The role of cracking clay soils in maintaining biodiversity in South Australia’s rangelands, and implications for sustainable management of arid zone landscapes

A project undertaken at the School of Natural and Built Environments at the University of South Australia and supervised by Sophie (Topa) Petit

The cracking clay soils that occur in the South Australian rangelands are characterised by deep cracks that may provide shelter for small native animals. We will identify animals and plants using cracks at various sites. By buffering environmental extremes (e.g. temperature), cracks are likely to provide shelter for a diversity of native animals, including invertebrates, reptiles, and mammals, as well as seeds and seedlings.

The Australian rangelands cover most of the continent; cracking clays are patchily present throughout arid parts of the rangelands. However, the role of cracking clays in maintaining rangeland biodiversity has not been quantified. Because cracking clays may be important for maintaining biodiversity, research to determine the nature of this role, including crack characteristics and shelter qualities, habitat value for small animals, and role in food provision and seed/seedling protection is warranted. Quantifying these properties will enable the development of management recommendations for arid zone landscapes with cracking clays.

If cracking clays are important for maintaining species diversity and abundance, then this role needs to be considered in relation to the impacts of common land uses, such as pastoralism. We will relate crack characteristics to shelter properties and species’ use, identify how the arid zone food web is influenced by cracking clays, compare productivity in terms of biodiversity and biomass between sites, and develop management recommendations that will apply to natural resource management organisations, private stakeholders, the pastoral and mining industries. We aim to determine the role of cracking clays in maintaining biodiversity in the South Australian rangelands. This project has implications for sustainable rangelands management and biodiversity conservation in the arid zone.