Usually remnants of an original ecosytem surviving in isolated or discrete areas. They are areas which have not undergone ecological change in environments that have undergone considerable change. They provide suitable habitat for species which may have once been distributed across an entire local environment or bioregion. It is a place that effectively protects species from the effects of severe environmental disruptions that, in the rest of their habitat range, lead to significant declines in biomass, mass death, or mass extinction.
(singular: Refugium) Areas that were unglaciated during the ice age, and thus served as refuges in which organisms could survive.
An area with relatively unaltered climate that is inhabitated by plants and animals during periods of large-scale climatic change (for example, glaciation) and that remains a center of relict forms from which the species disperse and speciation occurs once the climate reverts.