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Pinyon-Juniper This community includes the very western portions of the site to be <br />Woodlands mined, as well as the buffer zones on the west and north. Characteristic <br /> vegetation includes Twoneedle pinyon (15%), Utah juniper (15%), Big <br /> sagebrush (20%), Ponderosa pine (<10%) Muttongrass (10%), Western <br /> wheatgrass (10%), and Indian ricegrass (5%). Production varies from 500 <br /> to 700 pounds per acre. Some of these areas will be mined, but the <br /> buffer areas will be not mined and will remain as reservoirs and habitat <br /> for wildlife, while the mined area is reclaimed as pine-grassland <br /> (possibly irrigated) for grazing. Pinyon-Juniper Woodland type occurs <br /> on warm, dry sites on mountain slopes, mesa, plateaus, and ridges at <br /> elevations from 5000 to 8000 feet. Soils vary in texture from stony, <br /> cobbly, gravelly sandy loams to clay loam or clay. Pinyon and/or Utah <br /> juniper dominate the tree canopy. Rocky Mountain juniper may <br /> codominate or replace Utah juniper at higher elevations. Understory <br /> layers are variable and may be absent or may be dominated by <br /> shrubs, or grasses. Associated species include greenleaf manzanita, big <br /> sagebrush, mountain mahogany, blackbrush, cliffrose, antelope <br /> bitterbrush, Gambel oak, blue grama, galleta, or muttongrass. <br /> Specimen Ponderosa may be found throughout the community, but <br /> the highest part of the site (the west-facing slopes in the eastern buffer <br /> zone) has significant numbers of Ponderosa pine in thick stands mixed <br /> with the Pinyon-Juniper; these areas may have once been (prior to <br /> grazing and fire suppression) purely Ponderosa, until invasion of pinyon <br /> and juniper took place. (USBR 1999) <br />Pine-Grassland More properly an ecotone, which was not mapped by NRCS at this <br /> location, but nonetheless has some bearing on understanding of the <br /> ecosystems. This interface between the semi-arid loamy foothills <br /> grasslands and shrublands and the Pinyon-Juniper woodlands is <br /> characterized by an open, savannah setting, especially on flatter <br /> slopes, where grass predominates over trees and shrubs which are, <br /> nonetheless, still present in significant numbers. It is typical for this <br /> community to have been greatly reduced in area through a decline in <br /> herbaceous vegetation (grasses and non-woody flowering plants) <br /> while forests thicken and brush invades. This is caused by a <br /> combination of fire suppression and grazing, particularly overgrazing by <br /> cattle and horses; however, this site shows fewer signs of that <br /> progression than most similar sites in Montezuma County, due to site <br /> improvement for irrigation, mining, and water availability. This <br /> community is also a mix of two different grasslands types: Plains <br /> grasslands are commonly dominated by Blue Grama or other gramas <br /> that extend across southern Colorado into northwestern New Mexico, <br /> while Great Basin grasslands are dominated by Galleta Grass and <br /> Indian Rice Grass and reach down to the Colorado Plateau from the <br /> northwest. Other species are common with the Pinyon-Juniper <br /> community. Most of the area to be mined (the bench above the <br /> rimrock cliffs) is this community: grassland with scattered trees and <br /> shrubs. Production varies from 600 to 800 pounds per acre. This <br /> community will be effectively restored and expanded by reclamation <br /> after mining, as areas that are now Pinyon-Juniper are reclaimed as <br /> grassland, but some invasion of woody species continues. <br />Exhibits for 1 12(c) AM-02 Application - M-1994-108 - 2010 - Page 53