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LEVEL I, II, AND III ECOREGIONS OF NORTH AMERICA
Description:
Many of the environmental issues which we face today are ecosystem in scope and do not correspond to jurisdictional or administrative boundaries. Adopting an ecosystem approach to environmental resource management and risk assessment requires an understanding of the spatial nature of ecosystems regarding their interrelationships,capacities, and resiliency to human stresses. Such an approach has been sought byprofessionals, associations, government agencies, business, industry, and academia to serve as a common ground for integrating existing information about ecosystems. A descriptive ecoregional framework is an essential element for the ecological approach to be applied effectively across state, provincial, and country jurisdiction boundaries. An example of an immediate application of the framework involves North America Free Trade Agreement (NAFTA) decisions that may have an effect on ecosystem quality. The map of North American Ecological Areas is a product which has been jointly prepared by State of the Environment (Department of the Environment, Canada) andthe United States Environmental Protection Agency, Environmental Research Labratory, Corvallis, OR. The map classifies the terrestrial portions of North America in broad-scale regionalized units based on their ecological characteristics. To serve a wide variety of clients, the ecosystems were defined using a combination of factors including physiography, geology, soils, hydrology, climate, land use, vegetation, and wildlife. Because of possible confusion with other meanings of terms for different levels of ecologic regions, a Roman numeral classification scheme has been adopted for this effort. Level I is the coarsest level, dividing North America into 15 ecological regions whereas at Level II the continent is subdivided into 52 classes. Level III is subdivied into 194 classes.