Paleoecology of Pleistocene megafauna in southern Nevada, Usa: Isotopic evidence for browsing on halophytic plants

Stable isotopic techniques are emergent as a powerful reconstructive tool in Neogene paleoecology. The Las Vegas Valley in southern Nevada contains one of few diverse Late Pleistocene fossil assemblages in the Mojave Desert. This study investigates the diet of four megafaunal genera (Mammuthus, Equus, Bison, and Camelops) using delta 13C signatures preserved in tooth enamel. Results from serial sampling are also presented as a subannual record of dietary variation and seasonality. During the Last Glacial Maximum, the three grazing genera (Mammuthus, Equus, and Bison) consumed C3 and C 4 grasses in the naturally occurring proportion, which consisted primarily of C3 grasses. Camelops delta13C values indicate the highest dietary proportion of C4 plants; I interpret that these animals consumed browse material with a high proportion of the halophytic C4 shrub Atriplex, a substantial component of modern Mojave Desert vegetation. This study provides new insight into stable isotopic applications for reconstruction of arid paleoenvironments.