期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2015
卷号：112
期号：12
页码：3674-3679
DOI：10.1073/pnas.1423953112
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：SignificanceHerding was the earliest form of African food production and transformed local populations of people and animals. Herders migrated from eastern to southern Africa around 2,000 years ago, but only in small numbers. Zoonotic disease vectors, specifically the tsetse fly, which carries sleeping sickness, are thought to have impeded these movements. Archaeologists have argued that the presence of tsetse flies around Lake Victoria, Kenya, created a barrier that prevented migration and forced subsistence diversification. This study, using stable isotope analysis of animal teeth, reveals the existence of ancient grassy environments east of Lake Victoria, rather than tsetse-rich bushy environments. This overturns previous assumptions about environmental constraints on livestock management in a key area for southward movement of early herders. Specialized pastoralism developed [~]3 kya among Pastoral Neolithic Elmenteitan herders in eastern Africa. During this time, a mosaic of hunters and herders using diverse economic strategies flourished in southern Kenya. It has been argued that the risk for trypanosomiasis (sleeping sickness), carried by tsetse flies in bushy environments, had a significant influence on pastoral diversification and migration out of eastern Africa toward southern Africa [~]2 kya. Elmenteitan levels at Gogo Falls (ca. 1.9-1.6 kya) preserve a unique faunal record, including wild mammalian herbivores, domestic cattle and caprines, fish, and birds. It has been suggested that a bushy/woodland habitat that harbored tsetse fly constrained production of domestic herds and resulted in subsistence diversification. Stable isotope analysis of herbivore tooth enamel (n = 86) from this site reveals, instead, extensive C4 grazing by both domesticates and the majority of wild herbivores. Integrated with other ecological proxies (pollen and leaf wax biomarkers), these data imply an abundance of C4 grasses in the Lake Victoria basin at this time, and thus little risk for tsetse-related barriers to specialized pastoralism. These data provide empirical evidence for the existence of a grassy corridor through which small groups of herders could have passed to reach southern Africa.
关键词：archaeology ; carbon isotopes ; food production ; East Africa ; livestock disease
