Abstract
Climate change is expected to threaten endemic plants in the Alps. The aim of my thesis was to assess the impact of future projected climate change on eight alpine endemic species in the Dolomites and to describe the population genetic and phylogeographical patterns for three rare alpine endemic species in order to understand their populations responses to the Quaternary climate changes. Firstly, I estimated the current species distribution and I modeled predictive maps under different climate change scenarios using downscaled climatic data at a fine spatial resolution of 50m, as well as topographic factors, to unravel areas of future stability of climatic suitability for eight alpine narrow endemics of the Dolomites. Furthermore, I investigated some factors that may modulate species responses at a local scale. Secondly, I investigated the intraspecific genetic patterns of three species, Campanula morettiana Rchb., Primula tyrolensis Schott ex Rchb. and Saxifraga facchinii Koch, to clarify their phylogeography and to shed light on both the location of possible glacial refugia and the post-glacial range expansions routes. The negative impact of future projected climate change ranged from moderate to severe, depending on scenario and species. Generally, range loss occurred at the lowest elevations, while gained and stable areas were located at highest elevations. Our findings supported the role of topographic heterogeneity in maintaining climatic microrefugia, however, the peculiar topography of the Dolomites, characterized by high altitude plateaus, resulted in high climate change velocity in areas of projected future climatic suitability. Then, the improved phylogeographical analyses based on RADseq data from a range-wide populational sampling allowed to unravel the genetic structure and to reconstruct the post-glacial history of the study species. C. morettiana and P. tyrolensis showed a strong intraspecific structure with a clear differentiation among eastern and western populations on either side of the Piave valley. The southern and southeastern Dolomites provided areas of peripheral refugia for both the species. However, northern refugia were more likely for C. morettiana, while northern and southwestern populations of P. tyrolensis showed a putative late immigration. The more cold adapted S. facchinii showed a strong intraspecific genetic structure with highly differentiated populations also over short distances, congruent with local nunatak survival, with the northern and northeastern edge populations showing marked genetic isolation. The Dolomites iii provided areas of nunatak glacial refugia for S. facchinii also in the central and northern edges, while the southern and southeastern Dolomites provided peripheral refugial areas for montane to alpine species. In conclusion, the present study constitutes an original contribution to the knowledge of the endemic flora of Dolomites. In particular, the results of my research can be useful for the elaboration of proactive conservation strategies within this center of endemism to ensure the survival of these unique rare species facing future climate change.