The problem of geographic origin and immigration routes of biota occurring in north-western Scandinavia in the latter part of the Wiirm glaciation is intimately connected with the development of the environments after the culmination of the Full Glacial period. Analyses of environments in Antarctica and their biotic communities give certain clues. In nunataks and temporary oases surrounded by ice there might have existed ecosystems, viz. chalico-systems and bryo-systems, consisting of a few species resistant