Abstract
At northern temperate latitudes trees haveadjusted their ranges substantially in response to changingclimates during the Holocene. Results from dispersalmodel simulations suggest that postglacial migration ratesmay have been over-estimated from fossil pollen data. As acontribution to this debate, we infer the migration rates ofAbies alba(Mill.), silver fir, as a case-study species, byusing a spatially explicit approach based on fossil pollenbut taking into account its modern genetic diversity pattern. Maximum estimates of migration rates from fossil pollendata alone are higher than 700 m yr-1during the Holocene.Considering the potential refugia as suggested from all thefossil data but restricting the area over which silver firexpanded from each glacial refugium using data on thecurrent haplotype distribution, the estimated maximummigration rates of silver fir are less than 250 m yr-1.Genetic information may allow for (1) the exclusion of thoserefugial areas where the species may have survived duringthe last glacial period but from which it did not spread orspread only very locally and (2) the delineation of the areas. over which the species spread from each glacial refugium.The estimated rates in the present study are generally con-sistent with rates suggested from modelling approaches.This study shows that integrating fossil pollen records canimprove simulations of dispersal processes and, thus, allowfor better predictions of future changes in tree species’ranges.