set up in broken topography that did not necessarily represent a uniform environment for vegetation 

 sampling. 



Soil samples (top 1 dm) were collected from each plot. To stretch the budget farthest, the most 

 detailed soils test were run on the samples from the most uncommon vegetation types or vegetation 

 types thought to be strongly associated with soils (e.g. acid shales or salt affected soils). For 

 common vegetation types, ostensibly having no particular associations with substrate, only pH and 

 conductivity, were assigned. Where vegetation types were suspected to be linked to soil 

 characteristics or the literature indicates such to be the case, tests were assigned on a sample-by- 

 sample basis. For example, the Stipa comata - Carex filifolia plant association is reported to occur 

 on coarser textured, circumneutral soil, so texture analysis and pH tests were apportioned to many of 

 the samples characterized as being from this vegetation type. All soil testing was performed by the 

 Montana State University Soil Testing Laboratory in Bozeman. 



The vegetation data set was analyzed using the STRATA program of EC ADS. (Ecological 

 Classification and Description System), a USDA Forest Service ecological sampling package 

 revised from the previous ECODATA program (Cooper et al. 1995). Plots were subjectively placed 

 in plant association or community types based on selection criteria (relative homogeneity, optimal 

 condition and development, nominal exotic species component) also considering similarity to types 

 described in the literature. 



Synthesis and cover/constancy tables (Appendix A) were generated after data entry for each type. 

 The tables utilize 6 letter acronyms to designate plant species. These are generally the first three 

 letters of the genus name followed by the first three letters of the specific epithet, thus Pascopyrum 

 smithii is indicated as PASSMI. In a few cases, modem synonymy has not been incorporated into 

 database tables utilized by E.C.A.D.S. and acronyms for older names must be used in the 

 constancy/cover tables. Sometimes accurate identification of species in the plots was difficuh or 

 impossible and acronyms represent determination only to the level of genus or life category. A 

 complete listing of acronyms and the scientific names they indicate is provided in Appendix B. 



Results are presented in a framework consistent with national classification standards adopted by 

 federal agencies that include the BLM. The rationale and structure behind them is described by the 

 Federal Geographic Data Committee (1997) and the Ecological Society of America - Vegetation 

 Classificafion Panel (Loucks et al.l997). This is being used, e.g., in the USGS Gap Analysis 

 Program (GAP) for mapping vegetation of the United States in order to assess the conservation 

 status of wildlife species and their habitats. At lower levels of classificafion, most units of the 

 Alliance and Plant Association levels of the classificafion have been crosswalked between western 

 states, but the definitions of these two floristic levels are still under discussion. 



We have placed all our floristically defined units (alliances, plant associations, and communities) 

 within the physiognomic units of the National Classificafion and provided a key to these upper 

 levels. There is still no unanimous definifion of the floristic levels, alliance and plant associafion 

 (Loucks 1998). We were not able to generate keys to these levels because of this and the limited 

 informafion from eastern Montana in general. Standardized delimiting criteria and keys are needed in 

 order for users of the classificafion to unambiguously and consistently key to the same taxonomic 

 unit. 



