APPENDIX C
DESCRIPTIONS OF LAND COVER TYPES FOUND WITHIN OR NEAR YUCCA MOUNTAIN AND THE POTENTIAL TRANSPORTATION CORRIDORS AND FACILITIES
(University of California 1994; Utah State University 1996)
Nevada
Land cover type descriptions are from the Nevada Gap Analysis (Utah State University 1996) and are based on dominant species. This is not intended to be a complete species list, but rather an overview of the most common species associated with each cover type. The minimum mapping unit was 30 m, with the primary data source being Thematic Mapping images. Five of the land cover types found near Yucca Mountain were identified using screen interpretation, with the remainder using digital classification techniques (Utah State University 1996).
AGRICULTURE (AG) - Row crops, irrigated pasture and hay fields, dry farm crops. Distribution - Located state-wide. ASH (ASH) - Woodland dominated by velvet ash Fraxinus velutina and screwbean Prosopis pubescens. Primary associated shrub species includes Baccharis emoryi. Distribution - This cover type is only found in the vicinity of Ash Meadows, near Amargosa Valley. BARREN (BAR) - Barren soil or rock with less than five percent total vegetative cover. Distribution - This class is distributed throughout Nevada with the majority being low elevation barren soil or high elevation rock cliffs and talus slopes. BLACKBRUSH (BB) - Shrubland principally dominated by blackbrush Coleogyne ramosissima. Primary associated tree species include juniper Juniperus osteosperma. Primary associated shrub species include spiny hopsage Grayia spinosa, mormon tea Ephedra spp., shadscale Atriplex confertifolia, desert thorn Lycium spp., snakeweed Xanthocephalum spp., and creosote Larrea tridentata. Other associated species include joshua tree Yucca brevifolia, and yucca Yucca spp. Distribution - Blackbrush is typically a transition vegetation class between Mojave scrub and Great Basin shrubs. It typically occurs in elevation transition areas between 4,000-5,000 feet (1,200-1,500 m) and in latitude transition areas north of creosote-bursage. CREOSOTE-BURSAGE (CB) - Scrubland principally dominated by creosote Larrea tridentata and white bursage Ambrosia dumosa. Primary associated shrub species include blackbrush Coleogyne ramosissima, mormon tea Ephedra spp., dalea Dalea fremontii, shadscale Atriplex confertifolia, hopsage Grayia spinosa, desert thorn Lycium spp., ratany Krameriaceae parvifolia, burro bush Hymenoclea salsola, honey mesquite Prosopis glandulosa, and brittlebush Encelia farinosa. Other associated species include joshua tree Yucca brevifolia, yucca Yucca spp., prickly pear Opuntia engelmannii and cholla. Distribution - This class occurs widely within the Mojave desert below 4,000 feet (1,200 m) and typically is found in valley bottoms, lowlands and flatlands of mild slope. GRASSLAND (GL) - Perennial and annual grasslands. Principle perennial grass species include wheatgrasses Agropyron spp., bluegrass Poa spp., basin wildrye Elymus cinereus, galleta Hilaria spp., needlegrass Stipa spp., sand dropseed Sporobolus cryptandrus, blue gramma Bouteloua gracilis, squirreltail Sitanion hystrix and Indian ricegrass Oryzopsis hymenoides. Principle annual grass species include cheatgrass Bromus tectorum. Primary associated shrub species include sagebrush Artemisia spp., shadscale Atriplex confertifolia, greasewood Sarcobatus vermiculatus and creosote Larrea tridentata. Primary associated tree species include juniper Juniperus spp. Distribution - This is a wide-spread, broadly defined class distributed mostly in central and northern Nevada. The majority of this class occurs as a result of seeded perennial grasslands or fire induced annual grasslands; however, it also includes valley, foothill, and mountain native grasslands. GREASEWOOD (GW) - Shrubland principally dominated by greasewood Sarcobatus vermiculatus. Primary associated shrub species include shadscale Atriplex confertifolia, iodine bush Allenrolfea occidentalis, basin sagebrush Artemisia tridentata var. tridentata and bailey greasewood Sarcobatus baileyi. Other associated species include seepweed Suaeda