Genetic legacy and ecological differences of grey wolves (Canis lupus) in southern British Columbia

Grey wolves (Canis lupus) historically occupied much of southern British Columbia, including west coast temperate rainforest ecosystems. However, widespread predator control programs and habitat changes during the late nineteenth and early twentieth centuries resulted in significant population declines and local extirpations across portions of the region.¹ ²

Today, wolves are experiencing a significant recovery in southern British Columbia, with a marked westward expansion toward the Pacific coast. This process represents a complex interaction between genetic legacies and ecological specializations, reflecting the influence of historical population reductions, anthropogenic pressures, and the environmental divergence between coastal and inland habitats.

Genetic legacy of re-establishing wolves

Genetic analyses indicate that re-establishing wolves in southern British Columbia are predominantly derived from interior continental populations historically associated with the Canadian Rockies, with a comparatively modest contribution from coastal lineages.³ ⁴ Wolves inhabiting the Great Bear Rainforest and the surrounding island archipelagos display distinct genetic signatures that are strongly associated with maritime ecosystems, including reliance on marine-derived food sources such as salmon (Oncorhynchus spp). These populations show clear genetic, ecological, and behavioural differentiation from interior wolves, consistent with long-term local adaptation and ecological divergence in coastal environments.⁵ ⁶ ⁷ ⁸ ⁹

Wolf as an ecotype

These genetic, ecological, and behavioural differences are often described in terms of ecotypes. An ecotype is a genetically distinct population within a species that has adapted to particular environmental conditions. Ecotypes arise when populations experience different ecological pressures, such as climate, prey availability, or habitat structure, leading to genetic differences associated with those environments.¹⁰ ¹¹ ¹² ¹³ ¹⁴ Although ecotypes are genetically distinct, they are not separate species and can usually interbreed where their ranges overlap.¹⁵ ¹⁶¹⁷ ¹⁸

A useful contrast can be found in killer whale (Orcinus orca) populations along the coast of British Columbia. Bigg’s (transient) and Resident killer whale ecotypes are genetically, socially, and culturally distinct, and despite overlapping ranges, there is no evidence that they interbreed. This separation is maintained through strong social structures, distinct vocalizations, dietary specializations, and learned behaviours that are passed down through generations, effectively creating reproductive isolation without physical barriers.¹⁹ ²⁰ ²¹ ²²

Wolf as a subspecies

Over the past 250 years, grey wolves have been classified into many subspecies, with as many as 38 proposed globally, 14 of which are now considered extinct.²³ In North America, Hall (1982) recognized 24 subspecies, but was later simplified to five primary subspecies²⁵. Another look at wolf taxonomy. Ecology and conservation of wolves in a changing world. Pages 375-398. Edited by Carbyn LN, Fritts SH, Seip DR. Canadian Circumpolar Institute, Occasional Publication Number 35, University of Alberta.[/efn_note]: Arctic wolf (Canis lupus arctos), northwestern wolf (C. l. occidentalis), Great Plains wolf (C. l. nubilus), Mexican wolf (C. l. baileyi), and eastern timber wolf (C. l. lycaon), though some debate the eastern timber wolf should be a distinct species, the eastern wolf (Canis sp. cf. lycaon). Eastern wolves, specifically, have been the subject of significant controversy, being viewed as either a distinct taxonomic (Canis lycaon) entity of conservation concern or a recent hybrid of coyotes (C. latrans) and grey wolves (C. lupus).²⁶ ²⁷ ²⁸

Many wolf subspecies in North America are disputed, as most lack sufficient differentiation. Hall (1981) identified three western coastal subspecies – C. l. ligoni in southeast Alaska, C. l. fuscus in coastal British Columbia, and C. l. crassodon on Vancouver Island – based on morphological differences. However, later revisions grouped all coastal wolves into the Great Plains wolf subspecies C. l. nubilus.²⁹ Recent genetic studies challenge this classification, showing that coastal wolves in British Columbia and southeast Alaska are distinct from interior populations. Notably, Munoz-Fuentes et al. (2009) found greater genetic differentiation between coastal B.C. wolves and other North American subspecies than among subspecies themselves, supporting recognition of C. l. fuscus for coastal wolves.

