No abstract

Understanding the resilience of early societies to climate change is an essential part of exploring the environmental sensitivity of human populations. There is significant interest in the role of abrupt climate events as a driver of early Holocene human activity, but there are very few well-dated records directly compared with local climate archives. Here, we present evidence from the internationally important Mesolithic site of Star Carr showing occupation during the early Holocene, which is directly compared with a high-resolution palaeoclimate record from neighbouring lake beds. We show that-once established-there was intensive human activity at the site for several hundred years when the community was subject to multiple, severe, abrupt climate events that impacted air temperatures, the landscape and the ecosystem of the region. However, these results show that occupation and activity at the site persisted regardless of the environmental stresses experienced by this society. The Star Carr population displayed a high level of resilience to climate change, suggesting that postglacial populations were not necessarily held hostage to the flickering switch of climate change. Instead, we show that local, intrinsic changes in the wetland environment were more significant in determining human activity than the large-scale abrupt early Holocene climate events.

ABSTRACT. An isotopic database for the Pacific/Polynesian rat (Rattus exulans) and foods that it scavenges is used to examine diet-induced 14C age variation in omnivores. We discuss a suite of 26 e14C determinations and 13C and 15N analysis for modern Pacific/Polynesian rat bone gelatin and available food items from Kapiti Island, New Zealand (40°51'S, 174°75'E). These analyses provide the first isotopic data for modern specimens of the species, collected as part of a larger project to determine potential sources of bias in unexpectedly old 14C age measurements on subfossil specimens of R. exulans from New Zealand. Stable C, N and 14C isotopic and trapping data are used to trace carbon intake via the diet of the rats in each habitat. Data from specimens linked to five specific habitats on the island indicate that modern populations of R. exulans are not in equilibrium with atmospheric values of O14C, being either enriched or depleted relative to the atmospheric curve in 1996/97, the period of collection. The e14C values recorded for R. exulans are associated with diet, and result from variation in e14C values found in animal-protein food items available to a scavenging omnivore. The titer of carbon deviating from atmospheric values is believed to be derived from the essential amino acids in the protein-rich foods of the rat diet.Present evidence suggests that the depletion required to affect 14C ages limits the possibility that diet introduces dramatic offsets from true ages. Marine diets, for example, would have a variable effect on ages for terrestrial omnivores, contraindicating the application of a standard marine correction for such specimens. We suggest that to identify the extent to which diet may influence the 14C age in a given specimen of terrestrial omnivore, the separation and dating of essential amino acids vs. a nonessential amino, such as glycine, be applied.

We inferred climate change through the Pleistocene-Holocene transition from δ 13 C and δD values of bat guano deposited from 14.5 to 6.5 ka (calendar ka) in Bat Cave, Grand Canyon, Arizona. The δ 13 C and δD values generally covaried, indicating that regional late Pleistocene climate was relatively cool and wet, and early Holocene climate gradually became warmer with increased summer precipitation until ca. 9 ka, at which time the onset of modern North American Monsoon-like conditions occurred. During the Younger Dryas event, δ 13 C values decreased, whereas δD values increased, indicating a cool and possibly drier period. We also observed a distinct isotopic anomaly during the 8.2 ka event, at which time both δ 13 C and δD values decreased. The δ 13 C values abruptly increased at 8.0 ka, suggesting a rapid change in atmospheric circulation and greater infl uence from convective storms originating from the south. Deposits of bat guano represent a largely untapped source of paleoenvironmental information that can provide continuous and long-term continental archives of environmental change.

Intentional dental modification, in the form of ablation and filing, is reported for the first time from Cambodia in two late prehistoric sites (Phum Snay and Phum Sophy, c. 2500 to 1500 bp). Bioarchaeological research is relatively new for this region, and this study significantly adds to our reconstruction of past behaviours in mainland Southeast Asia. The skeletal samples combine both excavated material and large looted collections in the form of ossuaries. People from Phum Sophy and Phum Snay had similar rates of anterior maxillary dental ablation, 60 and 47%, respectively, and 21.4 and 7.7%, respectively, in the mandible. Patterns of ablation most commonly involve the removal of the maxillary lateral incisors. Intentional filing was less common than ablation but affected Phum Snay and Phum Sophy individuals to a similar level (4–7%). Filing was also restricted to the anterior dentition, and a range of patterns were evident, many involving filing of the mesial and distal aspects of the crown of the upper and lower incisors and canines to give a pointed appearance. Patterns of ablation or filing were not strongly associated with a particular sex or age group. However, a limited number of ablation and filing patterns were exclusive to each site. The significance of this practice in relation to rites of passage, status, community and family relationships, and trauma is discussed. It is also shown that the modifications show distinct differences in prevalence and pattern, particularly that of filing, to nearby temporal neighbours in southern Cambodia and northeast Thailand, suggesting a unique cultural behaviour for this region. Copyright © 2011 John Wiley & Sons, Ltd.