torreyana, halogeten Halogeten glomeratus and tumbleweed Salsola iberica. Distribution - Greasewood is found throughout Nevada, typically in the salt desert scrub zone. It is very salt tolerant and can usually be found on flat valley floors. HOPSAGE (HOP) - Shrubland characterized by the occurrence of hopsage Grayia spinosa, typically in concert with desert thorn Lycium spp, rabbitbrush Chrysothamnus spp., tea Ephedra spp. and shadscale Atriplex confertifolia. Primary associated shrub species include sagebrush Artemisia spp. blackbrush Coleogyne ramosissima, rabbitbrush Chrysothamnus spp., winterfat Ceratoides lanata, ratany Krameriaceae parvifolia, bursage Ambrosia dumosa, and creosote Larrea tridentata. Distribution - This is a transition shrubland, typically between Mojave and Great Basin ecosystems. This class occurs in the northern reaches of the Mojave and the southern fringe of the Great Basin. JUNIPER_1 (JUN1) - Conifer woodland principally dominated by Utah juniper Juniperus osteosperma at canopies less than 30 percent. Primary associated tree species include Rocky Mountain juniper Juniperus scopulorum, western juniper Juniperus occidentalis and single leaf pinyon Pinus monophylla. Primary associated shrub species include sagebrush Artemisia spp., rabbitbrush Chrysothamnus spp., and blackbrush Coleogyne ramosissima. Distribution - Juniper is widely distributed throughout Nevada in open canopy stands. It typically occurs at lower elevations below the pinyon-juniper zone. In southern Nevada, juniper occurs commonly with blackbrush. JUNIPER_2 (JUN2) - Conifer woodland principally dominated by juniper Juniperus osteosperma at canopies from 30-60 percent. Primary associated tree species include Rocky Mountain juniper Juniperus scopulorum, western juniper Juniperus occidentalis, and single leaf pinyon Pinus monophylla. Primary associated shrub species include sagebrush Artemisia spp., rabbitbrush Chrysothamnus spp., and blackbrush Coleogyne ramosissima. Distribution - Juniper is widely distributed throughout Nevada in open canopy stands. It typically occurs at lower elevations below the pinyon-juniper zone. Northern Nevada contains only juniper, with small stands of western juniper in extreme northwest Nevada. In southern Nevada, juniper occurs commonly with blackbrush. LOWLAND RIPARIAN (LRP) - Localized vegetation influenced by the presence of abundant water in contrast to the surrounding landscape in lowland areas. Principal tree species include Fremont cottonwood Populus fremontii and black cottonwood Populus trichocarpa. Principal shrub species include salt cedar Tamarix pentandra, velvet ash Fraxinus velutina, desert willow Chilopsis linearis, and mesquite Prosopis glandulosa. Distribution - Riparian areas generally lower than 4,000 feet (1,200 m) in the Mojave and 5,000 feet (1,500 m) in the remaining areas of Nevada. Velvet ash, desert willow, and mesquite are only found in the Mojave. This class is common along the Carson, Colorado, Humboldt, Truckee, Virgin, and Walker rivers. MESQUITE (MES) - Shrubland dominated by mesquite Prosopis glandulosa. Primary associated shrub species include salt cedar Tamarix pentandra, torrey saltbush Atriplex torreyi, and creosote Larrea tridentata. Distribution - This cover type is only found principally on the west side of the Mojave desert in scattered clumps. MOJAVE BRISTLECONE_2 (MBC2) - Conifer forest principally dominated by bristlecone pine Pinus aristata at canopies from 30-60 percent. Primary associated tree species include limber pine Pinus flexilis, Engelmann spruce Picea engelmannii, white fir Abies concolor, and ponderosa pine Pinus ponderosa. Primary associated shrub species include sagebrush Artemisia spp. and snowberry Symphoricarpos spp. Distribution - This class is distributed in the Snake and Sheep mountains within the Mojave Desert, usually from 9,000-11,500 feet (2,700-3,500 m). MOJAVE MIXED SCRUB (MMS) - Mojave desert mixed scrublands are usually characterized by the occurrence of creosote Larrea tridentata in association with several possible species, including bursage Ambrosia dumosa, dalea Psorothamnus fremontii, desert thorn