Climate-Driven Range Shifts of the Sharp-Tailed Grouse Tympanuchus phasianellus

Abstract. In this study, we tested whether the Sharp-tailed Grouse Tympanuchus phasianellus experienced rapid demographic expansion and shifts in its distribution from the Last Glacial Maximum to the present and to the future. For this, we integrated two different approaches, phylogeography and ecological niche modeling, to understand the historical demography and the future of the Sharp-tailed Grouse under climate change scenarios. To this end, we re-analyzed two published mitochondrial DNA datasets to provide a comprehensive DNA characterization of populations across the range of this species. We used ecological niche models in tandem with landscape genetics to estimate the species current and historical geographic range, and to summarize effective connectivity among populations of the species at present. We found low genetic variation across the Sharp-tailed Grouse's distributions with almost no differentiation among subspecies. The haplotype network was consistent with star-shape topologies and showed no evident phylogeographic structure with the typical signature of recent demographic expansion. Taken together with the ecological niche modeling results, study outcomes supported the ‘expansion-contraction' model of Pleistocene biogeography. A unique result of this study was an apparently complete range shift of this species between the Last Glacial Maximum and the present, and a signature of cryptic refugium located in Alaskan territory in North America. The usual reason for lack of phylogeographic structure is broad dispersal, rapid expansion, and panmixia. However, in view of our novel geographic insights, a simpler explanation may be very recent establishment of the species’ range. The future predictions confirmed that the Sharp-tailed Grouse continues climate-driven range shifts in 2050 and 2070.