INFLUENCE OF PRESCRIBED FIRE ON STONE'S SHEEP AND ROCKY MOUNTAIN ELK: FORAGE CHARACTERISTICS AND RESOURCE SEPARATION by Krista L. Sittler B.Sc. University of Victoria, 2008 THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE IN NATURAL RESOURCES AND ENVIRONMENTAL STUDIES (BIOLOGY) UNIVERSITY OF NORTHERN BRITISH COLUMBIA September 2013 © Krista L. Sittler, 2013 UMI Number: 1525688 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. UMI Dissertation PiiblishMiQ UMI 1525688 Published by ProQuest LLC 2014. Copyright in the Dissertation held by the Author. Microform Edition © ProQuest LLC. All rights reserved. This work is protected against unauthorized copying under Title 17, United States Code. ProQuest LLC 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, Ml 48106-1346 Abstract For over 30 years prescribed fire has been used as a management tool to enhance ungulate habitat in northeastern British Columbia (BC), where up to 7,800 ha are burned annually. Yet relatively few studies have quantified the role of fire on both plant and animal response, and whether it enables competition between focal grazing species such as Stone's sheep (Ovis dalli stonei) and elk (Cervus elaphus). Seven prescribed bums (150-1,000 ha) were implemented in the spring of 2010 and 2011 in the Besa-Prophet area of northern BC. I examined the response of Stone's sheep and elk to seasonal changes in forage quantity and quality by elevation in treatment versus control areas. I monitored vegetation and fecal pellet transects at a fine scale and used Landsat imageiy, survey flights and GPS telemetry at a landscape scale. By one year after burning, forage digestibility and rates of forage growth were higher on burned than unbumed areas. At both scales Stone's sheep and elk always used bums more than control areas in winter. Stone's sheep and elk appeared to partition their use of the landscape through topography and land cover. Increased use of burned areas suggests that prescribed fire enhanced habitat value for grazing ungulates in the short-term. By altering animal distributions, however, the use of prescribed fire has the potential to change complex predator-prey interactions in northern BC. Table of Contents Abstract .................................................................................................................................................... ii Table of Contents ................................................................................................................................... iii List of Tables ............................................................................................................................................v List of Figures ...................................................................................................................................... xiii Acknowledgements .............................................................................................................................xvii Chapter 1. Introduction ........................................................................................................................... 1 Background .......................................................................................................................................... 1 Prescribed burning in the Peace Region of northern British Columbia ......................................1 Vegetation response to fire and forage for ungulates ...................................................................4 Stone's sheep and elk .......................................................................................................................5 Resource partitioning and the potential for competitive interactions ........................................ 7 Objectives .............................................................................................................................................7 Organization of the thesis ..................................................................................................................10 Chapter 2. Response of vegetation to prescribed fire in the northern Rockies: Implications for Stone's sheep and elk .................................................................................................11 Abstract .............................................................................................................................................. 11 Introduction ........................................................................................................................................13 Study area ........................................................................................................................................... 16 Methods ..............................................................................................................................................20 Prescribed bums ............................................................................................................................20 Nutritional quality .........................................................................................................................24 Bum severity and landscape-level vegetation response to fire ................................................ 24 Animal response to prescribed bums ..........................................................................................26 Statistical analysis .............................................................................................................................26 Bum severity .................................................................................................................................27 Vegetation quantity and quality .................................................................................................. 27 Rate of forage growth ................................................................................................................... 28 Vegetation composition ................................................................................................................ 28 Vegetation height ..........................................................................................................................28 Winter vegetation in pre-bum versus post-bum areas .............................................................. 28 Pellet counts ..................................................................................................................................29 Distribution flights ....................................................................................................................... 29 Grazing ...........................................................................................................................................30 Results................................................................................................................................................30 Prescribed fires and bum severity ............................................................................................... 30 Vegetation quantity ...................................................................................................................... 30 Forage quality ................................................................................................................................38 Animal use of bums-pellet counts ..............................................................................................43 Animal use of bums-distribution flights .................................................................................... 44 Range exclosures and forage quantity .........................................................................................45 Discussion ......................................................................................................................................... 45 Prescribed burning ........................................................................................................................ 45 Response of vegetation to fire ..................................................................................................... 51 iii Use of bums by ungulates ............................................................................................................ 54 Management Implications.................................................................................................................58 Chapter 3. Resource separation on a landscape of prescribed bums: Stone's sheep and elk in the northern Rockies ....................................................................................................................60 Abstract .............................................................................................................................................. 60 Introduction ........................................................................................................................................62 Study area ........................................................................................................................................... 63 Methods .............................................................................................................................................