Paleoclimatic reconstruction of the Late Pleistocene Talara Tar Seeps, Peru, using fossil reptiles, small mammals, and birds

Abstract

Functional traits of vertebrates can be used to infer paleoenvironmental conditions, allowing research into past climate changes and biotic responses. Birds are generally considered poor palaeoclimatic proxies due to their high vagility. Here, we analyze biogeographical and climatic niche information from multiple vertebrate groups including small mammals, reptiles, and birds to infer the paleoclimatic conditions present during the Late Pleistocene (∼14,500–17,000 years BP) at Talara, an asphaltic paleontological locality on the northern Peruvian coast. We created Ecological Niche Models for the nearest living relative of each fossil species identified at Talara. We then used the Mutual Ecogeographic Range method, obtaining the overlapping area between distributions for each vertebrate group (birds, reptiles, and small mammals) as well as for combinations of groups, to infer the paleoclimate at Talara and to determinate what taxonomic groups are best for reconstructing climate in this system. Our analyses indicate that conditions at Talara were slightly cooler and significantly wetter than those of the present day. Individually, different vertebrate groups provide different paleoclimatic information. Birds were found to be a poor paleoclimatic proxy. Mammals were good for inferring paleoprecipitation but not paleotemperature. Reptiles were good group for inferring paleotemperature but not paleoprecipitation. While analyzing all vertebrate groups together yields the most robust conclusions, reptiles and small mammals combined are a good proxy for inferring both paleoprecipitation and paleotemperature. Our results suggest an interstadial period that agrees with paleotemperatures inferred from isotopic and sedimentary information. Our research indicates that today, the southern portion of the Cauca biogeographic province (230 km NE from Talara) has comparable climatic conditions to Late Pleistocene Talara. Understanding how the Talara region transitioned from this biodiverse ecosystem to the hyperarid coastal desert of today could have important implications for predicting biotic response and tipping points in the context of modern climate change.