Ecology and conservation of a nomad: a case study using the Australian Bustard

A project undertaken at The School of Earth and Environmental Science, The University of Adelaide and co-supervised by Mark Ziembicki, David Paton and John Woinarski (Biodiversity Unit, NT Department of Infrastructure, Planning and Environment)

Australia’s highly variable and erratic climate has resulted in a flora and fauna that is uniquely adapted to extremes in environmental conditions. Such adaptations are highlighted by the birds of Australia’s arid and semi-arid regions which, in response to erratic rainfall and periods of prolonged drought, undergo large population fluctuations and make large-scale nomadic movements tracking favourable conditions opportunistically across the landscape. The status, distribution and movements of nomadic birds are inherently difficult to assess and poorly understood. These characteristics complicate management and conservation of such species because their conservation depends on understanding distribution and movement patterns and ensuring the maintenance of suitable habitat in geographically distant and disconnected locations over broad time periods. Traditional conservation reserves do not adequately cater for nomads because of their small sizes and the readiness of nomads to move out of reserves as their suitability changes through time.

Although nomadic movements have been regarded as unpredictable there may be underlying patterns to movements that we do not understand because of studies at inadequate scales. If bird movements are deterministic and birds ‘know’ to some degree where they are going at particular times then it may be possible to predict where the locations of these areas are. These areas can then be targeted for protection at key times, for example, feral predator control or hunting restrictions in favourable breeding areas or refuge areas required during drought. Such knowledge would effectively facilitate predictive or pre-emptive conservation planning (by developing mobile or shifting conservation zones in time and space), thereby overcoming the limitations of current static reserve design and conservation strategies.

The Australian Bustard is representative of a suite of ground nesting, highly mobile birds that have undergone significant declines in Australia’s rangelands. It responds readily to the marked variability in habitats arising from rainfall variations, and its occurrence and abundance is likely to be related to fire management, grazing intensity, agricultural development and other variations in the landscape. Using the bustard as a model species, this study employs latest developments in satellite tracking and spatial information systems technology to develop techniques to help predict the poorly understood movements and distributions of nomadic terrestrial birds in relation to landscape conditions. This should lead to better targeted conservation measures, and the possible use of nomads as indicators of habitat condition.

Data from satellite tracking of individual bustards, together with that from aerial surveys, bird atlases and mail surveys, are being overlaid on continental rainfall patterns, land condition indices, fire history patterns and management regimes to establish a picture of the bustard’s movements and distribution over time. Further data should point to the strategies determining the initiation, orientation and termination of nomadic movements. Complementing this broad scale study is a detailed investigation of the species ecology at two contrasting sites in the tropical savannas of northern Australia. Additionally, the project works in collaboration with Aboriginal communities who have an extensive knowledge of the species distribution and ecology and harvest the bustard for food. By incorporating a broad, holistic approach the study aims to contribute to the management and conservation of this declining species and other nomadic birds at local, regional and national scales.