SEl/4) and compared the vegetation to that outside the fence. 

 Cover of unpalatable forbs, Balsamorhiza saqittata , Phlox hoodii , 

 Oxytropis campestris , Taraxacum officinale and Ziqadenus 

 venenosus , was higher outside the exclosure. Height of native 

 grasses inside the exclosure was approximately twice that on the 

 outside. Both livestock and feral horse grazing increase the 

 likelihood of exotic weed encroachment. Degradation of subalpine 

 grasslands can be ameliorated by lowering stocking rates. Damage 

 done to the desert ecosystem at lov/er elevations suggests that 

 these fragile systems are not compatible with feral horse 

 grazing. 



ORV Use 



At the present time there is relatively little off-road 

 vehicle use in the Pryor Mountain Desert area. However, the 

 topography and sparseness of the vegetation is appropriate for 

 this sort of recreation. ARTPED-ATRNUT, ATRNUT-ARTSPI , 

 ATRNUT/MONNUT and CHR.NAU/ERIBRE are dominated by low shrubs and 

 have sparse vegetation. These habitats will be especially 

 vulnerable to disturbance caused by ORV use, particularly 

 destruction of vegetation, soil compaction and increased erosion. 

 The arid climate prohibits rapid recovery of vegetal cover and 

 soil stability. 



MinincT 



Bentonite claims have been made on public lands in the Pryor 

 Mountain Desert area, and some strip mining has occurred on both 

 sides of the Wyoming border. The Atriplex nuttallii / Monolepis 

 nuttalliana and Artemisia pedatif ida - Atriplex nuttallii community 

 types are often associated with bentonite deposits and strip 

 mining has the potential for disturbing or destroying large areas 

 occupied by these rare plant communities. Oil and gas 

 development has occurred south and west of Warren. Drilling and 

 the associated road-building and development could degrade or 

 destroy portions of rare plant communities. Introduction of 

 exotics is a potential problem associated with development in 

 these areas. 



Protecting Biological Diversity 



Plant communities that are at risk due to their rarity or 

 other aspects of their biology should be given high priority for 

 protection (Jenkins 1981) . Based on the results of our study, 

 vegetation types occurring in the study area can be classified 

 into one of three groups based on global and state rarity and 

 degree of threats: (1) globally rare - Gl, G2 or G2 , (2) globally 

 uncommon - G3 , and (3) relatively common. Knowledge of the 

 distribution of plant communities in groups (1) and (2) in the 

 Pryor Mountain Desert can be used to identify areas that are 



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