INTRODUCTION 



This study provides a classification of plant communities in 

 southwestern Montana. The emphasis was on locating and describing 

 rare or previously undescribed communities and common communities 

 in good to excellent ecological condition on selected BLM lands in 

 the Headwaters and Dillon Resource Areas. The comprehensive class- 

 ification was based on the integration and synthesis of both 

 existing data and newly sampled plots. This classification will be 

 useful in identifying sensitive communities and natural areas where 

 management activities may need to be adjusted to maintain habitat 

 values. Additionally, the classification provides a reference 

 system for baseline monitoring of environmental impacts and vegeta- 

 tion recovery and provides an ecological basis for categorizing 

 environmental variation. 



This work represents a step towards developing a comprehensive 

 classification of Montana plant communities that will provide land 

 managers and scientists a state-wide perspective of community 

 variation (nation-wide when correlated with other state classifica- 

 tions) . Such a perspective is invaluable towards making sound 

 management prescriptions and predictions, designing and inter- 

 preting experiments, and identifying areas of critical importance 

 for conservation. 



This document is divided into three volumes: Volume I 

 provides text describing previous research, the study area, the 

 methods used, and results of this study. Volume II provides 

 appendices containing detailed plant community and site data 

 recorded during this study. Volume III provides close-up and 

 aspect photographs from each site, referenced by plot numbers. 



ACKNOWLEDGEMENTS 



The author gratefully acknowledges the financial assistance 

 provided by the USDI Bureau of Land Management and the Montana 

 Natural Heritage Program. Additionally, Bureau of Land Management 

 assistance in locating and assessing some of the field sites was 

 greatly appreciated. 



The author appreciated the assistance provided by Peter Achuf f 

 and Alistair McAlpine during the initial stages of fieldwork. 

 Peter Achuf f and Lisa Roe provided invaluable assistance in voucher 

 specimen identification. Finally, appreciation is extended to 

 Margaret Beer, Cedron Jones, and Diana Schwab for their conscien- 

 tious assistance in data entry and data quality control. 



