials are typically formed into vast novel landforms that become the new substrates for restored vegetation, yet are foreign to the local seeds and plants.
Drylands such as the Pilbara are important regions of the world, covering almost half the Earth’s land surface. Photo: Alexandra Rouillard
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For People & Plants | Special Issue | Spring 2021
