|Betancourt, J - USGS TUCSON|
Submitted to: Ecological Society of America Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: August 5, 2001
Publication Date: August 6, 2000
Citation: PETERS, D.C., BETANCOURT, J.L. CLIMATIC TRIGGERS FOR NONLINEAR AND THRESHOLD RESPONSES OF RANGELANDS. 86TH ANNUAL MEETING, ECOLOGICAL SOCIETY OF AMERICA. 2000. ABSTRACT P. 31. Technical Abstract: Climatic triggers to threshold responses have been observed for a number of ecosystem types, although our understanding and prediction of these responses remain limited. Our objective was to examine and synthesize the conditions under which climate is expected to trigger both larger and smaller than expected positive or negative ecosystem responses. These ecosystem "surprises" are related to interactions among properties of the climate (severity, duration, and frequency of extreme events), vegetation (e.g., species composition, age structure, and sex ratios) and soil (e.g., water-holding capacity, soil organic matter content). Management has important influences on the vegetation and soil that affect the ability of the ecosystem to respond to climatic events. Furthermore, thresholds observed at one spatial or temporal scale may or may not be observed at larger or smaller scales. We illustrate the importance of these interacting properties to ecosystem responses to climate across temporal and spatial scales using both paleoecological data and information from current vegetation for a number of ecosystem types. We then provide a general framework for understanding climatic triggers to threshold responses that can be used to guide research and assist in setting management priorities.