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8. Population ecology of the taxon. 



A. General summary: Shoshonea pulvinata occurs in sparse 

 vegetation of open or occasionally partially shaded fellfield- 

 like habitats. The species is probably intolerant of intense 

 competition and full shade. In the Pryor Mountains in Montana, 

 subpopulations occur in narrow belts along the windward rims of 

 canyons. In the Beartooth Mountains, subpopulations occupy 

 larger, windswept ridgetop areas. Although large grazing 

 animals such as wild horses or mountain sheep may preferentially 

 use these communities during the winter when they are more free 

 of snow cover than adjacent areas, no evidence of grazing damage 

 was observed. 



B. Positive and neutral interactions: None known. Most species of 

 herbaceous vascular plants have mycorrhizal associations with 

 fungi in the Family Endogonaceae (Gerdemann 1968). 



C. iviegative interactions. 



1. Herbivores, predators, pests parasites and diseases: None 

 known. At the Grove Creek Pinnacles site in the Beartooth 

 Mountains, at least two species of swallowtail butterflies 

 (Family Papilionidae) were observed. Larvae of many 

 butterflies in this family are specialized feeders on 

 plants in the ApiaceaeJ however, no herbivore damage to 

 Shoshonea plants was observed during the surveys. 



5. Competition. 



a. Intraspecif ic: In most cases, Shoshonea pulvinata 

 plants are widely spaced. Although above-ground 

 interference is probably not important, competition for 

 nutrients and water may be occurring. 



b. Interspecific: Shoshonea occurs only in areas with 

 relatively sparse vegetation cover and appears to be 

 intolerant to shading, indicating that it is probably a 

 poor competitor. Based on its growth form and habitat 

 preferences, Shoshonea would probably be considered a 

 stress tolerator, sensu Grime (1982). These species 

 are generally poor competitors. The observations 

 indicate that the shade and litter created by a forest 

 overstory may also have a negative effect on Shoshonea 

 plants. 



3. Hybridization. 



1. Naturally occurring: None known. 



2. Artificially induced: None known. 



3. Potential in cultivation: Unknown. 



