My approach: biogeography seen from a geological perspective
The distribution of many modern terrestrial species can be explained by a handful amount of large-scale dispersals and that these episodes will likely become more numerous under climatic stress. The chronology of past dispersals, recorded in paleontological archives, has historically been used to date the assembling or dismantling of continental landmasses; it has played a critical role in the validation of plate tectonics and is a key to understand modern biogeography. However, the underlying mechanisms governing past and modern dispersals remain nebulous. Recent advances in paleontology and paleogeography have shown that the creation and disappearance of land bridges alone often fail to explain episodes of faunal dispersal.
My work relies on an integrated approach to paleo-biogeography that considers landscape beyond the position of continental landmasses and shorelines; I reconstruct the evolution of past dispersal corridors by incorporating paleo-topography, paleoenvironments, and overwater dispersal routes to paleogeography. The reconstruction of dispersal corridors, integrated with paleontological data, contributes to developing a new science of species dispersal and diversification in deep time, while solving the chronological and mechanistic enigma of some of the most important dispersal events of the paleontological record.
The nature of this work is multidisciplinary – a requirement while working in biogeography. I have been immersed in biogeography and multi-disciplinarity since my PhD, focused on the paleoenvironmental and paleogeographical context of the anthropoid primates of Myanmar. As a sedimentary geologist, I decipher terrestrial sedimentary archives to reconstruct past climates and landscapes, while relying on biologists and paleontologists to complete my expertise in biogeography.
Many of my research projects focus on the Paleogene period (66-34 million years ago) because it is a period with numerous and intense climatic events and paleogeographic changes associated with many discrete dispersal events. The Paleogene also provides interesting analogues for the on-going climate changes -with impressive shifts in atmospheric concentration in carbon dioxide, ice sheet extent and global temperature. I have been focusing on six different projects:
–The evolution of past monsoons
–The paleogeography of South Asia
–The evolution of the North American Cordillera
–The Paleogene Biogeography of the Neotethyan margin
–The Grande Coupure in Southern Europe
–The dispersal of early anthropoid primates
Tools
My projects share the common theme that they use sedimentary geology, geochemistry, and geochronology tools applied on continental rocks as proxies for reconstructing past environments and paleogeography.
The tools I commonly use include:
–Stable and clumped isotope geochemistry to reconstruct paleoclimates.
–Basin Geology, clastic sedimentology & pedology to interpret past depositional environments.
–U-Pb, Nd & Sr geochronology to date sedimentary rocks and study their provenance.
Alexis Licht 