Late Quaternary paleogeography and evolution of arctic breeding waders

This review Links published data on mitochondrial DNA phylogeography of three wader species breeding in the Arctic to the availability of suitable breeding habitat during the past 250 000 years. We argue that the breeding ranges of arctic waders were most restricted in size during warm phases in the earth's climate (interglacials), resulting in population bottlenecks in species breeding in the high arctic zone, such as Red Knot Calidris canutus and Ruddy Turnstone Arenaria interpres, and population contraction and the initiation of genetic divergence in low arctic species, such as Dunlin Calidris alpina. When the climate cooled, all species could spread over larger areas. However, large ice-sheets fragmented tundra habitat, which resulted in more differentiation. Subspecies of Dunlin that became isolated during or before the last glacial period are genetically distinct, while those that originated after the glacial cannot be distinguished using mitochondrial DNA. The sensitivity of waders breeding in the high Arctic to increases in global temperature raises concerns over the effect of possible global warming due to anthropogenic factors on these species.