Lycium spp., shadscale Atriplex confertifolia, hopsage Grayia spinosa, ratany Krameriaceae parvifolia, and tea Ephedra spp. Primary associated shrub species include blackbrush Coleogyne ramosissima, brittlebrush Encelia farinosa, burro bush Hymenoclea salsola, bebbia Bebbia juncea, desert saltbush Atriplex polycarpa, and desert holly Atriplex hymenelytra. Other associated species include joshua tree Yucca brevifolia., yucca Yucca spp., cacti Echinocereus spp., and cholla Opuntia biglovii. Distribution - This class typically occurs on slopes, washes, or upland areas within the Mojave desert that are difficult to characterize because of several mixed shrub species with no clear dominance. MOUNTAIN SAGEBRUSH (MSB) - Mountain shrubland dominated or co-dominated by mountain big sagebrush Artemisia tridentata ssp. vaseyana, subalpine sagebrush Artemisia tridentata ssp. spiciformis, low sagebrush Artemisia arbuscula, and silver sagebrush Artemisia cana, in concert with mountain shrubs, grasses and forbs. Primary associated tree species include pinyon Pinus monophylla, mountain mahogany Cercocarpus ledifolius, limber pine Pinus flexilis, white fir Abies concolor, subalpine fir Abies lasiocarpa, Engelmann spruce Picea engelmannii, ponderosa pine Pinus ponderosa, lodgepole pine Pinus contortus, whitebark pine Pinus albicaulis, and Jeffrey pine Pinus jeffreyi. Primary associated shrub species include snowberry Symphoricarpos spp., alder leaf mountain mahogany Cercocarpus montanus, bitterbrush Purshia tridentata, littleleaf mountain mahogany Cercocarpus intricatus, buckbrush Ceanothus spp., manzanita Arctostaphylos spp., ninebark Physocarpus alternans, currant Ribes spp., squawbush Rhus spp., and cliffrose Cowania mexicana. Distribution - This class is widespread throughout Nevada mountains, usually at elevations from 6,500-10,000 feet (2,000-3,000 m). It is especially prevalent in central and northern Nevada where mountain forests are minimal. MOUNTAIN SHRUB (MNS) - Deciduous shrubland principally dominated by oak Quercus spp., maple Acer spp., alder leaf mountain mahogany Cercocarpus montanus, cliffrose Cowania mexicana, bitterbrush Purshia tridentata, serviceberry Amelanchier spp., buckbrush Ceanothus spp., snowberry Symphoricarpos spp., manzanita Arctostaphylos spp.,ninebark Physocarpus alternans, currant Ribes spp., squawbush Rhus spp., and littleleaf mountain mahogany Cercocarpus intricatus. Primary associated shrub species include sagebrush Artemisia spp. and rabbitbrush Chrysothamnus spp. Primary associated tree species include pinyon Pinus monophylla, juniper Juniperus osteosperma, mountain mahogany Cercocarpus ledifolius, aspen Populus tremuloides, white fir Abies concolor, limber pine Pinus flexilis, ponderosa pine Pinus ponderosa, subalpine fir Abies lasiocarpa and Engelmann spruce Picea engelmannii. Distribution - This is a wide-spread class in the foothills and mountains of Nevada. Because of the landscape scale of the mapping, many of these species could not be isolated. The largest concentrations of this class are found in the mountains of southern, eastern, and northeastern Nevada. PINYON_1 (PN1) - Conifer woodland principally dominated by single leaf pinyon Pinus monophylla at canopies less than 30 percent. Primary associated tree species include Utah juniper Juniperus osteosperma, ponderosa pine Pinus ponderosa, white fir Abies concolor, mountain mahogany Cercocarpus ledifolius, and Jeffrey pine Pinus jeffreyi. Primary associated shrub species include sagebrush Artemisia spp., oak Quercus gambelii, alder leaf mountain mahogany Cercocarpus montanus, littleleaf mountain mahogany Cercocarpus intricatus, cliffrose Cowania mexicana, manzanita Arctostaphylos spp., shrub live oak Quercus turbinella, and bitterbrush Purshia tridentata. Distribution - Pinyon is most widely distributed throughout eastern, central, and western Nevada at elevations above the pinyon-juniper zone. It is absent in northern Nevada. PINYON_2 (PN2) - Conifer forest principally dominated by single leaf pinyon Pinus monophylla at canopies from 30-60 percent. Primary associated tree species include Utah juniper Juniperus