Glacial refugium
A glacial refugium (plural refugia) is a geographic region which made possible the survival of flora and fauna during ice ages and allowed for post-glacial re-colonization. Different types of glacial refugia can be distinguished, namely nunatak, peripheral, and lowland. Glacial refugia have been suggested as a major cause of floral and faunal distribution patterns in both temperate and tropical latitudes. With respect to disjunct populations of modern-day species, especially in birds, doubt has been cast on the validity of such inferences, as much of the differentiation between populations observed today may have occurred before or after their restriction to refugia. In contrast, isolated geographic locales that host one or more critically endangered species (regarded as paleoendemics or glacial relicts) are generally uncontested as bona fide glacial refugia.