Grizzly Bear Distribution in Relation to Habitat Areas and Recreational Use : Cabin Creek-Hilgard Mountains by Bonnie Marie Blan
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Grizzly bear distribution in relation to habitat areas and recreational use : Cabin Creek-Hilgard Mountains by Bonnie Marie Blanchard A thesis submitted in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE in Fish and Wildlife Management Montana State University © Copyright by Bonnie Marie Blanchard (1978) Abstract: The distribution of grizzly bears in relation to habitat areas and recreational use in the Cabin Creek - Hilgard Mountains region of southwestern Montana was investigated during 1975 and 1976. The distribution of grizzly bears was determined by ground and aerial sightings, radio tracking, and locations of other grizzly bear sign. The bears qnd their sign were unevenly distributed over the study area with the most observations occurring in Cabin Creek Basin and the least in the Hilgard Mountains. Grizzly bear activity in the study area varied in intensity and distribution between 1975 and 1976. Locations of observations increased in elevation from May through September and were most frequent on south and southwest exposures. Grizzly bears probably selected FEID/AGCA (Importance Value = 25.0) and PIAL-ABLA (I.V. = 20.0) habitat types in the study area out of proportion to their availability. Observations occurred most frequently in the FEID/AGCA type during spring and early summer, and in the PIAL-ABLA type during fall. Timbered and open areas accounted for nearly equal numbers of observations. Grasses and sedges had the greatest overall frequency of occurrence in scats and were the most important foods during spring. Whitebark pine nuts were the predominant fall food. Recreational use was concentrated in the Hilgard Mountains during July and August. Hiking was the predominant method of travel, and average recreational use consisted of three people staying three days. Few recreationists left the trails, and the majority of human-grizzly encounters occurred while the person was on the trail. Most grizzly bears responded to the presence of humans by fleeing. The majority of registered recreationists placed a high "value" on the existence of grizzly bears in the study STATEMENT OF PERMISSION TO COPY In presenting this thesis in partial fulfillment of the re quirements for an advanced degree at Montana State University, I agree that the Library shall make it freely available for inspection. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by my major professor, or, in his absence, by the Director of Libraries. It is understood that any copying or publication of this thesis for financial gain shall not be. allowed without my written permission. Signature ' I fth cAan & Date hfou-PM hj/w *7, I * 7 _____ GRIZZLY BEAR DISTRIBUTION IN RELATION TO HABITAT AREAS AND ■' RECREATIONAL' USE: CABIN CREEK - HILGARD MOUNTAINS by Bonnie Marie Blanchard A thesis submitted in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE in Fish and Wildlife Management Approved: Chairperson, Graduate Committee ' AA /[ Jtxi 4 l / \ . ead, Major Department MONTANA STATE UNIVERSITY Bozeman, Montana August, 1978 ill ' ACKNOWLEDGMENT This study was conducted through the support of the Interagency Grizzly Bear Study Team. I wish to thank the IGBS for financial assistance, equipment, and aerial radio-tracking data; and IGBS seasonal field personnel for their attempts to trap bears in the study area and assistance in data collection. I wish to especially thank Mr. Joseph Basile, IGBS Team member, for his advice and encouragement during all phases of the study. The cooperation and patience of Paul H. Hoskins and personnel of the Hebgen Lake Ranger District, National Forest Service, is appreciated. I wish to express my appreciation to Dr. Harold Picton, the chairman of my committee, for his advice and assistance in preparation of the manuscript; and to Dr. Robert Moore and Dr. Robert L. Eng for reviewing the manuscript. Funding was provided by the National Park Service, the U. S. Forest Service, and the Montana Agricultural Experiment Station. TABLE OF CONTENTS Page VITA .............. ...................... ' . ii ACKNOWLEDGMENT .................................................. iii LIST OF TABLES ............ .. vi LIST OF FIGURES. ........................................ viii ABSTRACT .................................... ........... ix INTRODUCTION . ............ I THE STUDY A R E A ........ ................................. " . 3 Physiography. ..................................... 3 Land Use Practices.............. 6 Human - Grizzly Bear Encounters ....................... 7 METHODS. ...........•......... .. 8 Subunit Boundaries.............. 8 Grizzly Bear Distribution . ................ .. 