osteosperma, ponderosa pine Pinus ponderosa, white fir Abies concolor, mountain mahogany Cercocarpus ledifolius, and Jeffrey pine Pinus jeffreyi. Primary associated shrub species include sagebrush Artemisia spp., oak Quercus gambelii, alder leaf mountain mahogany Cercocarpus montanus, littleleaf mountain mahogany Cercocarpus intricatus, cliffrose Cowania mexicana, manzanita Arctostaphylos spp., shrub live oak Quercus turbinella, and bitterbrush Purshia tridentata. Distribution - Pinyon is most widely distributed throughout eastern, central and western Nevada at elevations above the pinyon-juniper zone. It is absent in northern Nevada. PINYON-JUNIPER_1 (PJ1) - Conifer woodland principally co-dominated by single leaf pinyon Pinus monophylla and Utah juniper Juniperus osteosperma at canopies less than 30 percent. Primary associated tree species include mountain mahogany Cercocarpus ledifolius. Primary associated shrub species include sagebrush Artemisia spp., rabbitbrush Chrysothamnus spp., oak Quercus gambelii, alder leaf mountain mahogany Cercocarpus montanus, bitterbrush Purshia tridentata, littleleaf mountain mahogany Cercocarpus intricatus, and cliffrose Cowania mexicana. Distribution - Pinyon-Juniper is distributed throughout all but northern Nevada. It is most abundant in eastern and central Nevada. It typically occurs at elevations above the juniper zone and below the pinyon zone. PINYON-JUNIPER_2 (PJ2) - Conifer woodland principally co-dominated by pinyon Pinus monophylla and juniper Juniperus osteosperma at canopies from 30-60 percent. Primary associated tree species include mountain mahogany Cercocarpus ledifolius. Primary associated shrub species include sagebrush Artemisia spp., rabbitbrush Chrysothamnus spp., oak Quercus gambelii, alder leaf mountain mahogany Cercocarpus montanus, bitterbrush Purshia tridentata, littleleaf mountain mahogany Cercocarpus intricatus, and cliffrose Cowania mexicana. Distribution - Pinyon-Juniper is distributed throughout all but northern Nevada. It is most abundant in eastern and central Nevada. It typically occurs at elevations above the juniper zone and below the pinyon zone. PLAYAS (PLY) - Barren internal basin floors which can occasionally be covered by water. Distribution - Located state-wide on flat, low-elevation valley floors. PONDEROSA PINE_1/MOUNTAIN SHRUB (PP1/MNS) - Conifer woodland principally dominated by ponderosa pine Pinus ponderosa at canopies less than 30 percent, co-dominant with mountain shrubs including oak Quercus gambelii, alder leaf mountain mahogany Cercocarpus montanus, snowberry Symphoricarpos spp., manzanita Arctostaphylos spp., and littleleaf mountain mahogany Cercocarpus intricatus. Primary associated tree species include pinyon Pinus monophylla, juniper Juniperus osteosperma, white fir Abies concolor, limber pine Pinus flexilis, mountain mahogany Cercocarpus ledifolius, and bristlecone pine Pinus aristata. Primary associated shrub species include sagebrush Artemisia spp. Distribution - This class is predominantly found in the Spring, Sheep, and Clover mountains of southern Nevada. PONDEROSA PINE_2 (PP2) - Conifer forest principally dominated by ponderosa pine Pinus ponderosa at canopies from 30-60 percent. Primary associated tree species include pinyon Pinus monophylla, juniper Juniperus osteosperma, white fir Abies concolor, limber pine Pinus flexilis, mountain mahogany Cercocarpus ledifolius, and bristlecone pine Pinus aristata. Primary associated shrub species include sagebrush Artemisia spp., oak Quercus gambelii, alder leaf mountain mahogany Cercocarpus montanus, snowberry Symphoricarpos spp., manzanita Arctostaphylos spp., and littleleaf mountain mahogany Cercocarpus intricatus. Distribution - This class is predominantly found in the Spring, Sheep, and Clover mountains of southern Nevada, and the Snake, Wilson Creek, Quinn Canyon, and Schell Creek mountains of eastern Nevada. SAGEBRUSH (SB) - Shrubland principally dominated by big sagebrush Artemisia tridentata spp., black sagebrush Artemisia nova, or low sagebrush Artemisia arbuscula. Primary associated tree species include juniper Juniperus osteosperma, pinyon