Insect faunal response to environmental changes during the last interglacial in Western Beringia

Reconstruction of the last interglacial (LI) environment could help us understand the mammoth faunal extinction and facilitate predictions of the effects of future on ecosystems. This work applied the fossil insect method to a number of interglacial sites in the Siberian Arctic (West Beringia). The main problem of the LI in Western Beringia is uncertain age determinations; many interesting sites are undated. Interpretation of “warming” signals is also problematic because of the special character of regional Pleistocene interglacial insect communities; these faunas are different from the modern ones. Investigation can clearly recognize interglacial faunas and, with additional stratigraphic evidence, correlate some units to the LI. Insect study helps shed light on the survival of large grazing mammals in Western Beringia during LI: 1) steppe-tundra areas remained in the forested regions; 2) climate change provided sufficient warmth to support the steppe-tundra environment in the north. Early Holocene climate change, in combination with marine transgression, progressively reduced suitable habitats for large mammals until a critical point was reached. Insect populations were also affected, but due to their small size, many steppe-tundra insect species remained as relicts in isolated patches of steppe-tundra.