Ecological Approach to the Prehistoric Man and Environment around the Lower Basin of the Abukuma River

Abstract

The study of man-land relationships in prehistory requires good understandings of many aspects of the geographic environment of the past. Such an environmental reconstruction would be contributed by the geomorphological and palynological methods. This study aims to elucidate the history of man-land relationships in Neolithic period around the lower basin of the Abukuma River with these methods.
Around the lower basin of the Abukuma, many shell mounds of Jômon age have been excavated. At the high sealevel period (B. P. 6, 000-5, 500yr.), the shoreline seems to have been retreated judging from the locations of these shell mounds. But the rate of submergence differed region to region with the local geomorphic elements. Regional differentiation of basic economic pattern of these shell mounds' people was mainly determined by micro-geomorphologic element around settlement site. After this high sealevel period, the sea gradually regressed. The micro-geomorphic environment around shell mounds changed from marine to lagoonal. Following such environmental change, the staple food of shell mounds' people changed from Meretrix lusoria to Corbicura japonica.
The predominant vegetation of early Jômon age was deciduous broad leaved trees, especially Quercus and Ulmus. The climate of this period was warmer than present. In the broad leaved forest, Sus scrofa leucomystax, Cervus nippon nippon lived and these animals supplied important food resource for the specialized hunting people. On the other hand, prehistoric man gathered fruits and roots of plant in the forest. These impact of the prehistoric man destroyed the natural vegetation around settlement site. In the latter half of latest Jômon age (B. P. 2, 500yr.), the climate became cooler and wetter. At this period the predominant vegetation was Fagus and Cryptomeria. The author also studied animal ecology in relation to the change of vegetation and clarified the change of regional food resource of the prehistoric Man.