A QUANTITATIVE APPROACH TO DEVELOPING REGIONAL ECOSYSTEM CLASSIFICATIONS

Ecological land classification systems have recently been developed at continental, regional, state, and landscape scales. In most cases, th e map units of these systems result from subjectively drawn boundaries , often derived by consensus and with unclear choice and weighting of input data. Such classifications are of variable accuracy and are not reliably repeatable. We combined geographic information systems (GIS) with multivariate statistical analyses to integrate climatic, physiogr aphic, and edaphic databases and produce a classification of regional landscape ecosystems on a 29 340-km(2) quadrangle of northwestern Wisc onsin. Climatic regions were identified from a high-resolution climati c database consisting of 30-yr mean monthly temperature and precipitat ion values interpolated over a 1-km(2) grid across the study area. Pri ncipal component analysis (PCA) coupled with an isodata clustering alg orithm was used to identify regions of similar seasonal climatic trend s. Maps of Pleistocene geology and major soil morphosequences were use d to identify the major physiographic and soil regions within the land scape. Climatic and physiographic coverages were integrated to identif y regional landscape ecosystems, which potentially differ in character istic forest composition, successional dynamics, potential productivit y, and other ecosystem-level processes. Validation analysis indicated strong correspondence between forest cover classes from an independent ly derived Landsat Thematic Mapper classification and ecological regio n. The development of more standardized data sets and analytical metho ds for ecoregional classification provides a basis for sound interpret ations of forest management at multiple spatial scales.