|
(Gutierrezia sarothrae), Spiny greasebush (Forsellesia meionandra), Torrey's ephedra (Ephedra
<br /> torreyana), needle-and-thread grass (Hesperostipa comata), Indian ricegrass (Achnatherum
<br /> hymenoides), squirrel tail (Elymus elymoides), rose heath (Chaetopappa ericoides), mountain
<br /> pepperweed (Lepidium montanum), spiny phlox (Phlox hoodii), and spearieaf buckwheat (Eriogonum
<br /> lonchophyllum),and tawny cryptantha(Oreocarya nitida). Occasional trees of pinyon pine(Pinus edulis)
<br /> were observed in a few areas but are not common.
<br /> Greasewood Flats
<br /> Greasewood (Sarcobatus vermiculatus) communities are found along the larger draws, washes, and
<br /> stream terraces. The greasewood flats tend to be more heavily impacted by grazing and support low
<br /> vegetative diversity.Sitestypically have saline soils,a shallow water table, mayflood intermittently, but
<br /> remain dry for most of the growing season. However,the watertable remains high enough to maintain
<br /> vegetation,despite salt accumulations.This system occurs as an open to moderately dense shrublands
<br /> dominated by greasewood. Other shrubs that may be present include four-winged saltbush (Atriplex
<br /> canescens), shadscale (Atriplex con ferti folia), and winter-fat (Krascheninnikovia lanata). Adjacent to
<br /> ephemeral stream channels, basin big sagebrush (Artemisia tridentata var. tridentata) and rubber
<br /> rabbitbrush(Ericameria nauseosus)occasionally occur.Stock ponds,where present,additionally include
<br /> dense stands of cocklebur (Xanthium strumarium), annual sunflower (Helionthus annuus), and
<br /> goosefoot species(Chenopodium sp.).
<br /> These open shrublands and steppe occur in canyons,gravelly draws,hilltops,and dry flats.characterized
<br /> by Bigelow sage (Artemisia bigelovii) or black sage (A. nova). Typical grass species include Indian
<br /> ricegrass,purple threeawn(Aristida purpurea), blue grama(Bouteloua gracilis), needle-and-thread, and
<br /> James'galleta(Hilaria jamesii).
<br /> Mat Saltbush Shrubland
<br /> The mat saltbush(Atriplex gardneri, A. corrugata)shrublands occur on lower elevations of the project
<br /> area on Mancos Shale derived clay soils. Such soils tend to swell when wet,then shrink as they dry out,
<br /> causing significant movement in the upper part of the soil column making it difficult for many plants to
<br /> grow.Mat saltbush shrublands are considered dwarf-shrublands as they are composed of relatively pure
<br /> stands of the low growing mat saltbush or Gardner's saltbush(Atriplex gardneri),typically with a sparse
<br /> herbaceous layer. Other dwarf-shrub species that may be present include spineless horsebrush
<br /> (Tetradymia canescens), rabbitbrush (Chrysothamnus spp.), and occasionally shadscale. Common
<br /> graminoids and forbs include James' galleta grass, Indian ricegrass, desert prince's plume (Stanleya
<br /> pinnata), prickly phlox, cleftleaf wildheliotrope(Phacelia crenulata), and sego lily(Calochortus nuttallii).
<br /> Semi-Desert Grassland
<br /> Dry grasslands occupy much of the project area and form a mosaic with the other vegetation
<br /> communities. These grasslands are typically dominated by drought-resistant perennial grasses
<br /> previously mentioned such as Indian ricegrass, blue grama, needle-and-thread, James' galleta, and
<br /> purple threeawn. Scattered shrubs are often present including snakeweed, fourwing saltbush, and
<br /> winterfat(Krascheninnikovia lanata).Common forbs include copper mallow(Sphaeralcea coccinea)along
<br /> with prickly pear(Opuntia polyacantha),woolly plantain(Plantago patagonica), cleftleaf wildheliotrope,
<br /> and tawny cryptantha(Oreocarya nitida).
<br />
|