Ecology and Plant Communities of the Colorado Plateau
The Colorado Plateau has been defined in various ways by different agencies and organizations. The EPA defines the Colorado Plateau Level III Ecoregion as primarily the southeastern portion of Utah and southwestern portions of Colorado, with minor inclusions of northern Arizona and northwestern New Mexico. The U.S. Forest Service, on the other hand, defines the Colorado Plateau Semidesert Province (3.9 mb) as primarily in northern Arizona and northwestern New Mexico with relatively minor inclusions of Utah and southwestern portions of Colorado.
For this reason, and because it has been defined in such broad terms, the Colorado Plateau Native Plant Program (CPNPP) has chosen to combine these definitions for the most part, by including the Colorado Plateaus, Arizona/New Mexico Plateau, and Arizona/New Mexico Mountain EPA Level III Ecoregions (see figure below). Colorado Plateau includes the Uinta Basin in the north and runs about 550 miles south to the Mogollon Rim in Arizona. Elevations of this area range from near 2,000 feet at the surface of the Colorado River as it runs through the Grand Canyon to over 12,000 feet in the Henry and LaSal Mountains of southeastern Utah. And vegetation patterns in the Colorado Plateau are indicative of this. It includes the red rock desert ecosystems as well as high elevation plateaus with expanses of pinyon-juniper woodlands and shrublands, sagebrush shrublands, blackbrush-Mormon tea shrublands, salt desert shrublands, communities and isolated mountain peaks.