Juniperus scopulorum/Aqropyron spicatum Community Type (Jusc/Aqsp c.t.) 

 The Jusc/Agsp c.t. is a minor type in the study area, is found mainly in the 

 vicinity of Fort Peck on cool aspects and on grey-black soils often derived 

 from shale. Like other tall shrub types, it provides important wildlife 

 cover. Brown (1971) identified a Juniperus-Aqropyron community in badlands 

 on clayey soils with low sodium content. Similar communities can be found 

 in Montana on a variety of substrates (See for example, DNRC 1976). 



The Jusc/Agsp c.t. shares some subordinate species with the Juho/Ansc- 

 Agsp c.t. Other distinctive associates are Melilotus officinalis , Comandra 

 umbel lata , Solidaqo missouriensis , Achillea millofolium , Chrysopsis villosa , 

 Artemisia tridentata , Juniperus communis , Rosa spp. , and Prunus yirginiana . 

 Artemisia" frigida was present in all stands. Species diversity is quite high, 



Artemisia cana/Aqropyron smithii/Bouteloua gracilis Community "lype 

 (Arca/Agsm/Bogr c.t. "7T The Arca/Agsm/Bogr c.t., is found in areas with the 

 auove average moisture and is associated with a low slope position. It is 

 important to a variety of animal species. Productivity is noticeably higher 

 than for adjacent grassland types. Cattle grazing may favor A. cana , but 

 heavy sheep grazing can result in a decrease of this species. Houston (1961) 

 noted that light stocking of livestock can favor A. cana abundance. 



Species diversity values suggest that this type and the Artr/Agsm/Bogr 

 c.t. involve more than the addition of a shrub, Artemisia , to the Agsm/Bogr 

 c.t. The sites involved may permit a richer flora, or it may be that the 

 presence of a slirub layer provides special niches for other species. 



The frequent presence of Achillea mi 11 Of ol ium , Ratibida columnifera , and 

 Symphoricarpos occidental is supports the hypothesis that this community type 

 is associated with above average moisture. Gaura coccinea was sometimes 

 present. 



Artemisia cana/Stipa viridula Aqropyron smithii Community Type (Area/ 

 Stvi-Aqsm c.t. ) . The relation of this type to the Arca/Agsm/Bogr c.t. is 

 similar to the relationship of the Stvi -Agsm/Bogr c.t. to the Agsm/Bogr c.t. 

 It might be considered a phase of the Arca/Agsm/Bogr c.t. occurring under an 

 above average moisture regime and light-moderate livestock use. 



The Arca/Stvi-Agsm c.t. typically contains more moist site indicators 

 than the Arca/Agsm/Bogr c.t. Some understory associates are Artemisia lud - 

 oviciana , Psoralea argophylla , Achillea millofolium, Poa canbyi , Ratibida 

 columnifera , and Symphoricarpos occidental is . 



Artemisia tridentata/Agropyron smithii/Bouteloua qracilis Community Type 

 (Artr/Agsm/Bogr c.t. ). A principal stand distribution of A. tridentata spp. 

 wyominqensis lies on the western edge of the study area (Morris et al. 1976). 

 The Artr/Agsm/Bogr c.t. is most abundant in the area along and west of High- 

 way 24. 



The Artr/Agsm/Bogr c.t. is found mainly on uplands, in contrast to the 

 Arca/Agsm/Bogr c.t. A. tridentata spp. wyomingensis may be intolerant of 

 high soil moisture. Neither A. smithii nor B^. gracilis has 100% constancy 

 for this type and occasionally upland grasses such as Stipa comata are among 

 the dominants. Aristida longiseta and Selaginella densa may be present. 



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