Topographic modeling of habitat suitability in the alpine tundra ecosystem: An integrated geographic information systems approach.

摘要

The basic intent of this research was to examine the spatial pattern and composition of alpine tundra using an integrated geographic information system (IGIS) approach. This study examined the alpine tundra ecosystem in terms of the biophysical factors that affect its spatial pattern and composition, to determine if there are areas within the ecosystem and the forest-alpine tundra ecotone (FATE) that are suitable for conifer growth, and hence, the migration of treeline components. Biophysical factors used in the analysis included topoclimatic, biogeographic, and edaphic controlling factors.; Biophysical data were collected for four alpine tundra sites in Glacier National Park, Montana (Logan Pass, Siyeh Pass, East Flattop Mountain, and Scenic Point) using remote sensors, in-situ techniques, and ancillary sources, and integrated in a raster-based GIS framework. The IGIS database was analyzed using digital image processing techniques and GIS cartographic modeling techniques, to create landscape feature sets. Feature sets contained individual biogeographic, topoclimatic, and edaphic data layers at two geographic scales, regional/local-scale (spatial resolution 30 x 30m) and micro-scale (spatial resolution 10 x 10m and 5 x 5m). These data layers represented key biophysical variables observed to control the pattern and composition of alpine tundra and the FATE.; The landscape feature sets were recombined, using a function-oriented additive approach, to create suitability models containing an index of habitat suitability potential for conifer growth, for each regional/local-scale and micro-scale site. Areas identified as suitable habitat were surveyed in the field to verify the reliability of the modeling approach. Other biophysical factors affecting the alpine ecosystem and the FATE, not included in the habitat suitability model, and recommendations for future research are discussed.; Significant contributions of this research include: (1) development of a multi-scale IGIS database which can be used as a baseline for future studies of alpine tundra and environmental change; (2) development of a model for identifying the habitat suitability of sites within the alpine tundra ecosystem for future study and monitoring; and (3) a methodology for integrating remote sensor, in-situ, GPS survey, and GIS techniques for modeling biophysical processes affecting the alpine tundra, the FATE, their spatial pattern and distributions, and their potential for change.