New York State Museum scientists have completed research that reveals when and why large mammals — including caribou, mammoths, and mastodons — re-colonized and ultimately went extinct in New York State after the last Ice Age. This research may help scientists better understand how ecosystems formed and why certain species went extinct after the last Ice Age.
Dr. Robert Feranec, the Museum’s curator of Pleistocene vertebrate paleontology, and Dr. Andrew Kozlowski, the Museum’s glacial geologist, co-authored the research that appears in the most recent issue of the journal Quaternary Research (Volume 85, Issue 2).
At the height of the last Ice Age, approximately twenty-five thousand years ago, the area that is now New York State was nearly entirely covered in ice. As the earth moved from a glacial climate to an interglacial climate and the ice melted, new land was opened to colonization by plants and animals. By carbon dating specimens in the State Museum collections as well as analyzing carbon dates of caribou, mammoths, and mastodons from other published research, Feranec and Kozlowski were able to determine the colonization and extinction patterns of those species following the last Ice Age.
Based on the carbon dates, a pattern in the timing of colonization emerges with caribou appearing first, about 17,000 years ago. Mammoths followed shortly thereafter, arriving when their preferred habitat, a tundra environment, was present in the state. A few thousand years later, mastodons then colonized the state when their preferred habitat, boreal forest, became present.
Interestingly, the scientists found that the pattern of extinction was opposite that of colonization. At the end of the Pleistocene epoch, about 12,000 years ago, mastodons went extinct in the state first, followed by mammoths. There are historical records of caribou in the state up to and during the Colonial period (about 200 years ago).
Paleontologists have long debated the cause of the end-Pleistocene extinction when over 50 species of large mammals went extinct in North America. Different arguments have focused on whether the extinction was caused by human-related impacts, such as over-hunting animals, by climate change and subsequent habitat change associated with the shift from a glacial period to an interglacial period, or by a combination of the simultaneous impacts of humans and climate.
Based on this study, at the time of their extinction in the state, the preferred habitats of both mammoths and mastodons were still present; therefore implicating that lack of food or preferred habitat alone could not have been significant contributors to their demise. However, about 1,000 years before these species go extinct, humans enter the state. Feranec and Kozlowski determined that while humans may not have been the only cause in the extinction of mammoths and mastodons in New York, and elsewhere in North America, they likely played a role in the extinction of many species.
Feranec and Kozlowski note that these results not only provide clues to life in the past, but also help provide a basis for understanding more modern concerns, such as the effects of current climatic change on species today and how those species will respond. This study illustrates the need and value of collections-based research to address modern societal issues.
Drawing of caribou by Wikimedia user Foresman.