LD 350-1, the earliest specimen of the genus Homo, from Ledi-Geraru, Ethiopia
Reconstructed distribution of plains zebra during the Last Glacial Maximum
Skull of the giant saber-tooth felid Homotherium from Hadar, Ethiopia
Modern giraffe at the Smithsonian National Museum of Natural History
Early hominin paleoecology
I study the paleoecology of early hominins in eastern Africa using a variety of methods, including stable isotopes of herbivore tooth enamel, dental wear (microwear, mesowear), ecomorphology, and community structure analyses. This work provides a critical contextual and comparative framework for interpreting the hominin fossil record and the role of different drivers in shaping hominin paleobiology and behavioral and cultural innovations.
Climatic influences on mammal distributions
Temporal turnover (origination and extinction) and range shifts (immigration and extirpation) in the mammalian and hominin fossil record are often causally linked to climatic or habitat change. Drawing such causal links between environmental change and species turnover, however, assumes that mammal species are constrained in their environmental niches. I use modern mammal species and their associations with climate, habitat, and ecosystem-level data to assess the degree to which mammal species distributions and community composition are a product of climate and environments. These methods primarily focus on species distribution models, among others.
Emergence of modern mammal communities
Mammal communities and herbivore and carnivore guilds in eastern Africa today are both taxonomically and functionally depauperate compared to those of the Plio-Pleistocene. Although both the herbivore and carnivore guilds winnow in diversity through time, the exact sequence and rate of this diversity loss and its underlying causes remain unclear. I use a variety of methods, including functional trait community structure, predator-prey network analyses, and simulations of faunal turnover to address these questions.
Plio-Pleistocene ruminant evolution
I am especially interested in the evolution of African artiodactyls (e.g., bovids, giraffids, hippopotamids, and suids) and ruminants (bovids and giraffids) in particular. Artiodactyls are the cornerstone of mammal communities in eastern African savannas – they are the most diverse and abundant herbivores, making them the primary liaison between plant productivity and the higher trophic levels. Documenting their past diversity through time and space is a critical step to understanding paleo-ecosystems and the history of those today.