States, Transitions, and Thresholds: Further Refinement for Rangeland Applications

摘要

Applied ecology disciplines, such as range management, are necessarily organized around a response model based on theoretical supposition. Thus, the litmus for an ecological process model is its ability to predict the consequences of natural disturbances and/or management activities with acceptable precision over timescales relevant to management. Traditional theories of plant succession leading to a single climax community have been found to be inadequate for understanding the complex successional pathways of semi-arid and arid rangeland ecosystems considering timescales important for making management adjustments. The USDA National Resources Conservation Service (NRCS) adopted the use of state-and-transition vegetation dynamics in describing rangeland ecological sites. The attempt to use this concept illustrated the inconsistency in the definitions and concepts. NRCS recognizes the need for consistency in the application of the concepts. In order for management to utilize the non-equilibrium model the definitions of model objects must be succinctly stated and validated.