STATE AND TRANSITION MODELS FOR RANGELANDS .9. DEVELOPMENT OF STATE AND TRANSITION MODELS FOR PASTORAL MANAGEMENT OF THE GOLDEN BEARD GRASSAND LIMESTONE GRASS PASTURE LANDS OF NW AUSTRALIA

This paper describes the development of state and transition models fo r pastoral management of the golden beard grass (Chrysopogon fallaw) a nd limestone grass (Enneapogon spp.) pasture lands in the north-west o f Australia. The models were developed with the specific aims of: desc ribing the effects of management and seasonal conditions on botanical composition; providing a practical and effective tool to enhance manag ement of the pasture types for grazing; and providing a tool to enhanc e communication of range management practices and principles between p roducers, extension officers and research workers. Vegetation change i n both pasture systems was found to be driven by seasonal conditions, degree of utilisation and frequency of fire. The golden beard grass mo del was well received by an industry group in terms of its ability to describe the pasture system as presented by the authors. However, prol onged discussion ensued on the accuracy of the model, particularly in terms of the role of fire. The model provided a useful tool for collat ing and representing accumulated knowledge and opinion. As a process, it imposed a logical structure which tested the validity of opinion an d anecdotal evidence. It also provided a useful method for identifying where changes in states could not be easily or reliably identified.