A framework for estimating the consequences of alternative carrying capacity levels in Yosemite Valley

Abstract In the total process of developing a master plan for Yosemite National Park, the determination of appropriate visitor uses and use levels within Yosemite Valley is of great significance. The valley is a relatively self-contained component of the park, it has unique, nationally significant resources, and is the primary destination for a large number of park visitors. Changes in use types or levels in the valley could significantly affect the basic values of the area by either improving or impairing their preservation. The ability to assess the relative consequences of such changes is a critical decisionmaking tool in management planning. A scheme for making these assessments is presented in this paper. Evaluation of park history, legislation, and management policies identified scenery and natural biotic communities as the primary resource values in Yosemite Valley. The lands within the valley were classified and mapped according to three “quality” levels of each resource value producing a summary of area within each of nine scenic/ biotic resource catagories. Existing use patterns were evaluated relative to criteria for “acceptable uses” within each scenic/biotic type. Areas violating these criteria were subtracted from the “existing conditions” data to produce a corrected set of “baseline” data. All proposed alternatives for use allocation can be assessed against these baseline data to determine if conditions for the preservation of scenic and biotic resource of the Valley would be improved or impaired by the new use pattern. Possible uses of the assessment approach in other parks are discussed.