Spatial genetic and morphologic structure of wolves and coyotes in relation to environmental heterogeneity in a Canis hybrid zone

Abstract

Eastern wolves have hybridized extensively with coyotes and gray wolves and are listed as a 'species of special concern' in Canada. However, a distinct population of eastern wolves has been identified in Algonquin Provincial Park (APP) in Ontario. Previous studies of the diverse Canis hybrid zone adjacent to APP have not linked genetic analysis with field data to investigate genotype-specific morphology or determine how resident animals of different ancestry are distributed across the landscape in relation to heterogeneous environmental conditions. Accordingly, we studied resident wolves and coyotes in and adjacent to APP to identify distinct Canis types, clarify the extent of the APP eastern wolf population beyond the park boundaries and investigate fine-scale spatial genetic structure and landscape-genotype associations in the hybrid zone. We documented three genetically distinct Canis types within the APP region that also differed morphologically, corresponding to putative gray wolves, eastern wolves and coyotes. We also documented a substantial number of hybrid individuals (36%) that were admixed between 2 or 3 of the Canis types. Breeding eastern wolves were less common outside of APP, but occurred in some unprotected areas where they were sympatric with a diverse combination of coyotes, gray wolves and hybrids. We found significant spatial genetic structure and identified a steep cline extending west from APP where the dominant genotype shifted abruptly from eastern wolves to coyotes and hybrids. The genotypic pattern to the south and northwest was a more complex mosaic of alternating genotypes. We modelled genetic ancestry in response to prey availability and human disturbance and found that individuals with greater wolf ancestry occupied areas of higher moose density and fewer roads. Our results clarify the structure of the Canis hybrid zone adjacent to APP and provide unique insight into environmental conditions influencing hybridization dynamics between wolves and coyotes.

Taxonomic Implications of Morphological and Genetic Differences in Northeastern Coyotes (Coywolves) (<em>Canis latrans</em> × <em>C. lycaon</em>), Western Coyotes (<em>C. latrans</em>), and Eastern Wolves (<em>C. lycaon</em> or <em>C. lupus lycaon</em>)

“…These results are further supported by large effect sizes (Table 1); also see Rutledge et al (2010b) and Benson et al (2012) for Eastern Wolf-Coyote body size comparisons. Furthermore, western Coyotes close to the range of the northeastern Coyote (i.e., in the Midwest or the Great Lakes area) are no bigger than Coyotes found elsewhere (Figure 1) (appendix 1).…”

“…Conversely, a similar argument could be made that northeastern Coyotes are a southern extension of hybridized Eastern Wolf populations (Wilson et al 2009, Benson et al 2012. I suggest that northeastern Coyotes should most appropriately be called "Coywolves," Canis latrans × C. lycaon, as this terminology most succinctly describes their mixed heritage and current unique genetic (Kays et al 2010;Way et al 2010;vonholdt et al 2011, page 5 and Figure S5) and morphological characteristics (this study ;Way 2007a).…”

“…albert et al (2006) similarly noted that natural selection may influence the relative fitness of hybrids in terms of differential survival and may therefore modulate the observed proportion of hybrids. Given that Eastern Wolves are functionally extinct in most of northeastern North america (Benson et al 2012;Wheeldon and Patterson 2012) and northeastern Coyotes colonized the region five times faster than western Coyotes coming from south of the Great Lakes through the ohio area (Kays et al 2010), the elevated survival and fitness levels of northeastern Coyotes in anthropogenically altered northeastern North america suggest that this canid is better adapted to this region-at least in areas south of the Moosedominated "North Woods" of northern New England. Thus, it appears that hybridization in this case positively benefited two closely related species, whereby Eastern Wolf genes now persist in an area where the animal has been extirpated, and western Coyote genes have spread to an area where they previously did not exist (Kays et al 2010).…”

“…From a conservation/recovery perspective, initiatives involving the re-introduction of Eastern/Red Wolves (i.e., Type 3 Wolf) or Gray Wolf × Eastern Wolf hybrids (Type 4) ( Table 2) into the region will be affected by their relationship with northeastern Coyotes (Wilson et al 2009). any Eastern Wolves colonizing northeastern North america may already be assumed to be large "Coyotes" by state wildlife agencies because of their morphological and genetic similarities to northeastern Coyotes (Benson et al 2012).…”

“…Wheeldon and Patterson (2012) differentiated hybridized wolves and coyotes in northeastern ontario through genetic and morphological analysis but did not directly correlate the two variables. Similarly, Benson et al (2012) characterized spatial genetic and morphologic structure of wolves and coyotes around algonquin Park in ontario and compared mass to Canis type but did not explicitly correlate mass to DNa haplotypes within a given Canis type.…”