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 Grant Zazula, PhD Yukon Palaeontologist
My research is interdisciplinary in nature with the goal of reconstructing Ice Age environments in Beringia through the analysis of fossil plant remains, mammal bones, insects, and soils. Although I am new to the position of Yukon Palaeontologist, I am well acquainted with Beringian research. Since 1999 I have conducted various types of research in Yukon that link palaeontology with geology, archaeology and palaeoecology. My first project in Yukon was an Ice Age palaeobotanical (fossil plants) study on the Bluefish River that provides an environmental context to the incredible palaeontological and archaeological record at the near-by Bluefish Caves site. Work on the Bluefish River planted the seed for my diverse research interests and excitement for Beringian research that would eventually lead me to this position in Whitehorse. The research was published as “Full-glacial Macrofossils, Palaeoecology and Stratigraphy of the For the last four years, my research has been focused on Pleistocene arctic ground squirrels (Spermophilus parryii) in the Klondike goldfields. A great example of these fascinating rodents can be seen at the Yukon Beringia Interpretive Centre. I analyzed a few hundred nests with seed caches (or middens) that were recovered from frozen sediments exposed during placer gold mining. These middens are primarily composed of grassy nests built by male arctic ground squirrels for winter hibernation and seed and fruits cached for consumption upon spring emergence. Importantly, the middens contain an unprecedented wealth of fossil plant remains that tell us about the diverse steppe-tundra vegetation and ecosystems utilized by arctic ground squirrels during the Pleistocene. By radiocarbon dating several of these middens and collecting them in association with volcanic ashes (tephra) of known age, we determined they are associated with the initial phases of the last two major glacial intervals: ~25,000 years ago (onset of the last glacial maximum), and ~90,000 (the onset the previous glacial period). The middens also contain diverse faunal remains, including bones, droppings, and hair. Some of the bones suggest that arctic ground squirrels were preying upon smaller microtine rodents, such as mice, lemmings and voles. In addition to providing information on ancient ecosystems, these middens enable us to further understand the behavioral adaptations of arctic ground squirrels to Pleistocene conditions and how they have responded to climate change in the past. In many ways, arctic ground squirrels are ideally adapted to the open steppe environment of the last glacial maximum, yet they were readily able to respond to post-glacial environmental change which saw the demise of Beringia and establishment of the present boreal forest and tundra. The integration of both plant and animal palaeontological information is key to understanding how various ecological components interacted in Beringia and will continue to be a central theme of my research as the Yukon Palaeontologist. Beringia is a huge, complex place and uncovering its mysteries could never be done alone. As such, an important part of my research is collaborating and interacting with a variety of other Beringian scientists, from Yukon and abroad, including geologists, geneticists, ecologists, entomologists (insects), and climatologists. We all work together to integrate various types of scientific information and try to paint a big-picture of what Beringia was like during the Pleistocene. Working in a research team is fun and rewarding because we each bring our individual expertise together to help unravel large research questions. During the summer, my fellow researchers embark on fieldwork adventures that take us to many interesting places in Yukon Territory. One area that we have focused on is the Klondike goldfields near Dawson City. The Klondike has been one of Canada’s most prolific producers of Ice Age fossils for the last 100 years or so. Here, we have worked closely with the placer gold mining community who have assisted with many important discoveries and provide us with much information on the fossils. Most of these fossils consist of bones from the Beringian “big three” megafauna, bison (Bison priscus), horse (Equus) and woolly mammoth (Mammuthus). However, sometimes mummified remains of partial carcasses or limbs and other soft tissues are recovered too, including the famous horse (Equus lambei) mummy recovered at Last Chance Creek that dates to about 26,000 years ago. Mummified remains are especially important since they can tell us unique information that cannot be determined from bones alone, including the color of the animal’s hair or its last meal if the stomach contents are recovered. Another exciting discovery that I made in the Klondike in summer of 2004 is an in-tact, fossil grass-vegetated surface buried beneath the Dawson tephra around 25,300 years ago. The exceptional fossil preservation in the Klondike is owed to the fact that they are recovered from sediments that have been frozen for hundreds of thousands of years. In this sense, many fossil remains from the Klondike appear as if they were just taken out of a deep-freeze for scientists to study. The second area of great interest to our research team for Ice Age fossils is the Old Crow region. For many years palaeontologists such as Dick Harington have collected fossils that were eroded from the high river banks and deposited on gravel point bars at numerous spots on the rivers. Some of these gravel bars literally contain thousands of bones from a wide variety of Pleistocene animals. During the summer of 2006, I had the pleasure of participating in fossil collection at several localities in the Old Crow Basin. This was the first systematic palaeontological survey of the Old Crow River for many years. In less than one week of canoeing down the river we collected over 2000 fossil bones, most of which belong to Ice Age woolly mammoth and horse. However, some specimens belong to mammals that are much rarer in Pleistocene fossil assemblages, including giant beaver (Castor ohioensis), broad-fronted moose (Alces latifrons), western camel (Camelops hesternus), american mastodon (Mammut americanum), scimitar cat (Homotherium serum) and short-faced bear (Arctodus simus). I plan to radiocarbon date several specimens recovered from this survey to get a better idea of when particular animals were present in the Old Crow region. In addition to the mammal fossils, several bags of sediment from the bluffs were sieved to retrieve plant and insect fossils to provide an environmental context for the mammals. Radiocarbon dates from a variety of tundra, steppe and forest plant fossils suggest that large lakes periodically formed in the Old Crow Basin between ~40,000 and 15,000 years ago. An interesting aspect of the Old Crow region are the prospects for very old fossils, possibly dating beyond 3 million years ago during the Pliocene and Miocene Epochs that immediately proceeded the onset of the Ice Age. I hope to continue the long tradition of paleontological research in the Old Crow Basin in collaboration with the Vuntut Gw’itchin people by conducting regular palaeontological surveys on the Old Crow and Porcupine Rivers and helping to train future Beringian scientists in the community. I am excited to start my new position as Yukon Palaeontologist and look forward to many more years of interesting fossil discoveries will help fill in the details about the fascinating Ice Age world of Beringia.
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