Fame, fate, and faunal extinctions
Date and Time
Saturday, March 7th, 2020
2050 Valley Life Sciences Building, UC Berkeley
9AM – 4PM
Hear from leading researchers on the diversity and disappearance of large land and marine mammals at the end of the last Ice Age. New methods of study are revealing patterns of extinction in the western US and throughout the Americas driven by rapid and significant ecological shifts over the last 100,000 years.
Sketch notes by Mark Simmons
8:15 - 9:00 AM
9:00 - 9:10AM
Welcome, logistics, and introduction
9:10 - 10:00
The Evolution and Extinction of a Marine Giant: Understanding the ecological traits of the Steller’s Sea Cow (Hydrodamalis gigas)
The Steller’s sea cow was an oddball among marine mammals. Not only was it the largest species (up to 9 m in length and estimated weight of 10 tons) within the order Sirenia (i.e., manatees and dugongs), the Steller’s sea cow was also a member of the only lineage of sirenians known to favor cold, marine waters. The aberrant traits of this species raise the question of whether living species of sirenians are actually suitable analogues for inferring the ecological preferences and habits of this extinct species. Using a suite of geochemical methods (Sr/Ca and Ba/Ca, bulk and compound specific C and N isotopes, structural carbonate C and O isotopes), I’ll highlight our latest understanding of the diet and habitat preferences of this species and explore how this relates to its evolution and extinction.
10:10 - 11:00
Ice Age Mammals of Alberta, Canada: A Story of Ancient Landscapes, Ice, and Extinction
In this presentation, I will discuss some of the studies my colleagues and I have undertaken to understand Ice Age mammals recovered from Alberta, and the environments in which these mammals lived. During the last glacial stage of the Pleistocene epoch, approximately 11,000 to 100, 000 years ago, the region that is now Alberta formed part of a passageway between eastern Beringia (Alaska and the Yukon) and unglaciated areas of the North American mid-continent. Mammal remains from this time period (including horses, bison, mammoths, and Jefferson’s ground sloth) provide information about how the landscape and ecosystems of this region changed. This information allows us to infer when the passageway became inaccessible as a result of the spread of continental ice sheets. Furthermore, the remains of some mammal species, particularly horses and mammoths, record information that is relevant to understanding their disappearance at the end of the Pleistocene.
11:10 - 12:00
Towards a more realistic model of late-Quaternary extinctions
At the end of the last Ice Age, the vast majority of earth’s large mammals became extinct during a time of extreme climate changes and rapidly increasing human populations. Despite decades of research, the relative contribution of these factors to the megafaunal extinction is still hotly debated. This talk will discuss new research on the South American continent that is elucidating how climate changes and human activities intersected to drive megafauna extirpations in different regions, and how these processes propagated across an entire continent, leading to the most recent and severe of the late-Quaternary extinctions. I will also discuss how asphaltic localities (“tar pits”) in the Neotropics as well as North America are helping scientists paint a clearer picture of Ice Age ecosystems and what led to their collapse.
12:10 - 1:15
Lunch break (on your own)
1:20 - 2:10
The Bay Area's Hidden Megamammal Past
The rocks of the San Francisco Bay Area preserve more than 15 million years of mammal history in sediments that are beneath our feet, our basements, and the wheels of our cars. Be introduced to sloths on BART, camels that ranged over Mt. Diablo, backyard whales, and mammoths from the Twin Peaks Tunnel that are tucked away in the collections of the UCMP. Learn how our understanding of the mammalian faunas of Northern California has grown as the Bay Area itself has expanded and the importance of California’s environmental laws in recovering and preserving our fossil history.
2:20 - 3:10
Cracking The Coldest Case - Ice Age extinctions in western North America
Everyone loves a good mystery, and the widespread extinction of large mammals at the end of the Pleistocene Epoch – the Ice Ages – is no exception. Attempts to explain the loss of North America’s mammoths, mastodons, sabre-toothed cats, and other megafauna are legion; these include climate change, overkill by humans, hyperdisease, and even an extraterrestrial impact, as well as some combination of some or all of these. Yet the clues to understanding what happened in North America as the Pleistocene waned may actually lie in the animals themselves – those that died out, and those that survived. This talk will review the current status of major extinction theories and scenarios as they pertain to late Pleistocene North America, evaluating strengths and weaknesses of each, and suggest future avenues of exploration for resolving this long-standing mystery.”
3:20 - 4:00
About the Speakers:
Mark Clementz is Professor and Head of the Department of Geology & Geophysics at the University of Wyoming. He has expertise in stable isotope and geochemical analysis of fossils and sediments for understanding the ecology of ancient life. His research has focused on the evolution and ecology of marine mammals (whales and sea cows) as they made the land-to-sea transition over 50 million years ago. Stable isotope evidence from this research has shown that the evolutionary ecology of these groups closely tracks changes in the physical and chemical properties of the seawater in which they live and, as with marine foraminifera, can provide information on paleoceanographic conditions through the Cenozoic Era.
Christina Barron-Ortiz is assistant curator of Quaternary Palaeontology at the Royal Alberta Museum. Her current research interests include studying the ecology, palaeobiology, and systematics of Quaternary ungulate mammals across the breadth of their North American range, from Mexico to the Canadian Arctic. She also has a major role in maintaining and developing the Quaternary Palaeontology Collection at the Royal Alberta Museum. Using cutting-edge techniques and methods, Christina is helping to unlock the wealth of information preserved in skeletal tissues of Ice Age fossils. Those data ultimately provide a more complete picture of Western Canada during the Ice Age.
Emily Lindsey is Assistant Curator and Excavation Site Director at the La Brea Tar Pits, a site that preserves millions of bones of late-Quaternary megafauna along with fossils of small vertebrates, invertebrates, and plants in asphaltic sediments. Her research focuses on understanding how Ice Age mammals and their ecosystems functioned, how climate change and human actions intersect to cause extinctions, and predicting how plants and animals will respond in the face of modern global change.
Patricia Holroyd is a Senior Museum Scientist for UCMP, where she has taken charge of the care and development of the vertebrate paleontology collections for the last 25 years. Her research focuses on understanding changes in mammalian and reptile communities through major periods of climate change.
Eric Scott is Principal Paleontologist for Cogstone Resource Management, Inc., a California-based consulting firm, as well as adjunct in the Department of Biology at California State University, San Bernardino, and emeritus Curator of Paleontology for the San Bernardino County Museum in Redlands, California. He studies the evolution and extinction of Pleistocene megafauna, particularly horses and bison, with a focus on systematics and biogeography through time.