Abstract
Humans evolved in response to the availability of plant and water resources over space and through time. Their influence on our species’ evolution is debated, though, because archives of their spatial distribution are scarce at early human (hominin) localities. Meter-scale vegetation patterns are revealed from sedimentary plant biomarkers across an archaeological horizon at Olduvai Gorge (FLK
Zinj
). Biomarkers evince a varied local landscape with a woodland patch near a small freshwater wetland, surrounded by an open grassland landscape. Biomarkers from the wetland indicate diverse edible plants near potable water. The coexistence of butchered large animal bones and hominin remains, including juveniles, within an isolated biomarker-delineated wooded microhabitat at FLK
Zinj
provide support for early provisioning behaviors by our ancestors.
The availability of plants and freshwater shapes the diets and social behavior of chimpanzees, our closest living relative. However, limited evidence about the spatial relationships shared between ancestral human (hominin) remains, edible resources, refuge, and freshwater leaves the influence of local resources on our species’ evolution open to debate. Exceptionally well-preserved organic geochemical fossils—biomarkers—preserved in a soil horizon resolve different plant communities at meter scales across a contiguous 25,000 m
2
archaeological land surface at Olduvai Gorge from about 2 Ma. Biomarkers reveal hominins had access to aquatic plants and protective woods in a patchwork landscape, which included a spring-fed wetland near a woodland that both were surrounded by open grassland. Numerous cut-marked animal bones are located within the wooded area, and within meters of wetland vegetation delineated by biomarkers for ferns and sedges. Taken together, plant biomarkers, clustered bone debris, and hominin remains define a clear spatial pattern that places animal butchery amid the refuge of an isolated forest patch and near freshwater with diverse edible resources.