Climate change refugia in Canadian prairies: assessing range shifts and identifying breeding habitats for grassland songbirds

The identification of climate change refugia is fundamental for climate-smart conservation planning, especially in highly altered landscapes, such as temperate grasslands. Our study aimed to identify breeding refugia for three focal grassland birds: Baird's sparrow (Centronyx bairdii), Sprague's pipit (Anthus spragueii), and thick-billed longspur (Rhynchophanes mccownii) across the Canadian prairies. We used species distribution models to identify breeding refugia within the climatically suitable range for two time periods (2050 and 2080) under two of the most likely climatic scenarios ("intermediate scenario" RCP 4.5 and "worst-case scenario" RCP 8.5). In doing so, we demonstrate the importance of incorporating species-specific dispersal ability and projected shifts in grassland habitats in the analyses. Our study predicts a northward shift in the breeding ranges of all three bird species under both climate scenarios, with almost 100% loss of their current breeding habitat. However, all species are expected to gain bioclimatic space outside of their current range under RCP 4.5 in 2050 and 2080. Further increases in emissions under the RCP 8.5 scenario will likely cause Baird's sparrow to lose bioclimatic space both in 2050 and 2080, and the same is true for the other two species only in 2080. Approximately 80% of currently suitable habitats for the focal species are located outside protected areas. As the climate warms, almost 100% of future breeding refugia for all birds are likely to reside outside protected areas in all climate change scenarios. Our study provides a framework for climate-integrated conservation planning for the wide-ranging migratory species.