Appendix D. 



Habitat and Grazing Response 

 of Carex parryana ssp. idahoa in Montana 



Peter Lesica 



929 Locust 



Missoula, Montana 59802 



November 1997 



Introduction 



Carex parryana ssp. idahoa is a sedge found in moist 

 subirrigated meadows of southwest Montana and adjacent Idaho. 

 The plant is considered rare due to its limited habitat and 

 geographic range (Hermann 1970, Lesica and Shelly 1991) . The 

 habitat of Carex parryana ssp. idahoa is used for either hay 

 production or livestock grazing; however, neither the effect of 

 grazing nor haying on the sedge is known. The purpose of this 

 study is to describe the vegetation associated with " Carex 

 parryana ssp. idahoa and use this data to help determine the 

 effects of grazing on this rare species. 



Methods 



Carex parryana ssp. idahoa is known to occur in Beaverhead, ^Ae^^ison, 

 Silver Bow, Powell and Gallatin counties, Montana and Clark, 

 Lemhi and Bannock counties, Idaho (Lesica and Shelly 1991, Murray 

 1969) . It is a rhizomatous sedge occurring along the drier 

 margins of subirrigated meadows associated with gentle stream 

 terraces as well as springs and seeps, in Montana usually at 

 6,000-8,500 ft. Hermann (1970) reported that Carex parryana ssp. 

 idahoa has excellent forage value. 



I located more than 20 populations and subpopulations of 

 Carex parryana ssp. idahoa in Beaverhead County, Montana in early 

 August, 1997. Fourteen of these sites showed little or no 

 indication of grazing and were chosen for my study. At each site 

 I estimated canopy cover of all common vascular plant species, 

 total graminoid species and total forb species to the nearest 5% 

 in a 0.01 ha circular plot subjectively chosen to represent the 

 site where Carex parryana ssp. idahoa occurred. I counted the 

 number of flowering stems of Carex parryana ssp. idahoa in a 100 

 m^ (50 X 2m) belt transect through the center of each population. 

 Number of stems is not the same as number of individuals but was 

 used here as a relative measure of abundance. 



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