Although conceptually related, subspecies and ecotypes serve different roles and are defined in distinct contexts. Subspecies can carry formal legal protections, such as the Mexican grey wolf under the U.S. Endangered Species Act, whereas ecotypes generally do not, even when they represent ecologically critical populations. While subspecies and ecotypes can overlap, ecotypes are not formally recognized in taxonomy and are defined primarily by ecological adaptation rather than strict genetic classification. In practice, understanding wolves as ecotypes is often more useful for guiding conservation and management decisions, as it emphasizes how populations function within their specific environments rather than just their taxonomic classification.³⁰

Ecotype variation in wolves

Ecologically, two primary wolf ecotypes are recognized in British Columbia. The interior or Northern Rocky Mountain (NRM) forest ecotype occupies the Rocky Mountains and interior plateaus, characterized by larger body sizes and a dietary reliance on large ungulates such as moose, elk, caribou, and deer. In contrast, the coastal rainforest ecotype is generally smaller, exhibits strong site fidelity to marine-influenced landscapes, and consumes a diverse diet including salmon, intertidal invertebrates, marine mammals, and deer. Coastal wolves are typically found west of BC’s Coast Mountain Range, which separates coastal from interior areas of the province. In BC, this includes the Great Bear Rainforest, many islands and archipelagos in the Salish Sea, Vancouver Island, and along BC’s coast,³¹ with their range extending northward through the contiguous temperate rainforests of coastal Southeast Alaska.³² Their ecological specialization, combined with genetic differentiation from interior populations, has led some researchers to propose that coastal wolves constitute a distinct Ecologically Significant Unit (ESU).³³ Wolves currently re-occupying southern British Columbia predominantly display the phenotypic and behavioural traits of the interior ecotype, although access to coastal habitats presents future opportunities for both ecological adaptation and gene flow between the two forms.

Interactions Between Rocky Mountain and Coastal Wolves

Interactions between Rocky Mountain and coastal wolves are characterized by a gradual genetic and ecological transition rather than a discrete boundary.³⁴ ³⁵ Rocky Mountain wolves act as the primary source of recolonization, dispersing through mountain corridors, while coastal wolves retain distinct genetic and ecological identities with limited hybridization where ranges overlap. Molecular studies indicate that gene flow remains relatively high across the mountainous interior but declines toward the Pacific coast, where marked genetic differentiation emerges. This gradient likely reflects both geographic barriers, including mountain ranges and waterways, and ecological partitioning between marine-influenced and terrestrial ecosystems. Together, these dynamics create a mosaic of partial admixture and adaptive differentiation shaped by dispersal opportunities and strong habitat-driven selection.³⁶

What genetics can tell us

Genetic studies can examine population relationships at multiple levels. Broad genomic approaches analyze the complete DNA sequence of an organism, including nuclear DNA inherited from maternal and paternal sources, providing detailed insight into population structure, gene flow, and evolutionary history.³⁷ However, these methods require high-quality samples and extensive laboratory resources.

Within this genomic framework, single-nucleotide polymorphisms (SNPs), which are small variations at individual positions in the genome, are commonly used to generate high-resolution data on population structure, admixture, and connectivity. While powerful, SNP-based approaches also depend on higher-quality DNA (i.e. fresher scat) and more intensive processing.

Consequently, many wildlife studies rely on mitochondrial DNA (mtDNA) to investigate population history and lineage patterns.³⁸ mtDNA is inherited through the maternal line and can be used to identify haplotypes, which are distinct genetic variants that reflect shared maternal ancestry. Because mtDNA is more easily recovered from non-invasive samples such as scat, haplotype analysis remains a widely used approach for examining broad patterns of genetic distribution and lineage in wildlife populations.

Conservation implications

In summary, the recovery of grey wolves in southern British Columbia is largely driven by dispersal from interior Rocky Mountain populations, with limited but ecologically meaningful interactions with coastal lineages. These processes are generating a complex and evolving landscape of genetic and ecotypic variation. While continued range expansion may increase opportunities for admixture, the persistence of habitat-specific selection is likely to maintain ecotypic differentiation across the region.

Understanding the ecotype of reoccupying wolves is important for conservation and management. Wolves from distinct ecotypes, such as coastal rainforest wolves or interior/NRM forest wolves, may carry adaptations that influence habitat use, diet, movement, and ecological roles within the landscape.³⁹ ⁴⁰ In parallel, interactions between coastal and interior wolves may result in admixture, where individuals from different lineages interbreed. This can increase genetic diversity and potentially enhance the resilience of wolf populations in changing environments. However, extensive mixing between ecotypes could also reduce the genetic distinctiveness of coastal wolf populations.⁴¹ Understanding the lineage composition of re-establishing wolves can therefore guide strategies that balance ecological function with the preservation of unique genetic traits.⁴²

Suggested citation

Robertshaw C, Greer C, Paquet PC. 2026. Genetic legacy and ecological differences of grey wolves (Canis lupus) in southern British Columbia. Raincoast Conservation Foundation. https://doi.org/10.70766/23.7573