Wildlife use of fire-disturbed areas in sagebrush steppe on the Idaho National Engineering Laboratory by William Edward Moritz 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 William Edward Moritz (1988) Abstract: From June, 1984 through June, 1987, a study was conducted on the Idaho National Engineering Laboratory (INEL) in southeast Idaho to collect data on sage grouse (Centrocercus urophasianus), pronghorn (Antilocapra americana) and small mammal use of nine burned areas (fire s cars) of various ages in sagebrush steppe- Information on plant community composition of burned areas and adjacent nonburned (control) areas was reported. Fire scars were characterized by an absence of sagebrush, although revegetation was not clearly directional or predictable. Two years of seasonal use by sage grouse and pronghorn of fire scars and control areas were determined. Sage grouse use of a newly burned area was significantly greater (p<0.05) than controls. Fire scars dominated by cheatgras s (Bromus textorurn) were used by sage grouse significantly less than controls. Incomplete burns created a mosiac pattern of vegetation which sage grouse used significantly more than adjacent controls. Significant trends in use by sage grouse of older burned areas, dominated by perennial grasses/rabbitbrush (Chrysothamnus viscidiflorus) were not detected. The lush growth of grasses and forbs following disturbance attracted pronghorn, as use of the fire scar was significantly higher than controls. Pronghorn use of cheatgrass-dominated fire scars was significantly greater than controls. Overall use of incompletely-burned areas was not significantly different than controls, although seasonal- differences existed. Results of pronghorn use of perennial grass/rabbitbrush fire scars,indicated that fire did not reduce use of areas, although use of fire scars was not significantly greater in all areas. Mule deer (Odocoileus hemionus) and elk (Cervus elaphus) use of burned areas appeared greater than controls. Small mammal populations on fire scars were similar in composition but of lesser density than adjacent populations in sagebrush. WILDLIFE USE 0,F FIRE-DISTURfiED AREAS IN SAGEBRUSH STEPPE ON THE IDAHO NATIONAL ENGINEERING LABORATORY by William Edward Moritz A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Fish and Wildlife Management MONTANA STATE UNIVERSITY Bozeman, Montana February 1988 ZyIcx", n V S l Z M ? Ji LS I i APPROVAL of a thesis submitted by William Edward Moritz This thesis has been read by each member of the thesis committee and has been found to be satisfactory regarding content, English usage, format, citations, bibliographic style, and consistency, and is ready for Tfu. 12. n?t Date Approved for the Mg/j'oh: Department Date Z Head, Major Department Approved for the College of Graduate Studies Date Graduate Dean A ill STATEMENT OF PERMISSION TO USE In presenting this thesis in partial fulfillment of the requirements for a master's degree at Montana State University, I agree that the Library shall make it available to borrowers under the rules of the Library. Brief quotations from this thesis are allowable without special permission, provided that accurate acknowledgment of source is made. Permission for extensive quotation from or reproduction of this thesis may be granted by my major professor, or in his absence, by the Dean of Libraries when, in the opinion of either, the proposed use of the material is for scholarly purposes. Any copying or use of the material in this thesis for financial gain shall not be allowed without my written permission. LjJ iv ACKNOWLEDGMENTS This research was funded by the Office of Health and Environmental Research, United States Department of Energy. I wish to thank the following individuals for their advice and assistance: 0. D. Markham, T . D . Reynolds, and S. J . Rope of the Department of Energy; J . E . Anderson and B. L . Keller of Idaho State University; M . P. Stafford of the University of Idaho; and J . E . Toepfer of Montana State University. Field assistance was provided by students from the Associated Western Universities summer program. Special appreciation is due my major professor, Dr. R. L . Eng, for his support and friendship. I also thank my committee members, Drs. R . J . Mackie, B. S. Sindelar, W. S. Gould, and J . T . Taylor for their advice and critical reviews of this thesis. Words cannot express the love and understanding of my wife, Zoe, throughout this project; to her I owe the greatest thanks. V TABLE OF CONTENTS Page APPROVAL................................................ ii STATEMENT OF PERMISSION TO USE........................ iii ACKNOWLEDGMENTS........................................ iv TABLE OF CONTENTS...................................... v LIST OF TABLES......................................... vii LIST OF FIGURES.............. xi ABSTRACT........... xiii INTRODUCTION........................................... I STUDY AREA.......................‘___ :................. 4 METHODS............................. 7 Introduction........................................ 7 Vegetation Measurements and Analysis......... 9 Measurement of Sage Grouse and Pronghorn Use..... 11 Measurement of Small Mammal Use................... 13 Measurement of Population Indices.............. 14 RESULTS AND DISCUSSION................................ 17 Vegetation.......................................... 17 7 MIRD Study Area (Area # I )............. ........ 17 INEL Study Area (Area #2)....................... 21 Rabbit Ears Study Area (Area #3)............... 23 Utah P&L Study Area (Area #4).................. 25 Fire Station Study Area (Area //5)............ 27 Arco Highway Study Area (Area #6)............. 29 N Idaho 22 Study Area (Area #7)............... 30 B&B Co Study Area (Area #8).................... 32 Trac Flat Study Area (Area #9).......... 34 Discussion of Post-burn Vegetation Trends.... 36 v i TABLE OF CONTENTS— Continued Page Sage Grouse........................................ 46 Immediate Response Following a Complete Burn.. 46 Use of an Incompletely-burned Fire Scar...... 52 Use of Perennial Grass/Rabbi thrush Fire Scars. 56 Pronghorn.......................................... 60 Immediate Response Following a Complete Burn.. 60 Use of an Incompletely-burned Fire Scar........ 64 Use of Perennial Grass/Rabbi thrush Fire Scars. 66 Elk................................................. 6 9 Small Mammals.......... ........................... 70 Use of Cheatgrass-dpminated Fire Scars.......... 71 Use of an Incompletely-burned Fire Scar...... 75 Use of Perennial Grass/Rabbit brush Fire Scars. 76 Trends in Small Mammal Use............. ........... , 7g SUMMARY................................................. 8 2 LITERATURE CITED...,.............. •............ ..... f . 8'6 APPENDICES.............................................. 96 Appendix I -Study Area Maps........... ............... 9 7 • Appendix, 2-Sage Grouse Raw Data Sets............... 106 Appendix 3-Pronghorn Raw Data Sets.................. 116 Appendix 4-Small Mammal Raw Data Sets 126 vii ■LIST OF TABLES Table ' ■" Page 1. Study area fire history......................... 5 2. Average canopy height, (cm) of Artemisia tridentata on burn and control sample lines on all study areas, 1986 (number of plants measured in parentheses).................... % g 3. Relative amounts of dead and living Artemisia plants occurring in transects on control areas , 1986............... ................... 20 . I ■ 4. Sage grouse fecal pellet densities (single pellets/ha) found in all sample periods on all study areas , 1985-1987............... 4 g 5. Frequency of single sage grouse pellets (plots/grid) occurring on pellet plots in all sample periods on all sample areas, 1985-1987 (all data arcsine transformed before analysis)..,....!...... .............. 51 6. Sage grouse roost pelle,t groups occurring on pellet plots in all; sample periods on all study areas , 1985-1987 ...................... 5 4 7. Pronghorn fecal pellet -’densities (groups/ha) occurring on pellet plots in all s-ample periods on all study areas , , 1985-1987 ...... 62 8 . Pronghorn fecal pellet group frequency (plots/grid) found in all sample periods on all study areas, 1985-1987 (all data arcsine transformed before analysis).... 65 9. Small mammal population indices. Fall, 1985.... 73 10. Small mammal population indices, Spring, 1986.. 74 vii i LIST OF TABLES— Continued Table Page 11. Sage grouse pellet densities (pellets/ha) and % joccurrence on the turn and control pellet grids, 7MIRD study area, 1985-1987... 107 12. Sage grouse pellet densities (pellets/ha) and % occurrence on the burn and control grids, INEL study area, 1985-1987............. 108 13. Sage grouse pellet densities (pellets/ha) and % occurrence on the burn and control grids. Rabbit Ears study area, 1985-1987............. 109 14. Sage grouse pellet densities (pellets/ha) and % occurrence on the burn and control grids, Utah P&L. study area, 1985-1987 .............. H O 15. Sage grouse pellet densities (pellets/ha) and % occurrence on the burn and control grids. Fire Station study area, 1985-1987.......... Ill 16. Sage grouse pellet densities (pellets/ha) and % occurrence on the burn and control grids, Arco Hwy study area, 19 8 5-1987 .............. 1 1 2 17. Sage grouse pellet densities (pellets/ha) and % occurrence on the burn and control grids,