Minnesota’s native plant community classification: From a set of vegetation plot data to a statewide classification

Background/Question/Methods

Researchers with the Minnesota Department of Natural Resources undertook a nearly decade-long effort beginning in the mid-1990s to develop a new quantitative, statewide classification of native plant communities for Minnesota. The classification, which was designed specifically for use in biodiversity conservation and forest management, was developed using multiple numerical tools, including ordination, cluster analysis, and indicator species analysis, to guide classification of plant species data from 5,224 plots spanning most of the range of terrestrial and wetland vegetation in the state. Analyses of plant species data were supplemented with interpretation of soils data and other environmental data in defining and delineating classification entities. During its development, the plant community classification was integrated with Minnesota’s ecological land classification system, which provided a framework for regionalization of analytical datasets and helped to link physiographic information to floristic data.

Results/Conclusions

Minnesota’s classification is hierarchical, with six levels. Among the upper levels is the Ecological System, which groups plant communities according to influence by major ecological processes such as flooding or fire. Ecological Systems are well suited for landscape-scale biodiversity conservation and forest resource mapping and planning. Another important upper level, the Floristic Region, highlights geographic patterns of plant distribution that became apparent only after numerous rounds of analysis of plot data and development of lower levels of the classification. In some instances these patterns correlate strongly with paleo-vegetation patterns. The lowest levels of the classification correlate with local gradients of moisture and nutrients for terrestrial communities and with water chemistry and water-level fluctuations for wetland communities; these units are being widely applied to site-scale conservation and management activities. The Minnesota Department of Natural Resources has developed a series of products for application of the classification, including field guides for identification and interpretation of plant communities and silvicultural interpretations centered around native plant communities. The classification has served as a tool for new avenues of communication among plant ecologists, foresters, and other resource scientists and has elicited new ways of thinking about vegetation in Minnesota and the factors that influence it.