Submitted to: Ecological Society of America Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: August 5, 2001
Publication Date: August 5, 2001
Citation: BESTELMEYER, B.T., STRINGHAM, T., BROWN, J.R., HAVSTAD, K.M. DEVELOPING AND APPLYING STATE-AND-TRANSITION MODELS TO MANAGE RANGELANDS. 86TH ANNUAL MEETING, ECOLOGICAL SOCIETY OF AMERICA. 2001. ABSTRACT P. 7. Technical Abstract: State-and-transition models represent theories about the causes of threshold changes between ecosystem types in response to temporal changes in land use and/or climate. In contrast to the quantitative climax model that views ecosystem change as gradual and reversible, the state-and-transition concept holds that disturbances catalyze a shift in positive feedbacks between plants and ecosystem properties, such as nutrient availability and erosion potential, that may lead to irreversible changes in plant and animal composition. Applying this concept to rangeland management will require attention to the processes underlying threshold changes in varying contexts. We propose a set of standard definitions and a format for displaying individual state-and-transition models. We discuss how various sources of information on the processes underlying plant community pattern and dynamics can be brought together to develop predictive state-and-transition models. We argue the utility of models depends critically upon 1) the identification of appropriate spatial and temporal scales for measurement and management, 2) the identification of appropriate windows of climatic, topographic, and soil conditions within which systems behave similarly and that serve as a basis for model classification, 3) the recognition of system openness to landscape influences, and 4) acknowledgment of the case-contingent operation of different mechanisms. We illustrate how insights from community and landscape ecology can be blended with the historical perspective and practical experiences of land managers to build models.