View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by ScholarWorks@UA CHARACTERIZATION OF MUSKOX HABITAT IN NORTHEASTERN ALASKA A THESIS Presented to the University of Alaska in Partial Fulfillment of the Requirements for the Degree of MASTER OF SCIENCE By Constance Marsha O'Brien, B.A. Fairbanks, Alaska December 1988 CHARACTERIZATION OF MUSKOX HABITAT IN NORTHEASTERN ALASKA by Constance Marsha O'Brien RECOMMENDED: r—Ex Officifl Committee Member Advisory Committee Chair Head, Department of Biology, Fisheries and Wildlife APPROVED: Dean. College of Natiixal Sciences Dean of the Graduate School Date ' ABSTRACT In northeastern Alaska, muskoxen have been most often found in riparian habitats and proximate uplands. Vegetation was studied in nine adjacent river drainages; six of the drainages are regularly used by muskoxen. Twenty-two vegetation/land cover types were described using aerial photographs, point-intercept sampling, and ocular cover estimates. The proportion of each cover type was estimated for each drainage and compared among drainages by MANOVA. There was no significant difference among non-muskox drainages in the average proportion of cover types. A marginally significant difference was found among muskox drainages. There were no significant differences in the proportions of each vegetation type in non-muskox drainages versus muskox drainages. Five vegetation types associated with high forage quality and availability and low snow accumulation were often used by muskoxen. Four of these five vegetation types typically had <7% cover in the nine drainages and are critical habitat components in northeastern Alaska. i i i TABLE OF CONTENTS LIST OF F I G U R E S ............................................. .. vi LIST OF TABLES.............................................................vii LIST OF APPENDICES vi i i ACKNOWLEDGMENTS ......................................................... ix INTRODUCTION...................................... 1 STUDY OBJECTIVES......................................................... 5 STUDY AREA DESCRIPTIONS AND MUSKOX DISTRIBUTION .................... 6 N i g u a n a k .............................................................. 12 O k e r o k o v i k ........................................................... 13 J a g o .................................................................. 14 Okpilak................................................................ 15 H u l a h u l a ..............................................................15 Sadi erochit........................................................... 16 K a t a k t u r u k ........................................................... 17 T a m a y a r i a k ........................................................... 18 West Tamayariak....................................................... 19 METHODS .................................................................... 21 Selection of Areas for Habitat Description .................... 21 Reconnaissance of Study Areas...................................... 22 Quantitative Vegetation Description............................... 23 Vegetation Sampling ......................................... 23 Twinspan......................................................... 25 Stereoscopic Photograph Interpretation ......................... 26 Ground-Truthing.. 28 Statistical Comparisons of Study Areas ......................... 29 Fecal A n a l y s i s ....................................................... 31 RESULTS .................................................................... 33 Reconnaissance of Study Areas...................................... 33 Quantitative Vegetation Description................................39 Vegetation Sampling ......................................... 39 Twinspan......................................................... 43 Stereoscopic Photograph Interpretation ......................... 44 Ground-Truthing....................................................... 52 i v TABLE OF CONTENTS, continued RESULTS, continued Statistical Comparisons of Study Areas ......................... 54 Fecal A n a l y s i s ....................................................... 56 DISCUSSION.................................................................. 60 Muskox Diet........................................................... 60 Vegetation Types .....................................................63 Muskox Use of Study Areas........................................... 67 CONCLUSIONS AND RECOMMENDATIONS ....................................... 70 REFERENCES CITED........................................................... 73 PERSONAL COMMUNICATIONS ................................................ 83 v LIST OF FIGURES Figure 1. Rivers of the coastal plain in northeastern Alaska. 