Spatio-temporal distribution of hunter-gatherer archaeological sites in the Hokkaido region (northern Japan): An overview

The spatio-temporal distribution of archaeological sites in the Hokkaido region reveals hunter-gatherer population dynamics from the Upper Palaeolithic (>14,000 cal. yr BP) through the Neolithic/Jomon and Epi Jomom period (c. 14,000-1300 cal. yr BP) to the historic Ainu period (c. 700-100 cal. yr BP). It appears that most cultural transitions coincide with periods of climate and environmental change. However, this observation does not automatically mean causality and, therefore, other potential driving factors must be checked. The data support the hypothesis that Palaeolithic subsistence was (at least partly) based on terrestrial hunting. Paralleled by lateglacial climate amelioration, rising sea levels and a change in marine currents, this strategy shifted towards marine resources and plant exploitation at the beginning of the Jomon period. Along with continuous Holocene climate warming, Hokkaido's Neolithic Jomon population increased culminating in the Middle Jomon period (5000-4000 cal. yr BP). Simultaneously, Jomon subsistence underwent a process of diversification and intensification in exploitation of food resources. This practice probably allowed the persistence of the Middle Jomon culture beyond the Holocene temperature optimum (around 5000 cal. yr BP). Thereafter, the population decreased until the end of the Jomon culture accompanied by a trend towards cooler climate conditions and a shift in subsistence towards a more narrow range of food resources with increased hunting and less plant food. Population re-increased during the Satsumon/Okhotsk culture periods (1500-700 cal. yr BP), which may be the result of Okhotsk immigration because of climate cooling in the regions north of Hokkaido and enhanced inner-Hokkaido trade (between Satsumon and Okhotsk) and trade with communities outside Hokkaido. During the Ainu period (c. 700-100 cal. yr BP), site, and possibly population numbers, re-decreased significantly and concentrated in eastern Hokkaido. Whether social and/or climatic factors brought about the Satsumon-Ainu cultural transition and the observed change in population pattern remains unresolved.