Xylorhiza glabriuscnln Nuttall 



SmcKMh Wootly-aster 



NATURAL HERITAGE PROGRAM SI ATUS: G5/S3 



MONTANA STATUS: Sensitive 



GLOBAL DISTRIBUTION: South-central Moniana and western South Dakota, south 

 to Colorado and Utah 



MONTANA DISTRIBUTION: Southern Carbon County 



PRYOR MOUNTAINS DESERT DIS TRIBUTION: Xvlorhiza glahriuscula is common 

 below 1525 m (5000 ft) on the south and svest side of the Pr\'or Mountains. It occurs in 

 clay or sandy clay soils in plant associations dominated by Artemisia pedatifida . A, 

 tridentata and Chrvs(nhamnus nauseosus . 



MANAGEMENT RECOMMENDATIONS: We located 26 populations of X, 

 glahriuscula in the study area, and most ol these were large. This species can usually be 

 found where soils are appropriate. It is common in the study area and should not be 

 given special status on BLM's Miles City District. 



DISCUSSION 



Managcnu-nt Considerations 



Populations of rare plants in the Pryor Mountain Desert are threatened by (I) 

 encroachment of exotic species, (2) livestock and feral horse grazing, (3) off-road vehicle 

 use, and (4) oil and gas development. 



Halogeton gk^meratus is an Asian species that was introduced into arid western 

 North America in 1934. It has since spread throughout much of the arid and semi-arid 

 lands in the western U.S. It is poisonous lo livestock and outcompetes many native 

 species by increasing the salinity of the soil (Sauer 1988). This plant has become locally 

 common in the Pryor Mountain Desert resiion and may be able to displace native plants, 

 especially annuals. 



Livestock grazing throughout most of the study area appeared to be light to 

 moderate due to the lack of water developmenis. However, severe effects of overgrazing 

 were apparent in areas near water, such as Gyp Springs and Bear Canyon. In these 

 areas, populations of rare plants may be llireatened with extirpation by trampling and 

 perhaps by increased erosion resulting from desiiuction of the fragile vegetation. 



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