UBC Theses and Dissertations
Examining the influence of climate change on distribution shifts and the efficacy of protected areas for hummingbirds in British Columbia Kennedy, Tabitha
Climate change continues to alter ecological systems, fauna, and flora within Canada. Many species are predicted to undergo range shifts as they track changing environmental conditions. Such range shifts add complexity to protected area (PA) planning if coverage within PA networks is reduced. In my MSc thesis, I assessed potential future distributions for a climate-sensitive family, Trochilidae (Hummingbirds), and the effectiveness of protected areas in tracking their shifting distributions. Following a maximum entropy approach, I modelled current and future species distribution for four commonly occurring species across British Columbia (B.C.): Anna’s Hummingbird (Calypte anna), Black-chinned Hummingbird (Archilochus alexandri), Calliope Hummingbird (Selasphorus calliope), and Rufous Hummingbird (Selasphorus rufus). Models included climatic, ecological, and geographic variables and were built using citizen science observations (eBird program) from 1981 to 2020 to assess the impact of climate (direct) and climate-induced habitat change (indirect) on potential future distributions. I found that climate-related variables were the strongest predictors of distribution for all species. Under the Representative Concentration Pathway (RCP) +8.5 W/m² climate warming scenario, northward range expansions were projected for all four hummingbird species. Absolute protected area coverage was projected to increase for all species following range expansions (Anna’s: +6,378 km², Black-chinned: +20,952 km², Calliope: +23,829 km², Rufous: +31,619 km²), while relative protected area coverage was projected to increase for all species (Calliope: +1.6%, Black-chinned: +2%, Anna’s: +10.8%) except for Rufous Hummingbird (– 3.8%). Greater range overlap was also projected to occur as a result of range expansion within the province. My findings indicate that while some future range expansion is predicted to fall within the boundaries of protected areas, a higher degree of range expansion is predicted to occur outside these boundaries in non-protected areas. Hence, future conservation efforts for declining species such as the Rufous Hummingbird will benefit from strengthened habitat protection and conservation measures within, but especially outside the boundaries of protected areas. Future studies will be needed to address the implications of greater interspecific range overlap among breeding hummingbird species in B.C., and whether native vegetation that contributes key floral resources to hummingbirds will follow similar range shifts.
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