Isotopic paleoecology (δ13C, δ18O) of a late Pleistocene vertebrate community from the Brazilian Intertropical Region

Abstract

Isotopes are one of the best tools to reconstruct the paleoecology of extinct taxa, allowing us to evaluate their diet (through carbon; C3 and C4 plants), their niche breadth (BA) and the environment in which they lived. In the present work we go deeper in the use of isotopes, and explore a mathematical mixing model with the stable isotopic composition of one (carbon) and two elements (carbon and oxygen) to evaluate (i) the relative contributions of three types of food resources (leaves, fruits and C4 grass) for meso- and megaherbivores (body mass > 100 kg) that lived during the late Pleistocene in Sergipe, Brasil, and (ii) which of these herbivores (together with some faunivorous taxa) could be potential preys for Smilodon populator and Caiman latirostris. Finally, we reconstructed the paleoenvironment in which the vertebrate community of Sergipe lived and concluded that the environment of Sergipe was a closer and drier landscape than African savannah nowadays, at least between 27 ka to 11 ka. Keywords: Quaternary, mammals, paleoecology, South America, stable isotopes. Isotopos sao uma das melhores ferramentas para reconstruir a Paleoecologia de taxons extintos, permitindo sugerir dieta (por meio do carbono, plantas C3 e C4), o nicho ecologico (BA) e ambiente em que viveram. No presente artigo nos aprofundamos no uso dos isotopos, e exploramos um modelo matematico misto com um isotopo (carbono) e dois isotopos (carbono e oxigenio) (i) para sugerir tres recursos tipos de recursos alimentares (folhas, frutas e gramineas C4) para meso-megaherbivoros (massa corporal acima de 100 kg) que viveram no Pleistoceno final de Sergipe, Brasil, e (ii) qual desses herbivoros (juntamente com faunivoros) foram presas potenciais de Smilodon populator e Caiman latirostris. Por fim, reconstruimos o paleoambiente na qual a comunidade de vertebrados de Sergipe viveu, concluindo que eramais fechada e seca do que as savanas da Africa atualmente, pelo menos entre 27 mil a 11 mil anos atras. Palavras-chave: Quaternario, paleoecologia, America do Sul, isotopos estaveis.