Pinus monophylla, mountain mahogany Cercocarpus ledifolius, Jeffrey pine Pinus jeffreyi, and ponderosa pine Pinus ponderosa. Primary associated shrub species include rabbitbrush Chrysothamnus spp., snakeweed Gutierrezia sarothrae, blackbrush Coleogyne ramosissima, shadscale Atriplex confertifolia, greasewood Sarcobatus spp., spiny hopsage Grayia spinosa, and bitterbrush Purshia tridentata. Primary associated grass species include wheatgrasses Agropyron spp., cheatgrass Bromus tectorum, bluegrasses Poa spp., needlegrasses Stipa spp., fescues Festuca spp., and galleta Hilaria jamesii. Distribution - Sagebrush is the most widespread and abundant cover type in Nevada. Typically this class occurs above 5,000 feet (1,500 m) with associated grass species making up less than 25 percent of the sagebrush canopy. SAGEBRUSH/PERENNIAL GRASS (SB/PG) - Co-dominant sagebrush Artemisia spp. shrubland and perennial grassland. Co-dominance is defined by either shrub or grass composing at least 25 percent of the total canopy. Principle grass species include wheatgrasses Agropyron spp., bluegrasses Poa spp., needlegrasses Stipa spp., fescues Festuca spp., ricegrass Oryzopsis hymenoides, and galleta Hilaria jamesii. Primary associated shrub species include rabbitbrush Chrysothamnus spp., bitterbrush Purshia tridentata, and cliffrose Cowania mexicana. Primary associated grass species include cheatgrass Bromus tectorum and squirreltail Elymus elymoides. Distribution - This class typically occurs mid-elevation between sagebrush and mountain sagebrush classes in central Nevada and is wide-spread as part of the sagebrush steppe of northern Nevada. SALT DESERT SCRUB (SDS) - Shrublands principally dominated by one or more of the following: shadscale Atriplex confertifolia, desert holly Atriplex hymenelytra, Bailey's greasewood Sarcobatus baileyi, desert thorn Lycium spp., Torrey saltbush Atriplex torreyi, winterfat Ceratoides lanata, budsage Artemisia spinescens, fourwing saltbush Atriplex canescens, Mormon tea Ephedra spp., Bailey's greasewood Sarcobatus baileyi, horsebrush Tetradymia canescens, and snakeweed Gutierrezia sarothrae. Primary associated shrub species include greasewood Sarcobatus vermiculatus, sagebrush Artemisia spp., blackbrush Coleogyne ramosissima, iodine bush Allenrolfea occidentalis, and creosote Larrea tridentata. Primary associated forb species includes halogeten Halogeten glomeratus. Primary associated grass species include saltgrass Distichlis spicata and cheatgrass Bromus tectorum. Distribution - This is a broad abundant class which can occur in a variety of physiographic areas throughout the state. Typically this class occurs below 5,000 feet (1,500 m), except for central Nevada, and especially dominates the Lahontan basin of western Nevada. SAND DUNES (SD) - Sand dunes with less than five percent total vegetative cover. Distribution - Located state-wide, with major dunes near Winnemucca and Sand Mountain near Fallon. WETLAND (WET) - Low elevation marsh and wetland areas. Principal species include cattail Typha latifolia, bullrush Scirpus spp., burreed Sparganium spp., common reed grass Phragmites australis, pondweed Potamogeton spp., and sedge Carex spp. Distribution - This class occurs in limited areas throughout Nevada, typically in low elevation basins around a permanent water source. The largest expanses occur in Ruby valley and the Carson Sink. WHITE FIR_2 (WF2) - Conifer forest principally dominated by white fir Abies concolor at canopies from 30-60 percent. Primary associated tree species include ponderosa pine Pinus ponderosa, pinyon Pinus monophylla, mountain mahogany Cercocarpus montanus, Engelmann spruce Picea engelmannii, limber pine Pinus flexilis and bristlecone pine Pinus aristata. Primary associated shrub species include sagebrush Artemisia spp., snowberry Symphoricarpos spp., buckbrush Ceanothus spp., and manzanita Arctostaphylos spp. Distribution - This class is distributed throughout eastern and southern Nevada typically above 7,500 feet (2,300 m) on north and east aspects. URBAN (URB)- Commercial, mining and residential areas. Distribution - Located state-wide.
