shrub-dominated environments, management strategies usually favor serai species, regardless of 

 the plant association. In grasslands, conversely, usually the late-seral/climax species are favored, 

 hi the third instance, the misconception is too narrow and we can in fact compare the relative 

 reproductive success of the tree species present with known successional patterns and scrutinize 

 the current undergrowth vegetation to identify the plant association (i.e. habitat type). Where 

 stands have been severely disturbed, are in early serai stages, or at the closed-canopy stage 

 (having depauperate undergrowth vegetation) comparison of the stand with adjacent stands of 

 later serai stages having comparable site factors permits identification of the potential climax 

 vegetation. 



Daubemnire and other western vegetation ecologists, who have developed classifications for 

 various geographic and geopolitical entities, have paid scant attention to defining the higher level 

 strata of what is a hierarchical system. However the Nature Conservancy hierarchical 

 classification system, derived a modification of the UNESCO system Driscoll et al. 1973), is 

 well-developed and represents a potential national vegetation classification. Currently it is being 

 reviewed by a committee of the Vegetation Ecology Section of the Ecological Society of 

 America. The floristically-defined vegetation units we have employed fit into the next higher 

 levels (Formation and Group, essentially defined by physiognomic characteristics) of the Nature 

 Conservancy classification. 



The current Nature Conservancy hierarchical vegetation classification does not superscede that of 

 Daubemnire but provides an overarching hierarchy, as well as recognition of recun-ent serai 

 assemblages, or community types (ct.). in addition to the climax plant associations (p. a.) as 

 presented for Montana in "A preliminary vegetation classification of the western United States" 

 (Bourgeron and Engelking 1994). 



The following sketches of study area plant associations and community types are arranged by 

 decreasing stature of lifeform and alphabetically within lifeform; the baiTcns and wetland types 

 are broken out separately due to the uniqueness of their enviromiients. Description is provided of 

 the accompanying environment, soils, and vegetation. 



Within the vegetation section, in addition to giving a quick characterization of composition, a 

 comparison between the study area occurrence of the type and other representations of the type 

 im-oughout the state and western U. S. is made. The constancy-cover tables are useful for 

 comparing the expression of community t>'pes on the study area to the named tj'pe as it occurs 

 elsewhere. Local expressions in composition are readily appreciated in these comparisons. Two 

 reports that present a preliminary regional synthesis of plant associations/communities across all 

 lifefonns and environments and have dichotomous keys useful for identifying the vegetation 

 types are "Plant communities of northeastern Montana: A first approximation" (DeVelice 1995) 

 and "Classification of southwestern Montana plant cominunities: Emphasizing those of Dillon 

 Resource Ai-ea, Bureau of Land Management" (Cooper et al. 1995). These publications can be 

 consulted as conceptual models and teclinical references to the various vegetation units on the 

 study area landscape. 



