The Carabidae of the Glacial Refuge in the British Isles and their Contribution to the Post Glacial Colonization of Scandinavia and the North Atlantic Islands

Abstract

During the past twenty years a systematic investigation of subfossil remains of Coleoptera has shown that for most, if not all, of the Last (Wisconsinan) Glaciation a diverse insect fauna occupied the British Isles. The evidence is very sparse for the early phases of this period but since insect faunas can be shown from fossil evidence to have lived in the southern parts of these islands during the severest episode of the glaciation (about 18,000 years ago), when ice sheets covered the northernmost two thirds of the country, it is most likely that some insect fauna survived the entire glacial period in the British Isles. In other words, the southern parts of Britain acted as a glacial refuge. We know which species occupied this refuge, not from extrapolations back from present day geographical ranges but from the concrete data provided by their fossil remains. They may be dated stratigraphically or, in the cases of fossil assemblages from the last 45,000 years, by radiocarbon methods. The Carabidae make up an important part of these fossil insect faunas and include a considerable number of species whose presence in the relatively recent past in Britain could not have been suspected were it not for the fossil evidence.