Diversity and Habitat Associations of Subarctic Small Mammal Assemblages in the Yukon’s Tombstone Territorial Park

Small mammals play a central role in northern ecosystems, yet their diversity and habitat associations remain poorly documented in the subarctic mountains of northwestern Canada. I assessed small mammal assemblages across elevational and habitat gradients in Tombstone Territorial Park, located in the Taiga Cordillera Ecozone. My objectives were to document small mammal diversity and habitat associations. In 2005, small mammals were sampled at 27 sites representing seven common habitat types, ranging from lowland boreal forest to subalpine shrublands and alpine tundra. Twelve species of voles, lemmings, mice, and shrews were captured. Species richness and relative abundance were highest in lowland habitats and declined with increasing elevation. Alpine habitats supported fewer, highly specialized species. Several species were restricted to lowland habitats, whereas two species occurred exclusively in alpine tundra. Canonical correspondence analysis revealed a separation of species assemblages based primarily on moisture. These findings demonstrated that moisture, elevation, and habitat type structured small mammal assemblages in this northern mountain landscape. As a first approximation of small mammal assemblages in the Taiga Cordillera Ecozone, I provide a historical baseline for detecting recent and future ecological change. Climate change may facilitate the range expansion of lowland species and alter alpine assemblages, with potential consequences for community composition, trophic interactions, and ecosystem processes, highlighting the importance of small mammal monitoring in a rapidly warming subarctic.