Shrub-dominated Vegetation 



fc)"- 



Artemisia nova/Agropyron spicatuin plant association 



(ARTNOV/AGRSPI; black sagebrush/bluebunch wheatgrass; MTNHP raiik G5/S4; 

 WHTF designation Artemisia nova/Pseudoroegneha spicata; 2 plots) 



Environment: Fairly extensive examples of this type are found on dry, gently sloping, coarse- 

 textured, calcareous alluvial fans at the foot of the Ruby Range in the northeast corner of the 

 study area. It was sampled by two plots near the mouths of Portier and Laurin Canyons. 

 Elevations are about 6,000 feet or less, and aspect is easterly. Elsewhere in southwestern Montana 

 ARTNOV/AGRSPI usually occupies sites with west and south aspects (Cooper et al. 1995). 

 Uphill slopes are Artemisia tridentata var. raseyana/Agropyron spicatum steppe, and 

 Pseudotsnga menziesii forest types on northerly aspects. Downhill slopes are private valley lands 

 heavily grazed or converted to forage crop production. 



Soils: In the Ruby Range it occurs on dry, rocky soils with alluvium parent material derived 

 mostly from limestone. It was found on Crago very stony loam, a Calciorthid, and Hanson 

 chamiery loam, a Calcic Cryoboroll (USDA Soil Conservation Service 1989). Elsewhere in 

 Montana it is also found on calcareous substrates. 



Vegetation: Artemisia nova, a low sagebrush, is the dominant slirub (ca. 20% cover) along with 

 lesser amounts of Guttierezia sarothrae and Chysothamims nauseosus. The low tree (tall sluub) 

 Jimiperns scopulorum is scattered within the community type. Agropyron spicatum (syn. Elymus 

 spicatus, Pseudoregneria spicatum) is the dominant grass or codominant with Festuca idahoensis 

 with each having around 20% cover. No forbs are well represented, but species of Castilleja, 

 Phlox hoodii, and the exotic Tragopogon dubious are constant in both plots. 



Comments: The habitat has been grazed in the past but remains in relatively good condition. 

 Some spots with heavy shrub cover and bunchgrasses confined to growing from under shrubs 

 indicate past heavy grazing. A few plants of Centaurea maculosa (spotted knapweed) were found 

 a'^d the habitat may be susceptible to invasions of this noxious weed. An adjacent landov^Tier 

 wants to graze goats in the vicinity. Fencing and a rest-rotation grazing regime are recommended. 

 Mueggler and Stewart (1980) lump this type with the Artemisia arbuscula/Agropyron spicatum 

 community type. 



Artemisia tridentata ssp. vasyana/Festuca idahoensis plant association 



(ARTTSV/FESIDA; mountain big sagebrush/Idaho fescue; MTNHP rank G4/S4; one plot) 



Environment: This is probably the single most extensive community type in the Ruby Range, 

 especially common in the southern part of the study area at middle elevations with gentle 

 topography and soils weathered from Precambrian basement rock. The two sampled plots are 

 around 7,500 feet elevation, with moderate slopes and southwestern and eastern aspects, but the 

 type extends over many aspects and gradients. Surrounding higher elevations, wind-impacted 

 slopes, and burned areas are Festuca idahoensis grasslands. 



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