Coverage data . Each plot was examined closely and all species present 

 were recorded. Plants were identified to species except for mosses, which 

 were simply listed as mosses, and lichens, which were identified simply as 

 crutose, foliose, or ephphytic. Species not readily identifiable were col- 

 lected along with a card indicating plot number, and an identifying letter 

 if more than one unknown was collected from a single plot. 



After all species were listed, the plot was further examined and the 

 coverage of each species, as well as tne coverage of litter, bare soil and 

 bare rock was recorded using cover classes (after Daubenmire, 1959), with a 

 trace category for species having less than one percent coverage. Dauben- 

 mire, (1959, 1968) and Bannister (1966) note the effectiveness of using 

 coverage to concisely express some important attributes of the species in a 

 community. Appendix C addresses problems associated with quantitatively 

 measuring the presence, but not absence of species. 



Productivity Data 



After classification, the major community types of the proposed mine 

 area, which was revised to 11.5 square miles (29.8 km^), were identified. 

 Thirteen major community types were recognized. Exclosure locations for 

 these types were identified by finding relatively homogeneous stands of 

 vegetation which were similar to the community type as characterized on the 

 Constancy and Average Coverage tables (Appendix A). The tentative exclosure 

 sites were visited by Dennis Hemmar of the Department of State Lands, and 

 Dr. Jack Taylor of Montana State University. The thirteen most suitable 

 sites were chosen and exclosure boundaries were staked by the Department of 

 Natural Resources and Conservation (DNRC) staff. 



Exclosures were constructed of steel fence posts with wood posts for 

 corner and gate braces prior to any livestock grazing in spring 1977. 

 Fencing consists of woven wire with two strands of barbed wire on top. With 

 one exception, each exclosure has two gates at opposite ends of the enclosure. 

 The gates can be left open to allow grazing in the exclosure to prevent suc- 

 cession away from community type species composition. All exclosures are 

 over one acre in size with the exception of the Distichlis stricta community 

 type exclosure. 



A grid was superimposed on the exclosure and numbered reference stakes 

 for each row were placed at the fence. Plot locations were selected using 

 random numbers. Numbered stakes identified the plots that were to be clipped. 

 Exclosures were divided normal to the contours into two replicates so that 

 they could be tested for homogeneity. 



2 

 Twenty-three to twenty-five 5.38 square feet (0.5 m ) circular plots 



were clipped in each exclosure. A Montana State University clipping crew 



clipped six exclosures in late July, consisting of the Distichlis stricta , 



Stipa comata/Bouteloua gracilis - Carex filifolia , Agropyron spicatum/ 



Bouteloua gracilis - Carex filifolia , Bouteloua gracilis - Carex filifolia/ 



Stipa comata community types and Distichlis stricta - Agropyron smithii 



ecotone exclosures. Cool season dominants characterize these communities. 



The seven remaining communities were expected to reach peak productivity 



