Middle to late Holocene changes in climate, hydrology, vegetation and culture on the Hangjiahu Plain, southeast China

Climate evolution and hydrological conditions have been crucial factors for cultural development on the east coast of China. The Hangjiahu Plain, given its unique geographic and bioclimatic location, and plentiful Neolithic sites, is an ideal area in which to examine the relationship between environmental change and cultural development along the Lower Yangtze River. We report high-resolution pollen, algae, spore, charcoal, total organic carbon and grain size data from core BHQ2, collected from the Beihu Wetland on the Hangjiahu Plain. The record spans the period from 6300 to 400 cal yr BP. We infer that the climate shifted from warm and wet during the middle Holocene to dry in the late Holocene. Warm and stable hydrological conditions in the Beihu Wetland area during the intervals 6300-6000 and 5300-4250 cal yr BP were optimal for the development of the Majiabang and Liangzhu Cultures. Turbulent, brackish-water conditions in the Beihu Wetland area from 6000 to 5300 cal yr BP, however, led people of the Songze Culture to abandon the area. Collapse of the Neolithic culture and abandonment of the site at Liangzhu City could have been linked to climate drying in the interval 4250-3500 cal yr BP. Dry climate and the turbulent, saltwater environment that prevailed from 3800 to 3600 cal yr BP made conditions difficult for the Maqiao Culture. After 3600 cal yr BP, brackish water gradually receded and local rice agriculture expanded. Persistent warfare during the Warring States Period and the Qin-Han Dynasties may have been a response to colder climate from 2300 to 2000 cal yr BP. The decrease in monsoon precipitation in the Hangjiahu Plain region was influenced by summer solar radiation during the middle to late Holocene.