This dissertation project, by Co PI Joshua Reuther, focuses on three study areas in the middle Tanana Valley (mTV) to provide records of local terrestrial ecological contexts and environmental changes in lowland settings that date to the Late Glacial and early Holocene (16,000 to 6,000 years ago) in interior Alaska and Eastern Beringia (Alaska and unglaciated portions of the Northwest Territories and Yukon, Canada). The archaeological record of the mTV provides a rich history of hunter-gatherer land use dating over 14,000 years old, and includes several important archaeological sites such as the Upward Sun River Site, and the Broken Mammoth, Mead, Swan Point sites located in the Shaw Creek Flats area (Holmes 2011; Potter 2005; Potter et al. 2011; Yesner 2007). These studies also established that a rich diversity of faunal communities inhabited this region during the Late Glacial and early Holocene periods; some of which are extinct or do not coexist in the region today. It has been suggested that the mTV was an ecological refugium for late Pleistocene megafaunal species, such as mammoth and bison, as their habitats from the prior glacial period began to fragment during climatic amelioration (Guthrie 2006; Yesner 2007). This project is part of two larger projects focused on prehistoric human ecology and foraging behavior in Eastern Beringia: the Quartz Lake-Shaw Creek Flats Multidisciplinary and Upward Sun River Site Projects.

The study areas are spread out across a 4,000 km2 area in the mTV and contain the presence of archaeological sites that have records of well-developed stratification of sediments and soils and preserved macrofossils. Two of the study areas are dune fields: the Little Delta Dunes (including the Upward Sun River Site) and Rosa-Keystone Dunes Fields (in the area of the Shaw Creek Flats); the third area is Quartz Lake, one of the largest lakes within the region. As a whole the study areas provide important information to understand the evolution of regional landscapes, paleoecological systems, and paleoenvironmental conditions dating back to 25,000 years ago, over 10,000 years prior to the currently accepted earliest human occupation of the region.

Late Glacial and early Holocene landscapes of the mTV were ones of moderate stability and landscape disturbance with high rates of wind-blown (aeolian) sand and silt (loess) deposition, and the presence of early-to-middle successional vegetation communities (herbs and forbs, shrubs, and deciduous trees) that fostered the presence of diverse mammal communities that no longer coexist in the region. Loess deposition and sand dune activity during theses periods were crucial to maintaining early-to-middle successional vegetation communities throughout much of the mTV lowlands. The dynamic cycle of aeolian activity and weak soil development in the Late Glacial and early Holocene fostered positive feedbacks between cyclical disturbances and human and non-human systems (plants and animals). Fires also played a prominent role, at least in the Shaw Creek Flats and Rosa-Creek Dunes Field, in reactivating dunes. A cycle of fires, aeolian sand deposition, vegetative regrowth of shrubs and trees, weak soil development, and, again, fires occurred for over 2,000 years in the Shaw Creek Flats during this period.

Mammal and bird communities were more diverse in the mTV lowlands during these cycles of vegetation-fire-aeolian aggradation-fire during the Late Glacial and early Holocene, in contrast to those of the middle Holocene (~6000 years ago). Late Glacial and early Holocene human populations were likely attracted to the mTV region because of the maintenance of higher mammal and bird biodiversity that was fostered by the presence of aeolian activity and natural fires which played a key role in maintaining early-to-middle successional vegetative communities throughout the L...

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