TROPICAL ECOSYSTEM RESPONSE TO LATE-QUATERNARY ENVIRONMENTAL CHANGE: INSIGHT FROM REMARKABLE ASPHALT-PRESERVED BIOTAS

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At the end of the last Ice Age, about 12,000 years ago, most of the big animals on Earth went extinct and many ecosystems changed drastically. Scientists still don’t know why these changes happened because the fossil record is incomplete, preserving just brief snapshots in time. An exception are “tar pits,” paleontological sites where asphalt (a type of crude oil) seeped to the surface over thousands of years, preserving fossil remains of whole ecosystems including bones, wood, and insects. In this project, scientists and college students from Los Angeles and Peru will work together to excavate and study fossils from a Peruvian tar pit, reconstructing the biodiverse Ice Age ecosystem and investigating how it changed into the barren desert it is today. This ecosystem collapse occurred during a time of climate changes and human impacts similar to those happening now. It is hoped that studying these past changes can help prevent future extinctions. This project will engage North- and South American students and scientists in recovering, identifying, and describing fossil material from a north-coastal Peruvian asphaltic locality (colloquially, “tar pit”). The curated flora and fauna, comprising plant, small vertebrate, and invertebrate remains, will form a comprehensive and scientifically valuable late-Quaternary fossil collection in this poorly-studied region, and will be analyzed to investigate interactions between humans, climate, and biotic communities. This research will focus on three main questions: (1) What was the late-Quaternary ecosystem structure in the coastal western Neotropics, before the disappearance of the Pleistocene large mammal communities?; (2) How, when, and in response to what climatic and anthropogenic processes did this ecosystem undergo the dramatic ecological state change to its current desertified condition?; and, (3) How did these processes integrate with environmental changes and anthropogenic impacts in other South American regions, leading to a continental – and global – extinction event?This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.