refuge

A restricted and isolated area in which plants and animals persisted during a period of continental climatic change that made surrounding areas uninhabitable; especially an ice-free or unglaciated area within or close to a continental ice sheet or upland ice cap, where hardy biotas eked out an existence during a glacial phase. It later served as a center of dispersal for the repopulation of surrounding areas after climatic readjustment. (Source: BJGEO)