... particularlyon the influence of the frequent extinction and colonisa-tion events on the maintenance of genetic variation and on the partitioning of this variation within and amonglocal populations [8, ... parameter to evaluatedifferences in levels of diversity H across populations isthe coefficient of variation of H (standard deviation of HTable I. Continued.Populations Longitude Lattitude Groups ... other hand, Sorbus tormi-nalisis found in drier habitats, in the plains at lower lati-tudes, and is absent at high altitudes. Hence, it is likelythat during the last ice -age the climate was...