Biogeography of boreal passerine range dynamics in western North America: past, present, and future

Ecography: Pattern and Diversity in Ecology
By: , and 



Many of the Neotropical migrant bird species that breed throughout the Canadian boreal region are not found in the Alaskan boreal region, separated by the northwestern cordilleran mountains, despite the presence of climatically suitable habitat. We asked whether biological or climatic factors constrain certain species from crossing this geographic barrier. Analyzing a comprehensive dataset for 80 boreal passerine species, we used phylogenetic logistic regression to evaluate the relative importance of physical, migratory and competition metrics versus current and paleoclimatic suitability factors. Controlling for current climatic suitability within boreal Alaska, we found that species with the greatest climatic suitability across the northwestern cordillera, presently and also during the mid-Holocene period, were most likely to be regular breeders in the Alaskan boreal region. Migratory strategy also played a role, but could not be disentangled from its strong phylogenetic basis. Our analysis suggests that the perceived barrier of the northwestern cordillera may be easily weakened as climate change improves conditions there for many forest species. The weakening of this barrier may lead to relatively rapid range expansions and the reshuffling of species communities. Species’ realized distributional shifts will be a function of the interplay between a changing climate and static topographic features.

Publication type Article
Publication Subtype Journal Article
Title Biogeography of boreal passerine range dynamics in western North America: past, present, and future
Series title Ecography: Pattern and Diversity in Ecology
DOI 10.1111/ecog.02393
Volume 40
Issue 9
Year Published 2017
Language English
Publisher Wiley
Contributing office(s) Alaska Science Center Biology WTEB
Description 17 p.
First page 1050
Last page 1066
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