DistJchlis stricta Community Type (Dist c.t.) . The Dist c.t. may be 

 a near monoculture. Occasionally other salt tolerant grasses such as Puc- 

 cinellia nutalliana , Poa j unci folia . Spartina gracilis , or Muhlenbergia 

 asperi folia in small amounts. In some communities, P. j unci folia may be 

 co-dominant, but its abundance appears to be related to soil disturbance. 

 The Dist C.T. occurs on alkali bottoms near water courses. Dist c.t. ap- 

 pears to be similar to the Distich! is stricta communities of Ungar (1974) 

 and Dodd and Coupland (19667! 



The transition from the Dist c.t. to mixed prairie communities may be 

 abrupt or gradual. If gradual, coenoclinal associates of D. stricta are 

 A gropyron smithii and some bluegrasses, including Poa j unci folia , P_. Scab - 

 reVU, and possibly £. gracillima ,* although the latter species would seem 

 to be off-site. The proposed mine area contains some bottomland that was 

 plowed over thirty years ago and now has a community of D. stricta, A. 

 smithii , Poa spp . , and to a lesser extent Bromus tectorum , Plantago "spp . , 

 and some memBers of the Cnenopodiacae family. An identical community could 

 not be found outside the mine area and so a D. stricta - A. smithii community 

 was sampled for productivity. Dodd and Coupland (1966) identified a Distichlis- 

 Agropyron community, and Smoliak et al. (1976) identified a type dominated by 

 A. smithii , D^. stricta , Artemisia cana , and Sarcobatus vermiculatis . 



D. s tricta can be found with the typical prairie species in areas of 

 gradual transition, progressing outward from the Dist c.t. D. stricta can 

 act as an increaser species in some situations. 



The occasional occurance of D. stricta in badlands should not be con- 

 fused with the Dist c.t., which occurs in lowland saline areas. 



Bouteloua gracilis Community Type (Bogr c.t. ). The Bogr c.t., seems 

 to be a grazing disclimax on a number of sites. Soil texture ranges from 

 loams to silty clay loams. Field observations suggest that parent community 

 types can be Bouteloua gracilis/Agropyron smithii community type (Bogr/Agsm 

 c.t. ) , the Agropyron spicatum/Bouteloua gracilis - Carex fili folia community 

 type (Agsp/Bogr-Cafi c.t.), and to a lesser extent other types. Poa sand- 

 berg ii is commonly present in this community type. 



Carex filifolia and B.. gracilis dominated a few reconnaissance plots 

 which may represent a severe grazing disclimax on sites once dominated by 

 Stipa comata . The loss of S_. comata due to grazing seems to be rare, how- 

 ever, and sheep appear to favor C_. filifolia . 



B^. tectorum and B^. japonicus are absent or very rare even on the most 

 heavily grazed areas. Although this results from the precipitation pattern, 

 the species can prosper on abandoned cultivated land, suggesting that soil 

 disturbance is involved. 



* Hitchcock (1951) notes, "There are several groups of Poa that present 

 many taxonomic difficulties." One of the groups cited as an example is 

 Scabrellae , which contains P^. scabrella , P^. gracillima , P^. secunda , and P. 

 canbyi . Hitckcock et al .(1959), in referring to Poa, notes "Taxonomically, 

 the genus is notoriously difficult, particularly because many of the species re- 

 produce in large measure by other than true sexual means..." They note that due 

 to the high variability involved, keys must accomodate exceptions under more 

 than one lead. They discuss further problems in identifying reliable characters 

 in the P^, sandbergii complex. 



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