2025/09/08 by Jeremy D. Mizel · 1 voice
Earth and Planetary Sciences · Environmental Science · #Climate change and permafrost #Rangeland and Wildlife Management #Cryospheric studies and observations
paper · doi:10.1080/15230430.2025.2546175
openalex publication_date 2025/09/08 · openalex created_date 2025/10/10 · openalex updated_date 2026/06/14
Assessments of passerine–habitat relationships in shrub tundra regions are rare, limiting our understanding of the effects of shrub expansion. Further, previous studies of shrub tundra passerines have primarily assessed variation in abundance as a function of deciduous shrub cover in the aggregate, which assumes a uniform response across shrub species. Here, I assess variation in the density of twelve shrub-adapted passerines as a function of Alnus, Betula, and upright Salix shrub cover at six above–tree line sites in sub-Arctic and Arctic Alaska. I also assess variation in the density of four tundra-adapted passerines as a function of lichen, wet sedge, Dryas dwarf shrub, and Eriophorum vaginatum cover. I fit models to passerine data collected from 2015 to 2024 consisting of the individual encounter locations, allowing fine-scale assessment of density under a point process framework. Passerines adapted to alpine tundra showed positive responses to lichen cover, whereas the lone arctic tundra species exhibited a positive response to Eriophorum vaginatum. With one exception, shrub-adapted passerines showed weak to negative responses to Betula shrub cover and strong, positive responses to Salix shrub cover. Thus, use of the genus-specific covariates has a greater capacity for explaining variation in bird density and for understanding the effects of shrub expansion.