Ecological niche differentiation across a wolf-coyote hybrid zone in eastern North America

AimHuman-caused habitat alteration and disturbance have promoted widespread loss of species' reproductive barriers, leading to hybridization and attendant changes in the distribution, abundance and interactions of most species. In theory, hybrids should have intermediate niche occupancy features compared to parental groups, thereby potentially leading to fundamental changes in the role of organisms in an ecosystem. Yet, there is a gap in our empirical understanding of how hybrids differ in their niche characteristics compared to parental types; this uncertainty is especially true for large carnivores that range over large spatial extents and have high behavioural plasticity in their niche characteristics or in the environments that they inhabit. We sought to test whether eastern wolf (Canis lycaon) - eastern coyote (C.latrans sp.) hybrids exhibited intermediate environmental niche characteristics compared to their progenitors. LocationEastern North America. MethodsWe integrated genetic profiling of georeferenced canid (eastern wolf, eastern coyote, hybrid) samples into species distribution models, to investigate relationships between canid genetic groups and their environment. We used relevant environmental variables to investigate niche overlap and niche breath of hybrids and their parental groups. ResultsSpecies distribution models revealed clear patterns of niche differentiation, with hybrids tending to occur in areas having intermediate environmental niche attributes and niche breadth, compared to parental groups. Niche overlap between hybrids and either parental group was greater than between the two parental groups, further highlighting the intermediate environmental niche that is occupied by hybrids. Main conclusionsWe show that even among wide-ranging and highly plastic large carnivores, hybrids tend to exhibit intermediate niche characteristics compared to parental groups. Our support for the intermediate phenotype hypothesis highlights its ecological relevance even when faced with coarse observational data, complex genetic structure, large spatial scale and high phenotypic plasticity.