Pollen Analysis of Caribou Dung from Ice Patches in Southwest Yukon: Ancient Caribou Ecology and Implications for Precontact Human Land-Use

Abstract

The purpose of this research is to better understand the relationship between ancient caribou ecology and precontact human land-use patterns in the southwest Yukon. In the summer, caribou are known to move to the alpine to seek high quality forage and use ice patches for relief from heat and insects. The selection of ice patches results in the aggregation of caribou at certain locales on the landscape which has important implications for precontact hunters in the region. To better understand ancient caribou ecology in the southwest Yukon, pollen was analysed from well preserved fossil caribou (Rangifer tarandus) dung from the Granger Mountain (JdUu-17) and Friday Creek (JcUu-1) ice patches. This paper provides a general overview of the pollen analysis of 51 samples of caribou dung collected from stratigraphic layers at ice patches. Radiocarbon samples collected from stratigraphically controlled layers of caribou dung at these sites provide dates ranging from 7460±40 to 460±40 years BP. Samples were comprised of a variety of wind- pollinated taxa such Picea, Pinus, Alnus, and Betula and insect-pollinated taxa such as Polemonium, Pedicularis and Epilobium. It is suggested that some of the pollen content of ancient dung from ice patches reflects plants selected by caribou during alpine “green-up” in warm summer months. Several pollen sources are considered in this discussion and further work on evaluating taphonomic processes will assist in interpreting pollen from fossil caribou dung.