7 Fiqure 2. Study areas along the Jago, Okerokovik, and Niguanak rivers....................................................... 8 Figure 3. Study areas along the Sadlerochit, Hulahula, and Okpilak rivers............................................. 9 Figure 4. Study areas along the West Tamayariak, Tamayariak, and Katakturuk rivers .................................... 10 Figure 5. Estimated cover of 22 vegetation/land cover types in nine study areas in the A N W R ......................... 46 Figure 6. Number of ground-truthed sites (45 total) in eight accuracy categories before and after four descriptors were omitted for photo-interpretations.................. 53 vi LIST OF TABLES Table 1. Descriptions of vegetation/land cover types .............. 34 Table 2. Alpha-numerical codes and names of vegetation/land cover types .....................................................47 Table 3. Cross-reference of vegetation/land cover types in which muskoxen were observed in four ANWR studies .... 48 Table 4. Estimated cover (%) of frequently used upland and riparian vegetation types in nine study areas in the ANWR......................................................... 50 Table 5. Estimated cover (%) of infrequently used vegetation types in nine study areas in the A N W R ....................... 51 Table 6. Univariate F-test results for variables (vegetation/ land cover types) analyzed in two MANOVAs ................ 55 Table 7. Relative percent densities of plant fragments in winter and winter-type samples of muskox feces from four study areas in Alaska. .'................................ 57 Table 8. Relative percent densities of plant fragments in summer samples of muskox feces from four study areas in Alaska ................................................ 58 Table 9. Plants showing evidence of grazing and browsing by muskoxen during reconnaissance of study areas ........... 59 vii LIST OF APPENDICES Appendix A. Options used in Twinspan analysis of transects .... 84 Appendix B. Percent cover of plant species along 170 point-intercept transects in 15 vegetation types . 85 Appendix C. Percent cover of major taxa and cover categories for 177 ocular estimates (releves) made in conjunction with point-intercept transects to ' describe 16 vegetation types ........................... 105 Appendix D. Twinspan grouping of transects .......................... 109 Appendix E. Estimated cover of vegetation/land cover types for nine drainages in the ANWR, in hectares (ha) and percent (%)............................................. 113 Appendix F. Alpha-numerical codes and names of vegetation/ land cover types .......................................... 114 vi i i ACKNOWLEDGMENTS This study was funded by the Alaska Department of Fish and Game through the Alaska Cooperative Wildlife Research Unit. The U.S. Fish and Wildlife Service, Arctic National Wildlife Refuge, provided logistic support, information, and aerial photographs. Special thanks are extended to the members of my committee: Dr. David Klein, chairman; Patricia Reynolds; and Drs. Robert White, Terry Chapin, and Gerald Garner. Their continued interest in the project and scrutiny of the manuscript were greatly appreciated. Dr. Dana Thomas provided crucial assistance in disentangling the statistics. I would like to thank Drs. Skip Walker, Tass Kelso, and David Murray for contributing their time and expertise. Norma Mosso, Kathy Pearse, and Nan Lederer each contributed enormously to this project. I would like to thank the many University of Alaska professors and graduate students who assisted me, particularly Robin O'Connor, Kathleen Frisby, Claire Fleischman, Cris Linesch, and Clay Cranor for being there when I needed them most. Drs. John Marr, Charles Olmsted, and David Cooper introduced me to the dynamics of arctic and alpine ecosystems, and I thank them. Special recognition goes to my husband, Cort Zachel, and to my parents for their continued support during this process. ix INTRODUCTION In 1930, muskoxen (Ovibos moschatus) from Greenland were transplanted to Alaska where they were held in captivity in College, Alaska. In 1935 and 1936, 31 of these muskoxen were released on Nunivak Island, Alaska. Subsequently, there were two transplants of muskoxen from Nunivak Island to the northeastern coast of Alaska, in an effort to reestablish muskoxen in historical range areas (Burris and McKnight 1973). Fifty-one muskoxen were released during the first transplant in 1969 on Barter Island (Griffin 1969, in U.S. Fish and Wildlife Service (USFWS) 1986), and in 1970, an additional 13 muskoxen were released at the Kavik River, 130 km west of Barter Island (Jennings and Burris 1971, in USFWS 1986). Muskoxen were also transplanted from Nunivak