Plant adaptation regions: Ecological and climatic classification of plant materials

The effective use of plant materials for an array of objectives including conservation, restoration, renovation, landscaping, and bioremediation requires knowledge of the adaptation of each species and, more specifically, knowledge of the adaptation of cultivars, strains, accessions, or ecotypes of a species to specific sites or regions. For agronomic and horticultural plants, specific adaptation information has been and continues to be developed by extensive testing. Rangeland, grassland, park, and restoration project managers often lack the resources to determine adaptation areas for plant materials because of the large number of species that are used and the extensive geographical areas that are serviced. Problems often arise in delineating adaptation areas for plant materials of both native and introduced species. Since ecoregion and plant hardiness zone classification systems integrate many climatic and geographic variables that determine plant adaptation, these 2 systems can be combined to develop Plant Adaptation Regions (PARs). A PAR map of the contiguous United States was developed by merging a widely used ecoregion map with the USDA Plant Hardiness Zone map, and is available in GIS format. Based on their geographic origins and/or test results, plant materials and their general areas of adaptation can be classified using PARs.