Climate, ecology, and the spread of herding in eastern Africa Kendra L. Chritz a, * , Thure E. Cerling b , Katherine H. Freeman c , Elisabeth A. Hildebrand d , Anneke Janzen e , Mary E. Prendergast f a National Museum of Natural History, Smithsonian Institution, Washington, DC, 20560, USA b Department of Geology and Geophysics, Salt Lake City, UT, 84112, USA c Department of Geosciences, The Pennsylvania State University, University Park, PA, 16802, USA d Department of Anthropology, Stony Brook University, Stony Brook, NY,11794-4364, USA e Department of Archaeology, Max Planck Institute for the Science of Human History, 07745, Jena, Germany f Division of Humanities, Saint Louis University, Madrid, 28003, Spain article info Article history: Received 2 April 2018 Received in revised form 26 November 2018 Accepted 27 November 2018 Keywords: Africa Paleoecology Holocene Stable isotopes Herding Food production Monsoon Archeology abstract The spread of early herders across Africa is a pivotal event in prehistory, but the context of this event remains poorly understood due to a lack of paleoenvironmental data. We present new radiocarbon dates and multi-proxy Holocene paleoecological records for two distinct settings on the pathways through which livestock herding spread across eastern Africa: the Lake Turkana Basin, which has the earliest record of livestock in eastern Africa, and the Lake Victoria Basin, located farther south. Herbivore diet as inferred from tooth enamel carbon isotopes (n ¼ 368), and pollen and leaf wax biomarker data, do not support a uniform ecological response to increased aridity at the end of the African Humid Period ~5 kya, as had been previously thought. Rather, climate change had basin-specific ecological effects, and these in turn met differing human responses. Rather than extrapolating local ecological effects from regional climate records, archaeologists require basin-specific paleoecological data, deeply integrated with archaeological findings. This paper provides such integration for the first time in eastern Africa. Our results highlight the climatologically and ecologically distinctive areas around lake margins, necessi- tating future paleoenvironmental and archaeological research in inland areas. © 2018 Elsevier Ltd. All rights reserved. 1. Introduction Much attention has been given to understanding the processes governing ecological change in eastern Africa over geologic time, and how such change is reflected in the archaeological record (Potts, 2013; deMenocal, 2013). These discussions have focused on the role of orbital forcing (Claussen et al., 1999; deMenocal et al., 2000) in shaping ecosystem structure over time (deMenocal, 2011; Magill et al., 2013a), and the relationship between solar insolation and the abundance of C 3 (woody trees, shrubs, and forbs) vs. C 4 (lowland tropical grasses) plants. Paleoecologists employ proxies such as pollen, leaf wax biomarkers, and stable isotopes in herbivore tooth enamel and soil carbonates to create paleoenvir- onmental reconstructions, but these proxies are rarely analyzed in conjunction with one another in terrestrial environments (Levin, 2015). African climate is primarily driven by the precession of the equinoxes, which dictates the location and convective strength of the intertropical convergence zone (ITCZ) (Kutzbach, 1981; Berger and Loutre, 1997; Battisti and Naylor, 2009) (Appendix Figure A.1). The ITCZ moves seasonally across the equator, influ- encing seasonal rainfall due to differential heating between land and sea. When Northern Hemisphere peak solar insolation occurs, the ITCZ strengthens and intensifies the monsoon system (Nicholson, 1996). During the early Holocene (11.7e8.2 kya; following Holocene formal stratigraphic designations of Walker et al. (2012)), precessionally-driven high Northern Hemisphere insolation resulted in mesic conditions known as the African Hu- mid Period (AHP), which persisted until falling insolation weak- ened the monsoons around 5 kya (Kutzbach, 1981; deMenocal et al., 2000; Costa et al., 2014). The global climate changes and local ecological shifts of the early and middle Holocene constitute the setting for diverse tran- sitions from hunting/gathering to food production in different parts * Corresponding author. National Museum of Natural History Smithsonian Institution, 10th and Constitution Avenue NW, Washington, DC, 20560, USA. E-mail address: ChritzK@si.edu (K.L. Chritz). Contents lists available at ScienceDirect Quaternary Science Reviews journal homepage: www.elsevier.com/locate/quascirev https://doi.org/10.1016/j.quascirev.2018.11.029 0277-3791/© 2018 Elsevier Ltd. All rights reserved. Quaternary Science Reviews 204 (2019) 119e132