populations undoubtedly occur on private land, 

 especially in the Centennial Valley and upper Big 

 Sheep Creek Valley. 



E. HABITAT 



ASSOCIATED VEGETATION: Carex parryana ssp. Idahoa 

 most often occurs in an ecotonal area at the 

 border of wet meadow vegetation and sagebrush 

 steppe. Thus, plant species from both of these 

 habitats can be found associated with this sedge. 

 Wet meadows are usually dominated by Juncus 

 balticus, Carex nebrascensis, C. aquatilis, 

 Deschampsia cespitosa, and Potentilla fruitcosa. 

 While steppe vegetation is dominated by Artejnlsia 

 tridentata and/or A. tripartita, Festuca 

 idahoensis and Agropyron smithii. Vascular plant 

 species most commonly associated with Carex 

 parryana ssp. idahoa in order of importance are 

 iTuncus balticus, Carex praegracilis, Muhlenbergia 

 richardsonis , Aster occidentalis, Poa pratensis. 

 Taraxacum officinale, Potentilla gracilis and 

 Antennaria microphylla. Graminoid cover is high 

 (60-100%) , while forb cover is usually low to 

 moderate (5-50%) except in overgrazed areas. Bare 

 ground was usually uncommon (mean=8%) as was 

 lichen and bryophyte cover (mean=14%) . 

 Photographs of typical habitat are provided in 

 Appendix B. 



TOPOGRAPHY: Carex parryana ssp. idahoa appears to 

 be restricted to nearly level sites in the high 

 valleys of southwest Montana. It is most commonly 

 found on terraces associated with headwaters 

 streams at elevations greater than 6,000 ft. 

 Small populations may occur lower or along larger 

 streams . 



SOILS AND GEOLOGICAL RELATIONSHIPS: The wetland- 

 riparian habitat of Carex parryana ssp. idahoa. 

 most likely has silty soils with ample organic 

 matter and little or no coarse fragments. Most 

 known Montana populations occur in areas of 

 calcareous parent material (e.g. Madison limestone 

 or Beaverhead conglomerate) ; however, the few 

 populations occurring in non-calcareous regions 

 suggest that this is not an obligate relationship. 

 In wetlands where part of the habitat was saline 

 (as indicated by the presence of Distichlis and 

 Puccinellia) Carex parryana ssp. idahoa occurred 

 only in the non-saline areas, although C. parryana 



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