Abstract - Paleoecology of the Early and Middle Archaic Section of the Beaver Creek Shelter (39CU779), Wind Cave National Park, Custer County, South Dakota
Benton, Rachael Carol. 1991. Paleoecology of the Early and Middle Archaic Section of the Beaver Creek Shelter (39CU779), Wind Cave National Park, Custer County, South Dakota. M.S. Thesis. South Dakota School of Mines and Technology. 307 p.
This study is based on a one meter thick section encompassing the Early and Middle Archaic time periods within the Beaver Creek Shelter, Wind Cave National Park. Radiocarbon dates indicate that the studied units range in age from 4010 ± 100 BP to 6720 ± 100 BP, which closely correlates with the Altithermal climatic period. Artifacts found with the four younger startigraphic layers (Unints 13,14,15, and 16) of the studied section provide evidence for human habitation at the site. The sedimentary deposits from the site document the existence of overbank deposits probably due to occasional flooding. These depositional events are very similar to those occurring in the Beaver Creek Valley today, and Beaver Creek may have flowed very close to the Shelter at one time. Although, vertebrate, plant and gastropod remains were found throughout the studied units, this study is based solely on the vertebrate materials. All of the vertebrate remains were disarticulated and many of the elements were broken. Specimens were brought into the site by human inhabitant, carnivores and by fluvial processes. Animals who were in search of food and cover were also attracted to the site. Based on a tabulation of minimum number of individuals, within 10 cm thick increments, Levels 11 and 12 indicate a rise in abundance of specimens without a corresponding increase in matrix. A small percentage of burned elements, comprising mostly mammals were primarily concentrated wihtin Levels 6 through 10. The majority of specimens within the studied section were from mature adults with few juveniles or older individuals signifying a rapid faunal accumulation. Overall, the vertebrates correlate closely with the extant fauna found in the Black Hills. As an ecological community, the taxa are most commonly associated with a meadow, woodland and grassland interface which presently occurs along Beaver Creek. Even though this change has not been shown to be statistically significant, it is important to note that a slight increase in taxa with a dry habitat preference occurs within the lower levels of the studied section. In addition, when the author compares the studied fauna elements of this study with those found in the Late and Post-Archaic units (Abbot, 1989), the number of taxa with a dry environmental preference increases with the older units. These taxa include: Perognathus sp. indet., Dipodomy sp. indet., Onychomys sp. indet., and a taxon within the family Iguanidae. The specimen numbers of Micrtous pennsylvanicus, which is commonly associated with moist meadow and riparian enviroments, also increase within the younger units. Because of the higher elevation of the site in relation to the surrounding plains and its close proximity to flowing water, the Beaver Creek Shelter could comply with the refuge hypothesis proposed by many earlier researchers. A noticable addition of taxa prefering a drier habitat, and the site's elevation provide evidence for a slight drying trend and the existence of a possible refuge for both humans and animals under climatic pressure.