The evolutionary history of the human lineage during the Plio-Pleistocene (~3 to 1 million years ago) is often linked to climatic and ecological change. This time period is well represented in the fossil and archaeological records in East Africa and includes some of the most important evolutionary and adaptive shifts in human evolution. While global climate history is relatively well understood, identifying local environmental change is critical for explaining why these developments occurred. Rainfall seasonality and local-scale variation in vegetation across space may represent fundamental drivers of evolutionary change; however, few empirical records are available to evaluate this perception.
The first aim of this study by doctoral student Scott Blumenthal, under the supervision of Dr. Thomas Plummer at CUNY, is to collect soils and mammal teeth from modern Ugandan environments to test the hypothesis that variation in rainfall seasonality and vegetation cover within and between habitats can be identified with stable isotopes. Sampling will be conducted in national parks and reserves in Uganda, including a wide range of environments, from forests to grasslands. This will provide a template for reconstructing these environmental conditions in the fossil record. The second aim of this study is to use stable isotope analysis of fossil soils and teeth from Plio-Pleistocene deposits of the Homa Peninsula, western Kenya, to produce a local environmental record through time, and evaluate hypotheses linking local environmental variability with human evolution. This under-studied but fossil- and artifact-rich region provides a geographically, geologically, and ecologically unique perspective on hominin evolution.
The proposed research will foster international collaborations with researchers and institutions in two East African countries. Collaboration with the Ugandan Wildlife Authority will provide opportunities to develop projects with the aim of adding ecological monitoring with stable isotope analysis to existing conservation management techniques. This project also will contribute to the education of an undergraduate intern, in addition to enhancing the graduate training of the co-PI.
