Spatial population genetics reveals competitive imbalances threatening local apex predator persistence

Abstract

The eastern wolf (Canis lycaon), a species of conservation concern in Canada, is currently restricted to small fragmented populations in south-central Ontario and hybridizes with both encroaching gray wolves and coyote-like canids. We examined niche dynamics in canids undergoing hybridization to determine whether competition among individuals with coyote (Canis latrans) or gray wolf (Canis lupus) ancestry, or their related hybrids, could threaten persistence of the eastern wolf in south-central Canada. Our integrative approach combined extensive genotyping and comparative niche analyses across the hybrid zone to assess available and utilized niche space across all three parental species and their hybrids within the zone of admixture. We focused on detecting niche imbalances within the canid clade that indicate competitive threats, and used these data to identify specific geographic regions that disproportionately favor eastern wolves and might confer natural exclusion of competing canids. We detected low genetic and ecological differentiation among groups across the region. Niche dynamics in the admixture zone were dominated by gray wolf and coyote-like canids, with coyote-like canids in particular exhibiting niche space that overlapped entirely with eastern wolves. Conservation action for eastern wolves must either exploit the narrow niche space that differentiates them from other canids, representing ~5% of their currently occupied space, or accept whichever group dominates the landscapes regardless of genetic makeup. This study suggests that competitive disadvantage can limit species' recovery efforts, and thereby potentially warrant management that targets factors promoting ecological differentiation between groups.