Natural Trap Cave Revisited: Ancient DNA, Climate and the Megafaunal Extinction

Des Moines University, West Des Moines IA

Investigators

Abstract

Non-technical abstract The end of the ice age (about 11,000 years ago) was a time of radical change in North America. Many species of large mammals went extinct, along with their habitats. Climate played a major role in this extinction event and current climate change continues to affect and alter the world today. This project will analyze ancient DNA from ice age animals from Natural Trap Cave, Wyoming to examine how these past climate changes relate to genetic variability and extinction. This research will lead to a better overall understanding of how climate change is related to population structure, changes in genetic variation, and ultimately extinction, which may have potential effects on how biologists think about and mitigate the current human-caused climate change occurring today. This project will also provide many opportunities for scientific engagement and outreach to both the general public and in classroom settings. The intriguing nature of the excavations and ultimate findings make this expedition a perfect opportunity to bring science to the general public through print and television media. Additionally, this is an excellent opportunity to give high school students real time experience on how field science is performed. Via remote participation on the web, this project will give students the opportunity to participate in the experience of what it is like to excavate a fossil site, live out in the field, and unearth bones of gigantic, long-dead beasts, but in a safe, virtual setting. Technical abstract The end-Pleistocene was a time of radical change in North America. Many species of large mammals went extinct, along with the loss of a variety of associated ecosystems. Climate played a major role in this extinction event and current climate change continues to affect and alter ecosystems today. This project will re-open Natural Trap Cave in northern Wyoming to investigate paleoecological responses to climate change and how this relates to the megafaunal extinction events at the end of the Pleistocene. The permanently cold and moist conditions at NTC have preserved a large collection of megafaunal bones which still contain ancient DNA (aDNA) and collagen molecules. This rare resource is optimal to perform population-level analyses of genetic variation in the critical phases before, during, and after the end-Pleistocene extinction events. Key questions investigated in this project include: 1) Was the Pleistocene extinction event preceded by, or concurrent with a large loss of genetic diversity? 2) Are morphological changes at the Pleistocene/Holocene boundary the product of adaptation, or immigration? 3) Are major shifts in morphological and genetic variation correlated with climate change? Using aDNA, AMS radiocarbon dates, stable isotope analyses, morphological analyses, and previous data from NTC this project will investigate changes in climatic conditions and how they correlate with genetic diversity and morphological change. This research will lead to a better understanding of how climate change drives extinction and may reveal correlations between climate change, metapopulation structure and changes in genetic and morphological variation.