REMA - A NEUTRAL MODEL TO REVEAL PATTERNS AND PROCESSES OF COVER CHANGE IN WOODED RANGELANDS

Remote sensing applications used for resource assessment often lack th e capacity to test image data against predictions. This article descri bes remote environment and management assessment (REMA), a new method for the interpretation of rangeland plant cover change, which uses Lan dsat MSS data and neutral predictions. REMA has been designed to provi de a generalized and testable method to assess herbivore impact on pot ential forage productiveness, even when a plant cover is heterogeneous ly distributed. In this article, models are constructed to interpret p atterns and processes of cover change within paddocks exposed to alter nating periods of plant cover increase and decline. Relative cover cha nges along distance from water point axes are derived to standardize a nd reveal gradients of cover change and cover resistance to drought. B y testing cover changes against neutral predictions, insights are gain ed into the association between grazing processes, geomorphology, and climatic conditions. Four MSS images of two sheep-grazed paddocks from wooded rangelands in eastern Australia are used to demonstrate that i ncreasing and decreasing linear cover change gradients, and contrastin g forage resistances to drought, can be found and assessed. The patter ns and levels of cover change due to grazing were found to be differen t and to have nominally high and low levels of drought resistance that were related to paddock management, geomorphology, and climate.