Modern African ecosystems as landscape-scale analogues for reconstructing woody cover and early hominin environments.

Reconstructing habitat types available to hominins and inferring how the paleo-landscape changed through time are critical steps in testing hypotheses about the selective pressures that drove the emergence of bipedalism, tool use, a change in diet, and progressive encephalization. Change in the amount and distribution of woody vegetation has been suggested as one of the important factors that shaped early hominin evolution. Previous models for reconstructing woody cover at eastern African hominin fossil sites used global-scale modern soil comparative datasets.

Diets of mammalian fossil fauna from Kanapoi, northwestern Kenya.

Carbon isotope ratios of mammalian teeth from the Kanapoi site in northern Kenya are interpreted in the context of C and C derived resources to investigate the paleoecology of Australopithecus anamensis. δC values of large mammals, when compared at the taxon level, show an ecosystem that is strongly biased towards mixed feeders and browsers. However, sufficient C resources were present such that some C dominated grazers were also present in the large mammal fauna.

Aridity and hominin environments.

Aridification is often considered a major driver of long-term ecological change and hominin evolution in eastern Africa during the Plio-Pleistocene; however, this hypothesis remains inadequately tested owing to difficulties in reconstructing terrestrial paleoclimate. We present a revised aridity index for quantifying water deficit (WD) in terrestrial environments using tooth enamel δO values, and use this approach to address paleoaridity over the past 4.4 million years in eastern Africa.

Hippopotamus (H. amphibius) diet change indicates herbaceous plant encroachment following megaherbivore population collapse.

Megaherbivores (>1000 kg) are critical for ecosystem health and function, but face population collapse and extinction globally. The future of these megaherbivore-impoverished ecosystems is difficult to predict, though many studies have demonstrated increasing representation of C3 woody plants. These studies rely on direct observational data, however, and tools for assessing decadal-scale changes in African ecology without observation are lacking.

Stable isotopic variation in tropical forest plants for applications in primatology.

Stable isotope analysis is a promising tool for investigating primate ecology although nuanced ecological applications remain challenging, in part due to the complex nature of isotopic variability in plant-animal systems. The aim of this study is to investigate sources of carbon and nitrogen isotopic variation at the base of primate food webs that reflect aspects of primate ecology. The majority of primates inhabit tropical forest ecosystems, which are dominated by C3 vegetation.

Dietary changes of large herbivores in the Turkana Basin, Kenya from 4 to 1 Ma.

A large stable isotope dataset from East and Central Africa from ca. 30 regional collection sites that range from forest to grassland shows that most extant East and Central African large herbivore taxa have diets dominated by C4 grazing or C3 browsing. Comparison with the fossil record shows that faunal assemblages from ca.

Paleoenvironmental context of the Middle Stone Age record from Karungu, Lake Victoria Basin, Kenya, and its implications for human and faunal dispersals in East Africa.

The opening and closing of the equatorial East African forest belt during the Quaternary is thought to have influenced the biogeographic histories of early modern humans and fauna, although precise details are scarce due to a lack of archaeological and paleontological records associated with paleoenvironmental data. With this in mind, we provide a description and paleoenvironmental reconstruction of the Late Pleistocene Middle Stone Age (MSA) artifact- and fossil-bearing sediments from Karungu, located along the shores of Lake Victoria in western Kenya. Artifacts recovered from surveys and controlled excavations are typologically MSA and include points, blades, and Levallois flakes and cores, as well as obsidian flakes similar in geochemical composition to documented sources near Lake Naivasha (250 km east).

Environments and trypanosomiasis risks for early herders in the later Holocene of the Lake Victoria basin, Kenya.

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.

Diet of Theropithecus from 4 to 1 Ma in Kenya.

Theropithecus was a common large-bodied primate that co-occurred with hominins in many Plio-Pleistocene deposits in East and South Africa. Stable isotope analyses of tooth enamel from T. brumpti (4.

Detecting intraannual dietary variability in wild mountain gorillas by stable isotope analysis of feces.

We use stable isotope ratios in feces of wild mountain gorillas (Gorilla beringei) to test the hypothesis that diet shifts within a single year, as measured by dry mass intake, can be recovered. Isotopic separation of staple foods indicates that intraannual changes in the isotopic composition of feces reflect shifts in diet. Fruits are isotopically distinct compared with other staple foods, and peaks in fecal δ(13)C values are interpreted as periods of increased fruit feeding.