32 



A representative list of associated species includes the following: 



Agropyron spicatum 

 Allium textile 

 Artemisia nova 

 Art ernes ia trident at a 

 Aster scopulorum 

 Chrysopsis villosa 

 Chrysothamnus nauseosus 

 Festuca idahonis 

 Leptodactylon piingens 

 Lupimis argenteus 

 Opuntia polyacantha 

 Oryzopsis hymenoides 

 Phacelia linearis 

 Phlox longifolia 

 Poa secimda 

 Stipa comata 



The soil substrates vary greatly. In the study area, they are derived from limestone, diabase and 

 other volcanic materials, and from basin sediments, most often as stony loams but also including 

 clayey and gravelly soil textures. 



POPULATION INFORMATION: Population numbers range from <50 to >5000 plants. Two 

 of the three large populations (>5000) in Montana are in the study area, located north of 

 Henneberry Ridge (#017), and in the Coal Creek headwaters area (#016). 



Reproduction is by seed and the species is relatively long-lived. It can go dormant through entire 

 growing seasons (Lesica and Steele 1994), an adaptation which confounds population size and 

 trend estimates. The cool, moist conditions early in the 1995 growing season appeared to have 

 favored it. Previously documented populations were revisited in 1995; observed numbers were 

 high. 



MANAGEMENT CONSIDERATIONS: This highly palatable species is grazed in preference 

 to Agi-opyron spicatum (P. Lesica pers. obs.). High stocking rates and repeated spring grazing 

 will eliminate fruit production and thus, the population's ability to sustain itself over the long 

 term. Monitoring oi Astragalus scaphoides under different grazing regimes has suggested that A. 

 scaphoides can persist if predation is moderate, or absent during some years, as with rotation 

 grazing (Lesica 1995). 



The current study and favorable growing season afforded an opportunity to independently study 

 distribution of Astragalus scaphoides across the landscape in relation to management activities. 

 The largest Montana populations of this species are north and south of Grasshopper Creek in 



