rhizomatous species that might be able to 

 outcompete Carex spp. in a meadow turf 

 environment . 



b. Herbivory: I observed no evidence of insect 

 herbivory on Carex parryana ssp. idahoa 

 during field surveys in 1997, and saw no 

 evidence of insect damage on ca. 15 herbarium 

 specimens housed at the University of Montana 

 (MONTU) . 



Cattle grazing occurs at nearly all of the 

 known sites for Carex parryana ssp. idahoa in 

 Montana and Idaho. In 1997 grazing intensity 

 varied from ungrazed to ca. 100% utilization 

 at the sites surveyed. Experimentation is 

 the only robust way to determine the effects 

 of livestock grazing on this sedge, and these 

 studies have not been done. 



In 1997 Lesica estimated canopy cover of 

 dominant plant species and abundance of 

 flowering stems of Carex parryana ssp. idahoa 

 at fourteen sites in Montana (Appendix D) . 

 Graminoid cover was high at all sites. There 

 was a strong positive relationship between C. 

 parryana ssp. idahoa and graminoid cover and 

 strong negative relationship between the 

 sedge and a number of species that are 

 thought to increase with livestock grazing, 

 Poa pratensis, Antennaria microphylla and 

 Aster occidentalis . These observations 

 suggest that Carex parryana ssp. idahoa 

 behaves like a typical palatable graminoid, 

 persist with moderate ungulate grazing 

 pressure, decreasing as grazing becomes 

 strong enough to cause an increase in forbs 

 and Poa pratensis. Indeed Hermann (1970) 

 reports that C. parryana ssp. idahoa provides 

 excellent forage for cattle and horses but is 

 too rare to be of more than local importance. 



c. Other biotic interactions: Much of the 

 habitat that could support populations of 

 Carex parryana ssp. idahoa on private land is 

 mowed for hay. The effects of annual mowing 

 on this plant are not known. 



2. HYBRIDIZATION: Subspecies parryana and ssp. 

 idahoa occur together at ca. six of the sites 

 surveyed in 1997. Subspecies parryana was often 

 in slightly drier and often more saline habitats 



15 



