The invasion of Northern Europe during the Pleistocene by Mediterranean species of Coleoptera

Abstract

Investigations of subfossil Coleoptera show that during the last few hundreds of thousands of years, species have remained evolutionarily constant. They have, however, altered their geographical distributions extensively in response to the climatic changes of the glacial/interglacial cycles. It can be demonstrated that many species which have today a Mediterranean range, extended their northern limits during the warmer interglacial and interstadial interludes, at least as far as the British Isles. These species comprised groups of varied ecological preferences and some have such restricted present day distributions that they have been viewed as ‘endemic’ Mediterranean species. Patterns of present day geographical distributions are thus the result of dynamic interaction between the species and the numerous and intense climatic changes that caused continuous biogeographic adjustments. This complex history can only be understood adequately by reference to the subfossils which provide the only objective evidence of where species lived in the geologically recent (and ecologically relevant) time.