Assessing Pleistocene–Holocene climatic and environmental change in insular Near Oceania using stable isotope analysis of archaeological fauna

In comparison to temperate and arid regions, environmental responses to the Last Glacial Maximum and the Terminal Pleistocene and Holocene boundary remain poorly known for many parts of the tropics, making it challenging to unravel human–landscape interactions across this timeframe. This is particularly the case in insular Near Oceania, where sea-level fluctuations and potential changes in forest cover may have had major impacts on hunter–gatherer populations. Here, we apply stable carbon and oxygen isotope analyses to small-mammal teeth from four Pleistocene–Holocene (spanning from 29 000 years ago to the late Holocene) sequences in the Bismarck Archipelago to reconstruct changes in environments directly exploited by human populations in this part of the world. Our results show a subtle response of tropical habitats in Near Oceania to relatively arid conditions during the late-glacial period, something that has also been observed at sites in South and Southeast Asia, followed by a Terminal Pleistocene–Holocene expansion of tropical forest cover. Nevertheless, site-based variability in environmental responses across this period highlight the need for more multidisciplinary studies of human occupation sequences in a region that is becoming increasingly central to exploring human adaptations, environmental modifications and social network development over the past 20 000 years.