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Detecting riparian habitat preferences in “savanna” chimpanzees and associated Fauna with strontium isotope ratios: Implications for reconstructing habitat use by the chimpanzee‐human last common ancestor
Author(s) -
Hamilton Marian,
Nelson Sherry V.,
Fernandez Diego P.,
Hunt Kevin D.
Publication year - 2019
Publication title -
american journal of physical anthropology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.146
H-Index - 119
eISSN - 1096-8644
pISSN - 0002-9483
DOI - 10.1002/ajpa.23932
Subject(s) - habitat , ecology , gallery forest , grassland , riparian zone , isotopes of strontium , fauna , geography , strontium , biology , physics , nuclear physics
Objectives Riparian or gallery forests are critical habitats for numerous plants and animals today. Paleoanthropologically, reliance on such habitats informs behavioral and ecological reconstructions; for example, gallery forest habitats likely played a critical role in the transition from ape to hominin in the early Pliocene and may represent a preferred habitat for the last common ancestor of chimpanzees and humans. Direct indicators for gallery forest habitats preference are lacking. The objective of this article is to assess whether strontium isotope ratios are a reliable indicator of habitat preference for fauna living in and around gallery forests. Materials and methods We report bioavailable strontium isotope ratios from the Mugiri River, its tributaries, and its gallery forest (Toro‐Semliki Wildlife Reserve, southwestern Uganda), and compare them to surrounding savanna‐grassland values. We compare these environmental values to strontium isotopes ratios in faunal tooth enamel to determine if habitat preferences are accurately reflected. Results Gallery forest and savanna‐grassland vegetations have significantly different strontium isotope ratio profiles. We trace these isotopic differences to the influence of the Mugiri tributaries, which originate on Paleoproterozoic gneiss deposits on top of the surrounding escarpments. These isotopic differences in vegetation are mirrored in the tissues of fauna with habitat preferences for either the gallery forest or the surrounding grasslands. Discussion This research demonstrates the potential of strontium isotope ratios to identify habitat preferences in modern or fossil fauna under proper geologic variability. It provides a methodological model for future studies seeking to reconstruct habitat preferences in early hominins.