Abstract
OBJECTIVES: In the San Francisco Bay Area, Late Holocene resource intensification models predict an increase in diet breadth and a reduction in foraging efficiency associated with an increase in population, sedentism, and territoriality among fisher-hunter-gatherer populations. Here we compare bone stable carbon (δ(13)C) and nitrogen (δ(15)N) isotope values of sites along the eastern bay shore to interpret how ecogeographical partitioning of resources by latitude and distance from the bay reflects differential access and control of resources. MATERIALS AND METHODS: With the support of, and in collaboration with, the Muwekma Ohlone Tribe of the San Francisco Bay Area, we analyzed bone collagen and bioapatite from 154 burials from Mánni Muwékma Kúksú Hóowok Yatiš Túnnešte-tka (CA-ALA-329) (2500-180 cal B.P.) to examine temporal changes in diet. Further, we examined the ecogeographical partitioning of resources in relation to published data from four contemporaneous sites. RESULTS: For collagen (n = 146), δ(13)C values average -18.2‰±0.7‰ (1SD) and δ(15)N values average 9.8‰±1.5‰ (1SD). For bioapatite (n = 144), δ(13)C values average -13.8‰±1.0‰ (1SD). Adult males had statistically significantly higher isotope values compared to adult females, but differences were minimal (< 1.1‰). No meaningful temporal changes in diet were identified. Regional dietary differences occurred along a latitudinal gradient of the eastern bay shore. DISCUSSION: Foraging efficiency was localized, suggesting that the exploitation of different microhabitats was critical to each tribal group. Stable isotope data complement zooarchaeological and paleobotanical data; although they reveal different aspects of subsistence practices and diet.