Distributions of Plants in the Circumpolar Area in Relation to Ecological and Historical Factors

Abstract

Plant ranges in the northern circumpolar regions may be governed by climatic, edaphic, as well as historical factors. Survival during ice-ages plays an important role, indirectly by the geno-typical changes resulting from loss (or gains) of biotypes in refugia or during migrations. Many distributional areas which indicate radiations are not only the result of survival and later migration from the refugia, but they result from limitations by climatic factors. The discussion centers in plants with disrupted areas in particular the so-called centric (uni-, bri- and tricentric) distributions in Scandinavia, Greenland, and North America. It is concluded that most centric distributions give hardly any evidence of a perglacial survival. After the ice-age most species were able to spread again from the refugia and now occupy those parts where the ecological conditions are suitable. In Scandinavia as well as in Greenland the amphi-Atlantic areas and some very isolated occurrences seem to give evidences of a persistence during glacial epochs.