Ecoregions of the conterminous United States: evolution of a hierarchical spatial framework.

摘要: A map of ecological regions the conterminous United States, first published in 1987, has been greatly refined and expanded into a hierarchical spatial framework response to user needs, particularly by state resource management agencies. In collaboration with scientists managers from numerous agencies institutions Mexico, Canada, cover North America, original ecoregions (now termed Level III) have refined, subdivided, aggregated identify coarser as well more detailed units. The most generalized units (Level I) define 10 U.S., while finest-scale IV) 967 ecoregions. this paper, we explain logic underpinning approach, discuss evolution regional mapping process, provide examples how were distinguished at each level. variety applications ecoregion illustrates its utility assessment management.