Spatial Genetic Structure of Rocky Mountain Bighorn Sheep Ovis Canadensis Canadensis at the Northern Limit of Their Native Range

Canadian Journal of Zoology Spatial genetic structure of Rocky Mountain bighorn sheep Ovis canadensis canadensis at the northern limit of their native range Journal: Canadian Journal of Zoology Manuscript ID cjz-2019-0183.R2 Manuscript Type: Article Date Submitted by the 10-Dec-2019 Author: Complete List of Authors: Deakin, Samuel; University of Alberta, Department of Biological Sciences Gorrell, Jamieson; Vancouver Island University, Department of Biological Sciences Kneteman,Draft Jeffery; Government of Alberta, Alberta Environment and Parks Hik, David; University of Alberta, Department of Biological Sciences; Simon Fraser University, Department of Biological Sciences Jobin, Richard; Government of Alberta, Fish and Wildlife Enforcement Branch Coltman, D.; University of Alberta, Department of Biological Sciences Is your manuscript invited for consideration in a Special Not applicable (regular submission) Issue?: POPULATION GENETICS < Discipline, ALPINE < Habitat, TERRESTRIAL < Keyword: Habitat, UNGULATES < Taxon https://mc06.manuscriptcentral.com/cjz-pubs Page 1 of 56 Canadian Journal of Zoology 1 Spatial genetic structure of Rocky Mountain bighorn sheep Ovis canadensis 2 canadensis at the northern limit of their native range 3 4 Samuel Deakin, Department of Biological Sciences, University of Alberta 5 Jamieson C. Gorrell, Department of Biological Sciences, Vancouver Island University 6 Jeffery Kneteman, Alberta Environment and Parks, Government of Alberta 7 David S. Hik, Department of Biological Sciences, University of Alberta; and Department 8 of Biological Sciences, Simon Fraser University 9 Richard M. Jobin, Fish and Wildlife Enforcement Branch, Government of Alberta 10 David W. Coltman, Department of Biological Sciences, University of Alberta 11 Draft 12 13 14 15 16 17 18 19 20 21 22 23 1 https://mc06.manuscriptcentral.com/cjz-pubs Canadian Journal of Zoology Page 2 of 56 24 Abstract: 25 The Canadian Rocky Mountains are one of the few places on Earth where the spatial 26 genetic structure of wide-ranging species have been relatively unaffected by 27 anthropogenic disturbance. We characterised the spatial genetic structure of Rocky 28 Mountain bighorn sheep (Ovis canadensis canadensis (Shaw, 1804)) in the northern 29 portion of their range. Using microsatellites from 1495 individuals and mitochondrial DNA 30 sequences from 188 individuals, we examined both broad and fine scale spatial genetic 31 structure, assessed sex-biased gene flow within the northern portion of the species range, 32 and identified geographic patterns of genetic diversity. We found that broad-scale spatial 33 genetic structure was consistent with barriers to movement created by major river valleys. 34 The fine-scale spatial genetic structureDraft was characterized by a strong pattern of isolation- 35 by-distance, and analysis of neighborhood size using spatial autocorrelation indicated 36 gene flow frequently occurred over distances of up to 100 km. However, analysis of sex 37 specific spatial autocorrelation and analysis of mitochondrial haplotype distributions failed 38 to detect any evidence of sex-biased gene flow. Finally, our analyses reveal decreasing 39 genetic diversity with increasing latitude, consistent with patterns of post-glacial 40 recolonization of the Rocky Mountains. 41 42 Keywords: Spatial genetic structure, post-glacial recolonization, ungulates, terrestrial, 43 alpine, Rocky Mountain bighorn sheep, Ovis canadensis canadensis 44 45 46 2 https://mc06.manuscriptcentral.com/cjz-pubs Page 3 of 56 Canadian Journal of Zoology 47 Introduction 48 49 In the absence of anthropogenic habitat fragmentation, the natural population genetic 50 structure of species can be defined by natural geographic and ecological barriers (Slatkin 51 1985; 1987), or the dispersal capabilities of the species (Wright 1942; Kimura and Weiss 52 1964). When natural fragmentation is present, population spatial genetic structure 53 correlates with natural barriers to gene flow (Slatkin 1985; 1987). When a habitat lacks 54 natural barriers, spatial genetic structure may exhibit clinal differentiation if the population 55 range exceeds the maximal dispersal distance of the species (Kimura and Weiss 1964), 56 referred to as isolation-by-distance (Wright 1942). In the modern world anthropogenic 57 habitat fragmentation is common andDraft increasing, and the extent of pristine habitats where 58 natural phenomena can be studied is increasingly limited. 