title: Woody cover and hominin environments in the past 6 million years.
abstract: The role of African savannahs in the evolution of early hominins has been debated for nearly a century. Resolution of this issue has been hindered by difficulty in quantifying the fraction of woody cover in the fossil record. Here we show that the fraction of woody cover in tropical ecosystems can be quantified using stable carbon isotopes in soils. Furthermore, we use fossil soils from hominin sites in the Awash and Omo-Turkana basins in eastern Africa to reconstruct the fraction of woody cover since the Late Miocene epoch (about 7 million years ago). (13)C/(12)C ratio data from 1,300 palaeosols at or adjacent to hominin sites dating to at least 6 million years ago show that woody cover was predominantly less than ∼40% at most sites. These data point to the prevalence of open environments at the majority of hominin fossil sites in eastern Africa over the past 6 million years.
authors.affiliation: University of Utah, Salt Lake City, Utah 84112, USA. thure.cerling@utah.edu
authors.forename: Thure E
authors.initials: TE
authors.lastname: Cerling
authors.forename: Jonathan G
authors.initials: JG
authors.lastname: Wynn
authors.forename: Samuel A
authors.initials: SA
authors.lastname: Andanje
authors.forename: Michael I
authors.initials: MI
authors.lastname: Bird
authors.forename: David Kimutai
authors.initials: DK
authors.lastname: Korir
authors.forename: Naomi E
authors.initials: NE
authors.lastname: Levin
authors.forename: William
authors.initials: W
authors.lastname: Mace
authors.forename: Anthony N
authors.initials: AN
authors.lastname: Macharia
authors.forename: Jay
authors.initials: J
authors.lastname: Quade
authors.forename: Christopher H
authors.initials: CH
authors.lastname: Remien
mesh_terms: D000351:Africa, Eastern; D000818:Animals; D005075:Biological Evolution; D002138:Calibration; D002247:Carbon Isotopes / Q000032:analysis; D017753:Ecosystem; D005580:Fossils; D005684:Gait / Q000502:physiology; D015186:Hominidae / Q000033:anatomy & histology / Q000502:physiology*; D010163:Paleontology; D018515:Plant Leaves / Q000254:growth & development; D006109:Poaceae / Q000254:growth & development; D011157:Population Dynamics; D012987:Soil / Q000737:chemistry; D014197:Trees / Q000254:growth & development; D014329:Tropical Climate; D055814:Wilderness; D014934:Wood
chemical_list: D002247:Carbon Isotopes; D012987:Soil