Late Holocene Logistical and Residential Settlement in Interior Santa Rosa Island, California: A Comparative Analysis of Four Rockshelter Sites
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Authors
Oster, Mary Catherine
Issue Date
2021
Type
Thesis
Language
Keywords
Interior , Northern Channel Islands , Rockshelter , Santa Rosa Island , Settlement Patterns
Alternative Title
Abstract
California’s northern Channel Islands (NCI) are recognized by archaeologists for the highly complex, maritime Indigenous cultures that inhabited the islands at the time of Spanish contact. On Santa Rosa Island (SRI), the second largest of the NCI, numerous coastal sites have been studied extensively with respect to the subsistence-settlement system, while the role of interior sites within those systems has received less attention. Throughout the late Holocene (3350 cal BP�" Present) interior settlement included small encampments, in many cases for logistical forays to the interior for terrestrial resources. This was particularly the case with sites occupied during the late Middle Period (1300 �" 800 BP) and Middle to Late Period Transition (MLT; 800 �" 650 BP), which coincided with a period of severe and persistent droughts interspersed with wetter and more mild periods (the Medieval Climatic Anomaly, MCA, 1150�"800 cal BP). In other cases, some small sites represent smaller residential bases, a pattern that becomes more prevalent after the time of Spanish contact (408 cal BP) when Indigenous populations had declined. In this thesis, I examine the faunal records from four interior rockshelter sites within the context of late Holocene settlement systems on SRI to investigate how environmental and cultural factors may have contributed to the choices people made regarding how and where to settle, specifically the severe droughts of the MCA and the social effects of Spanish contact. In this thesis, I test two primary hypotheses that were formulated from the perspective of the Diet Breadth and Central Place Foraging (CPF) models from Human Behavioral Ecology (HBE). To test each hypothesis, I use four lines of evidence: radiometric dating (radiocarbon), faunal analysis (primarily marine fauna), stable isotopic data from Mytilus californianus shell, and geospatial analysis (Euclidian distance and Hot Spot analysis). The first hypothesis is that during the late Middle Period and MLT, settlement was likely influenced by drought conditions of the MCA, in part reflecting seasonal, short-term occupation during dry periods. The second hypothesis is that after Spanish contact, interior settlement at rockshelters reflects a more substantial or permanent settlement system for small population groups. The results of faunal analysis revealed that differences in the diversity and density of the faunal assemblages distinguishes the sites from one another, with the late Middle Period/MLT sites having less diversity and density than the post-contact period sites. The late Middle Period/MLT sites are consistent with CPF while the post-contact period sites violate the expectations of the model, suggesting they are residential sites instead of special-purpose sites. The seasonality studies for the sites indicate that one of the sites pertaining to the late Middle Period/MLT was occupied during the summer drought months, while this pattern was not observed at post-contact period sites. Finally, the geospatial analysis suggests that the sites are more likely to be in “hot spots” of resilient water sources, as well as closer to water sources, than are randomized points. Understanding the purpose of settlement at these interior sites during the late Holocene is essential to a complete picture of how people made decisions regarding environmental and cultural events on SRI, which can be extended to understanding similar choices people face in Mediterranean environments generally.