Abstract
This project examines the implications of increasing shrub dominance on high-elevation bird populations in the Yukon. Shrubs are among the taxa expanding their habitat ranges farther north and to higher elevations as a result of increasing global temperatures, and high-elevation bird species that live and breed in subalpine and alpine-tundra habitats may be influenced by this increased shrubification. Species that live and breed in shrubby subalpine habitats may be positively associated with elements of shrub dominance and may benefit from increasing shrubification, but alpine specialists may be negatively affected as increasing shrub growth contracts alpine habitat at the tops of mountains.
In this project I examined the relationships between high-elevation bird species estimated abundance and elements of shrub dominance and shrub species along an elevational gradient on mountains in the Yukon Territory. I used autonomous recording units to record bird sounds in the subalpine and alpine on ten mountains and estimate the abundance of different bird species, and gathered ground vegetation data to estimate shrub height, density, and stem count at each sampling site. Results from direct and indirect gradient analyses showed that bird species, shrub height, and shrub species all drive habitat grouping, and identified specific bird species that are significantly associated with elements of shrub dominance and may be positively or negatively affected by increased shrubification. These results can offer information about birds of potential conservation concern as shrubs continue to increase in dominance on northern mountains in a changing climate. |
About the Author
Anna Jacobsen is currently pursuing a Master's of Science at the University of Alberta with Dr. Erin Bayne and C. Lisa Mahon. Her research revolves around elevation gradients on Yukon mountains, specifically how elements of shrub dominance may be affecting high-elevation bird species, and patterns of vocal activity for high-elevation birds during the breeding and post-breeding periods.
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