Distribution and Biogeography of the Alaskan Hare (Lepus Othus)
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Distribution and biogeography of the Alaskan hare (Lepus othus) Item Type Thesis Authors Cason, Michelle M. Download date 23/09/2021 10:11:01 Link to Item http://hdl.handle.net/11122/6604 DISTRIBUTION AND BIOGEOGRAPHY OF THE ALASKAN HARE (LEPUS OTHUS) By Michelle M. Cason RECOMMENDED: Dr. Derek Sikes Advisory Committee Member Dr. Kris Hundertmark Advisory Committee Member Dr. Link Olson Advisory Committee Chair Dr. Diane Wagner Chair, Department of Biology and Wildlife APPROVED: Dr. Paul Layer of DISTRIBUTION AND BIOGEOGRAPHY OF THE ALASKAN HARE (LEPUS OTHUS) A THESIS Presented to the Faculty of the University of Alaska Fairbanks in Partial Fulfillment of the Requirements for the Degree of MASTER OF SCIENCE By Michelle M. Cason, B.S. Fairbanks, Alaska May 2016 ABSTRACT The Alaskan Hare (Lepus othus Merriam 1900) is the largest lagomorph in North America but remains one of the most poorly studied terrestrial mammals on the continent. Its current distribution is restricted to western Alaska south of the Brooks Range, but historical anecdotal accounts of occurrences north of the Brooks Range (the North Slope) have led to confusion over its past, present, and predicted distribution. To clarify the historical range of L. othus, we surveyed North American museum collections and georeferenced voucher specimens (Supplemental File Appendix 1.1). We also located a specimen from the North Slope of Alaska long presumed lost and whose identity had come to be questioned. The rediscovery of this missing specimen suggests the occurrence of at least one Alaskan Hare on the North Slope as recently as the late 1800s. Because unforested ecosystems such as tundra and Arctic grasslands have decreased in Alaska since the last glacial maximum, and L. othus occurs in unforested habitat, we expected to observe low genetic diversity in the mitochondrial control region of L. othus. However, with recently collected specimens from regions in Alaska that were poorly represented in the past (i.e. Alaska Peninsula, Little Diomede, and Kotzebue Sound), we discovered more genetic diversity and population structure than was found in previous studies, including similar haplotypes from the Alaska Peninsula and from eastern Russia. This suggests there may have been 2 distinct colonization events of northern hares in Alaska, or introgression from L. timidus and a mitochondrial sweep that has been restricted to the Alaska Peninsula and Bristol Bay area. Our morphological analyses of the difference between the two subspecies, L. o. othus and L. o. poadromus, were ambiguous, with principal components analysis and simple linear regression v indicating the presence of a latitudinal size cline and discriminant function analysis revealing successful group assignment that is not solely based on latitude. Our research clarifies the current and recent distribution of the Alaskan Hare and reveals more genetic diversity than previously suspected in the mitochondrial control region. We also observed a new biogeographic pattern and closer mtDNA association with L. timidus, which, combined with new island specimens and observations, suggests gene flow across the Bering Strait. It also highlights the importance of maximizing sample sizes and sampling widely across a taxon’s geographic distribution. vi TABLE OF CONTENTS Page Signature Page ........................................................................................................................................i Title Page ..............................................................................................................................................iii Abstract ................................................................................................................................................. v Table of Contents ................................................................................................................................ vii List of Figures .......................................................................................................................................ix List of Tables .........................................................................................................................................x Acknowledgements.............................................................................................................................. xi Dedication page.................................................................................................................................. xii Introduction ........................................................................................................................................... 1 Chapter 1:............................................................................................................................................... 9 Abstract ............................................................................................................................................. 9 Introduction ..................................................................................................................................... 10 Materials and Methods .................................................................................................................... 13 Results ...............................................................................................................................................15 Discussion ........................................................................................................................................ 19 Literature Cited................................................................................................................................27 Tables............................................................................................................................................... 35 Figures ............................................................................................................................................. 38 Chapter 2: ............................................................................................................................................. 43 Abstract............................................................................................................................................ 43 Introduction ..................................................................................................................................... 44 vii Materials and Methods 49 Results .............................................................................................................................................. 53 Discussion ........................................................................................................................................ 57 Literature Cited .............................................................................................................................. 63 Tables............................................................................................................................................... 71 Figures ............................................................................................................................................. 74 Conclusion ........................................................................................................................................... 83 Litureature Cited ..................................................................................................................................85 viii LIST OF FIGURES Page Figure 1.1—Previously published distribution maps for Lepus othus.......................................... 388 Figure 1.2—IUCN range maps of Lepus othus, L. arcticus, and L. americanus............................39 Figure 1.3—Updated distrubution map of Lepus othus....................................................................40 Figure 1.4.— Spatial distribution model of the present distribution of Lepus othus...................... 41 Figure 2.1.— Lepus othus distribution ................................................................................................74 Figure 2.2.—Populations and specimen collection localities used in molecular analyses ............ 75 Figure 2.3.—Collection localities of specimens used in morphometric analyses ......................... 76 Figure 2.4a.—Median-joining network .............................................................................................77 Figure 2.4b.—Median-joining network with haplogroups and species indicated ......................... 78 Figure 2.4c.—Close-up of median-joining network .........................................................................79 Figure 2.5.—Bayesian skyline plot ofLepus othus..........................................................................80 Figure 2.6.—Plot from principal components analysis....................................................................81 Figure 2.7.— Series of discriminant function analysis canonical plots ........................................... 82 ix LIST OF TABLES Page Table 1.1.—Names and abbreviations of museums and other collections searched ...................... 35 Table 1.2.—Environmental variables and their importance to the spatial distribution model ..... 37 Table 2.1.—Analysis of Molecular Variance (AMOVA) for Lepus othus populations................71 Table 2.2.—Population comparisons of Lepus othus.......................................................................71 Table