Quaternary insect fossils, paleoecology, paleoclimatology.
The reconstruction of paleoenvironments has been my principal research focus, particularly in the Beringian region. To date, I have studied insect fossil assemblages from 175 sites in North America and Europe, deriving data for use in paleoecological and paleoclimatic reconstructions. I am particularly interested in Pleistocene interglacial climates in the Arctic, as current research has documented the fact that global warming tends to be amplified in the polar regions. Since lowland regions of Beringia (north-eastern Siberia, the exposed Bering and Chukchi Sea shelves, Alaska and the Yukon Territory) remained ice-free during Pleistocene glaciations, this is essentially the only region where a terrestrial fossil record of glacial and interglacial environments has been preserved in the high latitudes.
It is increasingly important to develop quantitative estimates of past climates. This imperative has driven my research in several ways. My current research activities include two independent means of deriving calibrated, numerical estimates of past temperatures. One of these is the development of stable isotope (oxygen and hydrogen) analysis from fossil beetle chitin (with Darren Gröcke, McMaster University). The other is the continued refining of the Mutual Climatic Range method of paleoclimate estimation, which I developed for North American Quaternary insect assemblages. Finally, I am collaborating with Prof. Eske Willerslev, University of Copenhagen, and Dr. Ian Barnes, Royal Holloway, in the analysis of ancient DNA from fossil beetle remains, taken from permafrost sediments in Beringia. We have already recovered identifiable DNA from samples of fossil beetle chitin. This new avenue of research holds great promise for unravelling the biological history of the North.