This file was created by scanning the printed publication. Errors identified by the software have been corrected; however, some errors may remain. Grassland and shrubland habitat types of Western Montana W. F. Mueggler and W. L. Stewart USDA Forest Service General Technical Report INT-66 INTERMOUNTAIN FOREST AND RANGE EXPERIMENT STATION Forest Service, U.S. Department of Agriculture USDA Forest Service General Technical Report INT-66 January 1980 Gras$land and shrubland habitat types of Western Montana w. F. Mueggler and W. L. Stewart INTERMOUNTAIN FOREST AND RANGE EXPERIMENT STATION Forest Service U.S. Department of Asriculture Ogden, Utah 84401 THE AUTHORS WALTER F. MUEGGLER, Principal plant Ecologist for the Intermountain Station, spent 13 years conducting research on western Montana mountain rangelands. He is currently Leader of the Aspen-Moun­ tain Grassland Ecology Research Work unit at Logan, Utah. He obtained his B.S. degree from the university of Idaho, M.S. degree from the University of Wisconsin, and ph.D. degree in Plant Ecology from Duke University. WILLIAM L. STEWART, now Regional Pesticide Specialist, USDA Forest Service, Northern Region, spent 3 years as a Range Conserva­ tionist in southwestern Montana. For two of those years he assisted in the development of the classification of and management implications for western Montana grasslands and shrublands. He obtained his B.S. and M.S. degree from Washing­ ton State University, and currently is working on a Ph.D degree at Washington State University. ACKNOWLEDGMENT Major support for this study was provided by the Northern Region of the Forest Service, U. S. Department of Agriculture, through a cooperative agreement with the Intermountain Forest and Range Experi­ ment Station. W. P. Handl, formerly Range Scientist with the Intermountain Station, participated in collecting field data, adapting computer programs, analyzing data, and developing the classification. Drs. G. A. Nielsen and L. C. Munn, Montana State University, supplied soil analyses. Research assistants participating in field sampling included Rick Miller, Rick Young, Mike McGinnis, Bob Yeager, and Wayne Leininger. RESEARCH SUMMARY A classification system is presented for the grasslands and shrublands of the mountainous western third of Montana. The classi­ fication utilizes the habitat type concept and is based upon potent­ ial natural vegetation. Data on plant species and environment from 580 relatively undisturbed stands were analyzed to form the classi­ fication. Twenty-nine habitat types occurring in 13 climax series are defined and described. A diagnostic key utilizing indicator plant species is provided for field identification of the habitat types. Vegetation composition, distribution, and environment of each habitat type are described in the text. Tables are provided for detailed comparisons. Management related information on forage productivity, composition changes with grazing, and range manage­ ment practices is summarized for each type. CONTENTS Page INTRODUCTION • 1 CONSIDERATIONS . 2 KEY TO HABITAT TYPES . 5 TYPE DESCRIPTIONS AND MANAGEMENT IMPLICATIONS 10 Stipa comata/Bouteloua gracilis h.t. 10 Agropyron spicatum/Bouteloua gracilis h.t. 14 Agropyron spicatum/Agropyron smithii h.t. 18 Agropyron spicatum/Poa sandbergii (MONT) h.t ..... 21 Festuca scabrella/Agropyron spicatum h.t. 23 Festuca scabrella/Festuca idahoensis h.t. 27 Festuca idahoensis/Agropyron smithii h.t. 30 Festuca idahoensis/Agropyron spicatum h.t. 32 Festuca idahoensis/Agropyron caninum h.t. • .. 38 Festuca idahoensis/Carex filifolia h.t. .. 41 Festuca idahoensis/Stipa richardsonii h.t. .... 42 Festuca idahoensis/Deschampsia caespitosa h.t. 44 Deschampsia caespitosa/Carex spp. h.t. 45 Artemisia arbuscula/Agropyron spicatum h.t. 47 Artemisia arbuscula/Festuca idahoensis h.t. .... 49 Artemisia tridentata/Agropyron spicatum (MONT) h.t. 50 Artemisia tridentata/Festuca scabrella h.t. 54 Artemisia tridentata/Festuca idahoensis (MONT) h.t. 55 Artemisia tripartita/Festuca idahoensis (MONT) h.t. 58 Potentilla fruticosa/Festuca scabrella h.t. 60 Potentilla fruticosa/Festuca idahoensis h.t. 62 Purshia tridentata/Agropyron spicatum (MONT) h.t .. 64 Purshia tridentata/Festuca scabrella h.t. • •.. 66 Purshia tridentata/Festuca idahoensis (MONT) h.t .. 67 Cercocarpus ledifolius/Agropyron spicatum h.t. 69 Rhus trilobata/Agropyron spicatum h.t. .•. 71 Rhus trilobata/Festuca idahoensis h.t. ... 72 Sarcobatus vermiculatus/Agropyron smithii h.t. 73 Sarcobatus vermiculatus/Elymus cinereus h.t. 74 OTHER VEGETATION TYPES 75 PUBLICATIONS CITED . 77 APPENDIX A--METHODS. 85 APPENDIX B--WESTERN MONTANA ENVIRONMENT. 91 Topography and Geology •. 93 Soils .• ...••.. 94 Climate • • . • . • • 94 APPENDIX C--ENVIORNMENT PARAMETERS FOR IMPORTANT HABITAT TYPES .