California
Descriptions of land cover types within the 84-km circle from the California GAP Analysis, Mojave Ecoregion (University of California 1994). Data were produced by the University of California (1994), Santa Barbara, Department of Geography, and obtained from the World-Wide-Web. The minimum mapping unit was 100 ha, and the data used in the mapping was compiled from existing sources (e.g., BLM management plans, Southern California Edison resource inventories, Soil Conservation Service surveys, LANDSAT thematic images and field reconnaissance), as opposed to largely digital classification techniques used in Nevada.
ALKALI PLAYA: Poorly drained soils with high alkalinity due to evaporation of water accumulated in closed drainages. May have widely spaced alkaline tolerating shrubs such as Allenrolfea occidentalis, Atriplex confertifolia, A. parryi, and Sarcobatus vermiculatus. DESERT HOLLY SCRUB: Dominated by Atriplex hymenelytra; few other shrubs. DESERT SALTBRUSH SCRUB: Widely scattered cover type found on margins of dry lake beds on poorly drained, alkaline soils. Stands are typically dominated by a single Atriplex species, including Atriplex canescens, A. confertifolia, or A. polycarpa. Grayia spinosa and Lycium spp. commonly occur. DRY SALT FLAT: Non-playa alkaline encrusted barren area. DUNES AND SAND FIELDS: May be barren and active, stabilized and/or partially stabilized sand. Stabilized by the presence of evergreen, or deciduous shrubs, including Ambrosia dumosa, Astragalus spp., and Atriplex spp. MESQUITE BOSQUE: Occurs along washes, streambanks, or other areas with substantial near-surface groundwater supplies. Dense to open woodland dominated by Prosopis spp. Atriplex spp. is a commonly occurring shrub. MIXED BARREN LAND: Vegetation may exist, but cover is extremely low. MOJAVE CREOSOTE BUSH SCRUB: Widely spaced shrubs, usually with bare space in between. This is the basic creosote scrub of the Mojave Desert, dominated by Larrea tridentata or Larrea tridentata and Ambrosia dumosa. This cover type also may contain shrubs such as found in Mojave Mixed Woody Scrub as sub-dominants, including Ephedra nevadensis and Lycium spp. MOJAVE MIXED WOODY SCRUB: Varied in composition but generally characterized by one or several of the following species: Ambrosia dumosa, Tetradymia spp., Lycium spp., Coleogyne ramosissima (as a sub-dominant), Krascheninnikovia lanata, Psorothamnus arborescens, Thamnosma montanum, Hymenoclea salsola, Encelia spp., Yucca schidigera, and/or Eriogonum fasciculatum. MOJAVEAN PINON AND JUNIPER WOODLANDS: An open woodland, generally found between 1200-2500 m, dominated by Pinus monophylla and/or Juniperus spp. Shrubby understory species may include Coleogyne ramosissima, Eriogonum fasciculatum, and/or Ephedra nevadensis. QUARRY: Active or historic mining excavations. SHADSCALE SCRUB: Cover type often found on poorly-drained flats with heavy, slightly alkaline soils and on well drained slopes at slightly higher elevations (approximately 900-1800 m). Dominated by Atriplex confertifolia and/or Artemisia spinescens. URBAN: Includes residential, commercial, and industrial development.