Mountains. This type is closely related to and often merges with 

 ARTTRI/AGRSPI and ARTTRI/STICOM, but these coinmunities are 

 generally found on better drained or less saline soils. 



Vegetation- This vegetation is characterized by a moderately 

 dense shrub layer ca. 3 feet tall and a sparse ground layer. 

 Both Artemisia tridentata and Atriplex conf ertif olia occurred in 

 all stands and had mean canopy covers of 28% and 4% respectively. 

 Artemisia spinescens , Atriplex nuttallii , Chrysothamnus nauseosus 

 and Sarcobatus vermiculatus are often present. Graminoid cover 

 is low. Aristida purpurea and Stipa comata are common in many 

 stands, and Sporobolus airoides may be abundant. Phlox hoodii 

 and Opuntia polyacantha are the only common and frequent f orbs . 

 Lichens and bryophytes are uncommon. 



Soils- ARTTRI-ATRCON occurs on deep soil weathered from 

 sandstone, often of the calcareous Chugwater formation. Surface 

 gravel is absent, and texture is generally silty. We collected 

 no additional soils data for this type. 



Other Studies- Knight et al. (1987) describe a sagebrush desert 

 shrubland on the Bighorn Canyon NRA that includes our ARTTRI- 

 ATRCON type. Brown (1971) describes a community dominated by 

 Atriplex conf ertif olia and Artemisia tridentata for the badlands 

 of eastern Montana; however, common grasses are different. 

 Similar communities also occur in Oregon and Utah (Bourgeron and 

 Engelking 1992) and probably in Wyoming and Idaho. 



Natural Heritage Program Rank- G4/S4 



23. Sarcobatus vermiculatus - Artemisia tridentata c.t. 



(SARVER-ARTTRI, greasewood-big sagebrush) 



(3 stands) 



Environment- SARVER-ARTTRI occurs along drainages on alluvial 

 terraces. The type occurs from 4,000 to 4,600 feet and is found 

 in the south and southwest portions of the study area. Adjacent 

 upland sites are most often dominated by Artemisia tridentata and 

 Agropyron smithii or A_^ spicatum . 



Vegetation- This community has a relatively dense shrub layer 

 that may be over 6 feet tall. Artemisia tridentata and 

 Sarcobatus vermiculatus occurred in all stands with mean canopy 

 covers of 21% and 30% respectively. Artemisia pedatif ida was 

 common in one stand. Agropyron smithii and Poa sandbergii were 

 the common native grasses with 30% and 7% cover respectively. 

 Lepidium perf oliatum and Opuntia polyacantha are common forbs. 

 The introduced Taraxacum officinale and Bromus tectorum are 

 common in some stands. Lichens and bryophytes are uncommon. 



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