8 Description of Vegetation ..... ............ .... 11 Recreational Use. .................... 12 RESULTS........ ................................... .....' 14 Grizzly Bear Distribution and Movements . 14 Yearly Variation......... 14 Seasonal Variation ................ 16 Elevational Variation. ...................... 17 ■ Exposures. ......... .. ............ ....•, 19 V Habitat Use and Food Habits .......................... 22 Habitat Use. .................................... 22 Use of Forested and Nonforested Habitats ...... 27 Food Habits and Scat Analysis. .................. 29 Distribution of Recreational Use...................... 35 Season of Use.......................... 35 Trail Use........................................ 35 Method of Travel .................. ....... 37 Length-of-stay .................................. 38 "Value" of Grizzlies to Recreationists .......... 39 Human - Grizzly Bear Encounters ..... ............ 40 DISCUSSION...................................... 42 Habitat Use and Seasonal Movements of Grizzly Bears . 42 Recreational Use. .................................... 46 Registration Rates................ ................... 48 LITERATURE C I T E D .................. ' .......... 50 APPENDIX 55 LIST OF TABLES Table Page 1. THE DISTRIBUTION OF GRIZZLY BEAR.SIGHTINGS, SCATS, ■ AND OTHER SIGN IN THE STUDY AREA SUBUNITS ......... 14 '■ 2. A YEARLY COMPARISON OF THE MONTHLY DISTRIBUTION OF . GRIZZLY BEAR SIGHTINGS, RADIO LOCATIONS, AND SIGN . 15 3. THE ELEVATIONS OF GRIZZLY BEAR SIGHTINGS AND RADIO LOCATIONS . ; . 19 4. THE ASPECTS (EXPOSURES) OF GRIZZLY BEAR SIGHTINGS, RADIO LOCATIONS, AND SIGN ............... 21 5. A COMPARISON OF HABITAT TYPE IMPORTANCE VALUES WITH AREA AVAILABILITY . ............ ........... 24 6. A YEARLY COMPARISON OF THE PERCENT OF GRIZZLY BEAR OBSERVATIONS IN FORESTED HABITATS ..... 29 ■ 7. THE CONTENTS OF GRIZZLY BEAR SCATS COLLECTED DURING 1975........ '........... .. ... 31 , 8 ., THE CONTENTS OF GRIZZLY BEAR SCATS COLLECTED DURING 1976. ..... , . ; . ........ 32. 9. THE DISTRIBUTION OF RECREATIONISTS BY T R A I L ........ ' 37 10. THE METHOD OF TRAVEL BY RECREATlONISTS. ... .38 ' 11. A SUMMARY OF RECORDED RECREATIONAL USE. ........ 38’ 12. THE "VALUE" OF GRIZZLY BEARS TO RECREATIONISTS BY PERCENT OF GROUPS . .......... .. .■ . i 39 13. A SUMMARY OF HABITAT■TYPES IN SUBUNITS.ONE, TWO, AND THREE . .. ; . 69 14. THE CONSTANCY AND- OCCURRENCE OF GRIZZLY BEAR FOOD ~ - ■ PLANTS AND THE IMPORTANCE VALUES OF HABITAT TYPES 'IN SUBUNITS ONE, TWO, AND THREE ' ■ 72 Vii ; , 15. A SUMMARY OF GRIZZLY BEAR SCAT CONTENTS FOR 1975 AND 1976 COMBINED ................ .. 73 16. A SEASONAL CLASSIFICATION OF GRIZZLY BEAR SCAT CONTENTS FOR 1975 AND 1976 COMBINED ............ .. 74 17. A SUMMARY OF THE NUMBER OF QUESTIONNAIRES MAILED . AND RETURNED........ .. .................... • • • 76 ' viii . LIST OF FIGURES . Figure Page I. The locations of study area boundaries, trails' and registration b o x e s ................ .. i , 4 ,2. Subunit divisions.within the study area. 9 3. The elevational variation of grizzly bear observa tions . ............................ 18 4. Percent of grizzly bear, locations in relation to .. the availability of nonforested and forested areas . in Subunits One, Two, and Three. .................... 28 5. A seasonal comparison of the distribution of grizzly bear observations and recorded, recreationist use in . the study area subunits. ............... 36 6. Cover letter, mailed with questionnaire . i ..... 58 7. Questionnaire mailed to registrants. ......... 59 8. The seasonal distribution of grizzly bear sightings. 61 9. The seasonal distribution of grizzly bear scats. 62 10. The seasonal distribution of other grizzly bear sign . 63 11. Radio locations and dens of Bear Four within the study area ............................. .64 12. Radio locations of Bear Four including the areas outside the study area ^ . 65 13. The distribution of black bear sightings and tracks. 6.7 14. The distribution of black bear and unidentified ■ grizzly bear scats ................................... 68 ix ABSTRACT The distribution of grizzly bears in relation to habitat areas and recreational use in the Cabin Creek - Hilgard Mountains region of southwestern Montana was investigated during 1975 and 1976. The distribution of grizzly bears was determined by ground and aerial sightings, radio tracking, and locations of other grizzly bear sign. The bears ^nd their sign were unevenly distributed over the study area with the most observations occurring in Cabin Creek Basin and the least in the Hilgard Mountains. Grizzly bear activity in the study area varied in intensity and distribution between 1975 and 1976. Locations of observations increased in elevation from May through September and were most frequent on south and southwest