A PROCESS FOR SELECTING INDICATORS FOR MONITORING CONDITIONS OF RANGELAND HEALTH

This paper reports on a process for selecting a suite of indicators th at, in combination, can be useful in assessing the ecological conditio ns of rangelands. Conceptual models that depict the structural and fun ctional properties of ecological processes were used to show the linka ges between ecological components and their importance in assessing th e status and trends of ecological resources on a regional scale. Selec tion criteria were developed so that relationships could be assessed a t different spatial scales using ground and aerial measurements. Param eters including responsiveness and sensitivity to change, quality assu rance and control, temporal and spatial variability, cost-effectivenes s and statistical design played an important role in determining how i ndicators were selected. A total of ten indicator categories were sele cted by a committee of scientists for evaluation in the program. A sub set that included soil properties, vegetation composition and abundanc e, and spectral properties was selected for evaluation in a pilot test conducted in 1992 in the Colorado Plateau region of the southwestern United States. This work is part of a major effort being undertaken by the U.S. Environmental Protection Agency and its collaborators to ass ess the condition of rangelands (primarily comprised of arid, semi-ari d and dry subhumid ecosystems) along with seven other ecosystem groups (forests, agricultural lands, wetlands, surface waters, landscapes, e stuaries and Great Lakes) as part of a national Environmental Monitori ng and Assessment Program (EMAP). The indicator selection process repo rted upon was developed to support EMAP's goal of providing long-term, policy-relevant research focusing on evaluating the ecological condit ion (or health) of regional and national resources.