The Utility of Models in the Study of Mountain Development and Transformation

Abstract

A conceptual model presents the major components of a system and their interactions. If biotic components are repre- sented, it is an ecosystem model. If geomorphic and landscape processes are included, it is a geosystem model. Processes may be organized hierarchically, according to different rates and scales. This paper describes a conceptual model of the alpine geosystem of the southern Rocky Mountains, with snow and wind as the principal driving variables affecting system structure and function. A simulation model derived from the conceptual model indicates the responses of treeline elevation and tundra vegetation communities to changing climatic trends. Natural disturbances are represented as functions or process rates acting outside their traditional hierarchy levels, thereby modifying the normal order of geosystem processes. Forest models and tree-growth models are reviewed and compared, and the urgent need to integrate these and hydrologic models with the economies and activities of mountain people is emphasized. The Obergurgl Model is an example of such integration for a specific location and set of conditions. Effort must now be devoted to linking appropriate models of mountain geosystems with economic, sociological, and religious goals to provide a general theory of people-mountain interactions in the world.