A REGIONAL FRAMEWORK FOR ANALYZING WEED SPECIES AND ASSEMBLAGE DISTRIBUTIONS USING A GEOGRAPHIC INFORMATION-SYSTEM

This paper presents a framework in which the spatial and temporal doma in of weed populations can be analyzed using geographically referenced information. The regional framework for analysis is based on the prem ise that the domain of a weed species or an assemblage of species can be described in terms of the space and time in which they survive. Pub lished maps of the spatial distribution of individual weed species wer e converted to digital records defining their geographic domain. Digit al records were imported into a geographically referenced data system. Assemblage maps were produced by intersecting domains of individual s pecies. The assemblage maps show areas with similar intensity of the o ccurrence of species selected for analysis. The most intense occurrenc e of summer annual species, for example, exists in a relatively small area of the Midwest. The framework presented in this paper is a concep t for a tool to evaluate, manage, and manipulate weed distribution dat a at the regional scale. Analysis at the regional scale is a perspecti ve substantially different from the plot or field-scale analysis tradi tionally used to study and manage weed populations. Regional analysis has application to weed science by increasing the understanding of reg ional patterns of weed infestation and the factors that regulate them. This information will be useful to the herbicide industry, plant ecol ogists, resource managers, and agricultural policy makers.