26. Artemisia tridentata / Atrip lex nuttallii c.t. 



(ARTTRI/ATRNUT; big sagebrush/Gardner saltbush) 



(2 stands) 



Environment- This minor type occurs on slopes, terraces and 

 alluvial fans in highly eroded terrain on the south side of the 

 Pryor Mountains. Elevations range from 4,300 to 4,800 feet 

 Adjacent communities include ARTTRI/AGRSPI and sparse Utah 

 juniper woodlands. 



Vegetation- Artemisia tridentata and Atriplex nuttallii occurred 

 in both stands with cover of 15% and 10% respectively. 

 Gutierrezia sarothrae also occurred in both stands but cover was 

 sparse. Grass cover is very sparse; no species is present in all 

 stands or has more than 1% canopy cover. The scarcity of grasses 

 is likely due to livestock grazing. Aqropyron spicatum , 

 Oryzopsis hymenoides , and Stipa comata would probably be the 

 dominant grasses in undegraded stands. The exotic Haloqeton 

 qlomeratus and Opuntia polyacantha are the only common forbs. 

 Lichens are abundant in stands with a gentle slope. 



Soils- ARTTRI/ATRNUT occurs on deep to very deep soils derived 

 from shale, sandstone and alluvium. Gravel and cobbles are 

 abundant in some stands but absent in others. The soil subgroup 

 at our single soil characterization site was a Ustic 

 Torriorthent. Texture of the surface horizon is silty. 

 Carbonates were present throughout all horizons in the single 

 stand sampled. pH was 6.8 and 1925 uhmos/cm^, one of the highest 

 measurements recorded, suggesting that soils are highly saline (1 

 stand) . 



Other Studies- This community type would likely be included in 

 Knight et al.'s (1987) saltbush desert shrubland. ARTTRI/ATRNUT 

 is not reported from outside the northern Bighorn Basin. Fautin 

 (1946) described communities dominated by Atriplex conf ertif olia , 

 Artemisia spinescens , and Oryzopsis hymenoides from west-central 

 Utah. 



Natural Heritage Program Rank- G2/S2 



27. Atriplex nuttallii / Monolepis nuttalliana c.t. 



(ATRNUT/MONNUT; Gardner saltbush/povertyweed) 



(3 stands) 



Environment- Low ridges and toeslopes in badlands near the 

 Wyoming border are often occupied by ATRNUT/MONNUT. Elevations 

 range from 4,500 to 4,800 feet, and slopes are usually gentle but 

 show evidence of sheet and gully erosion. Adjacent communities 

 are generally dominated by Atriplex nuttallii or Artemisia 

 pedatif ida. 



29 



