A nunatak is a type of glacial refugia that is located on the snow-free, exposed peaks of mountains, which lie above the ice sheet during glaciations. The identification of ‘diversity hotspots' in areas, which should have been migration regions during major glacial episodes, is evidence for nunatak glacial refugia. For example, the Monte Rosa mountain ranges, the Avers, and the Engadine and the Bernina are all floristically rich proposed nunatak regions, which are indicative nunatak glacial survival.