Surviving glaciations at the edges of the Empire

Three main hypotheses may explain the distribution of alpine and arctic endemic plants: a) distribution reduction follewed by a post-glacial expansion; b) distribution expansion follewed by a post-glacial reduction; c) stable distribution with ocal bufferig from extreme environmental effects. The theree hypotheses were tested in recent years on differet plants endemic to the Ligurian and Maritime Alps, giving evidences of the implementation of all three hypotheses. However, in areas less affected by glaciations, the genetic patterns of endemic species may not result from the effect of last glacial period but from cumulative effects of recent and Tertiary changes.