T.G.H. STOCKWELL¹, R.T. ANDISON¹, A.J. ASH², J.A. BELLAMY³ and R.M. DYER⁴

¹Department of Primary Industry and Fisheries, Katherine, NT, Australia
² Division of Tropical Crops and Pastures, CSIRO, Townsville and ³ Brisbane, Queensland, Australia

Abstract

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