59 60 The Canadian Rocky Mountains are a vast, relatively undisturbed, mountainous habitat 61 which are part of an important international conservation initiative (Chester 2015). Areas 62 of high anthropogenic activity in the northern Rocky Mountains are avoided by certain 63 species (Proctor and Paetkau 2004; Rogala et al. 2011); however, these areas are minor 64 when considering the vastness of the region and the intensity of human activity in other 65 regions. Prior studies in this region identified broad-scale spatial genetic structure of 66 several species is correlated with natural landscape features which impede gene flow, 67 such as high elevation (Adams and Burg 2015) and major valleys (Serroya et al. 2012), 68 or subtle ecological factors such as landcover preference (Keyghobadi et al. 1999; 69 Gayathiri Samarasekera et al. 2012; Cullingham et al. 2016). Finer scale spatial genetic 3 https://mc06.manuscriptcentral.com/cjz-pubs Canadian Journal of Zoology Page 4 of 56 70 structure in the northern Rocky Mountains is primarily influenced by isolation-by-distance 71 (Forbes and Hogg 1999; Keyghobadi et al. 1999; 2005; Gayathiri Samarasekera et al. 72 2012; Weckworth et al. 2013; Cullingham et al. 2016). Therefore, this region offers a 73 range minimally affected by anthropogenic activities, where the natural spatial genetic 74 structure of a species can be observed. 75 76 Following the Wisconsin glaciation, many species of flora and fauna recolonized 77 northwestern North American including the Rocky Mountains. The two main refugial 78 sources for this post-glacial recolonization were the Beringian refugium in northeastern 79 Siberia and northwestern North America, and the Southern refugium, comprised by most 80 of the modern-day mainland UnitedDraft States (Hewitt 2004; Shafer et al. 2010). Genetic 81 signatures of recolonization, primarily resulting from the founder effect (Frankham 1997), 82 are well documented for many contemporary populations of flora (Mitton et al. 2000; 83 Jørgensen et al. 2002; Anderson et al. 2006; Godbout et al. 2008) and fauna (Stone and 84 Cook 2000; Flagstad and Røed 2003; McDevitt et al. 2009;Latch et al. 2009). By 85 examining patterns of genetic diversity across the landscape, we can make inference 86 about a species recolonization patterns in the northern Rocky Mountains (Shafer et al. 87 2010). 88 89 The range of Rocky Mountain bighorn sheep (Ovis canadensis canadenis (Shaw, 1804)) 90 extends along the Rocky Mountains from Arizona to Alberta and British Columbia, to 91 approximately 55o N. For the southern portion of the species range, studies into the 92 movement (DeCesare and Pletscher 2006) and genetic structure (Miller et al. 2012; 4 https://mc06.manuscriptcentral.com/cjz-pubs Page 5 of 56 Canadian Journal of Zoology 93 Driscoll et al. 2015) of sheep populations are numerous. In the northern portion of their 94 range studies of movement patterns (Festa-Bianchet 1986a; Poole et al. 2016) and 95 population genetic structure (Luikart and Allendorf 1996; Forbes and Hogg 1999) are 96 more limited. Unlike the southern areas, the northern ranges are relatively unfragmented, 97 unimpacted by translocations, and unaffected by population declines or disease-related 98 die-offs. Notably, respiratory disease has never been reported north of the Bow River 99 (Fig. 1) (Government of Alberta 2015). Thus, the northern Rocky Mountains are well 100 suited to study the natural spatial genetic structure of Rocky Mountain bighorn sheep in 101 a relatively intact landscape. Additionally, bighorn sheep in the northern Rocky Mountains 102 are at the northern limit of the species range, and therefore should show signatures of the 103 range edge effect and recent post-glacialDraft recolonization. 104 105 Broad-scale spatial genetic structure of Rocky Mountain bighorn sheep is likely influenced 106 by natural landscape features. Studies of desert bighorn sheep (Ovis canadensis nelsoni 107 (Merriam, 1897)) indicate most fenced highways are barriers to gene flow (Epps et al. 108 2005; 2018). However, most of highways in the northern Rocky Mountains lack fences. 109 Instead, it is likely that natural features of the heterogenous landscape are barriers to the 110 gene flow of these alpine ungulates. Alpine ungulates prefer to occupy high elevations; 111 thus, their movement and distribution are primarily restricted by the availability of this 112 habitat. Due to this habitat preference, the population genetic structure of thinhorn sheep 113 (Ovis dalli (Nelson, 1884)) and mountain goats (Oreamnos americanus (Blainville, 1816)) 114 have been found to correlate with areas of high elevation (Worley et al. 2004; Shafer et 115 al. 2011; Sim et al. 2018). Similarly, Rocky Mountain bighorn sheep show preferences for 5 https://mc06.manuscriptcentral.com/cjz-pubs Canadian Journal of Zoology Page 6 of 56 116 higher elevation alpine meadows (Fiesta-Bianchet 1988; Loehr 2006), situated close to 117 steep cliffs which can be used to escape predators (Fiesta-Bianchet 1988; Loehr 2006). 118 Therefore, we expect broad-scale

Load more