• 97 C1.--Genera1. 99 Page C2.--Soil Physical Properties 100 C3.--Soil Chemical Properties. 102 APPENDIX D--COVER CLASS SU~~RIES BY HABITAT TYPES 103 APPENDIX E--SPECIES CONSTANCY AND CANOPY COVER BY HABITAT TYPE 107 El.--Stipa comata Series .. 109 E2.--Agropyron spicatum Series. 110 E3.--Festuca scabrella Series. 113 E4.--Festuca idahoensis Series. 116 E5.--Deschampsia caespitosa Series. 120 E6.--Artemisia arbuscula Series .• 121 E7.--Artemisia tridentata Series ...... 123 E8.--Artemisia tripartita Series .. 126 E9.--Potentilla fruticosa Series ..... 127 El0.-Purshia tridentata Series .. 130 Ell.-Cercocarpus ledifolius Series .. 132 E12.-Rhus trilobata Series ..... 133 E13.-Sarcobatus vermiculatus Series. 135 APPENDIX F--PALATABILITY RATINGS . • . 137 APPENDIX G--COMPARISONS OF DIFFERENTIALLY-GRAZED PAIRED STANDS • 141 Gl.--Stipa comata Series .• 143 G2.--Agropyron spicatum Series. 144 G3.--Festuca scabrella/Agropyron spicatum h.t. 146 G4.--Festuca scabrella/Festuca idahoensis h.t. 148 G5.--Festuca idahoensis Series ...•... 150 G6.--General Description of Paired Stands 152 INTRODUCTION The highly varied environment of the Northern Rocky Mountains creates a mosaic of forest, shrubland, and grassland vegetation. Species composition and productivity, and the consequent potential values, differ greatly between and within these major vegetation types. The ability to identify land units and relate them to both their inherent capability to produce various resources and their response to management activities is essential for multiple use planning and intensive resource management on our western wildlands. The need to classify vegetation types and land units has long been recognized by natural resource managers. It is reflected by the development and use of numerous forest and range type classifications during the past fifty years. Unfortunately, such classifications have tended to stress current site occupancy and identity by a few commercially important plants. Little consideration has been given to the successional status of the existing vegetation or to the potential productivity of the environment as reflected by the "climax" vegetation. In the past decade, the habitat type concept of environmental classification developed by Daubenmire (1952) has gained increasing acceptance in the West, particularly by forest managers. This concept stresses use of the entire climax plant community as an environmental integrator, thus permitting identification of environments (habitats) with similar biotic potentials. All environments with the potential to support approx­ imately the same kind of stable (climax) mix of plant species are considered to be within the same habitat type regardless of current successional status. This approach to classification has been used successfully to classify both forest vegetation (Daubenmire and Daubenmire 1968; Pfister and others 1977) and grassland-shrubland vegetation (Daubenmire 1970) in the Northwest. This type of classification provides the framework essential for organizing information on resource potentials, limitations, and responses to management activities. Forests and rangelands of Montana, Idaho, and Washington are being mapped into site potential units (habitat types) so that informa­ tion on each habitat type can be more widely applied. Development of habitat type classifications for nonforested wildland has progressed more slowly than that for forested land. The need to develop such a classification for the nonforested lands of western Montana prompted a cooperative study between the Forest Service's Northern Region and Intermountain Forest and Range Experiment Station. The results of that study are reported here. The purpose of this study was three-fold: (1) to develop a habitat type classification scheme for the grasslands and shrublands of the mountainous western third of Montana (fig. 1); (2) to describe as well as is currently ..... , possible those characteristics of each habitat type that would be useful to the resource manager for developing management practices; and (3) to provide a framework for further management-oriented research. Meeting the first objective required extensive sampling of relatively undisturbed grasslands and shrublands throughout western ~lontana and developing a classification based on similarities of the vegetation. The second objective was met by a combination of companion studies on vegetation productivity and soils, and by a synthesis of infor­ mation found in a thorough review of publications and reports. This information was then related to the habitat types identified. The resulting classification identifies the basic land units to which future research can be tied, thus fulfilling the third objective. 1 CARTER POWDER