Environmental changes and human activity since the Neolithic: Evidence from pollen and phytoliths in Hochung, Sai Kung area, Hong Kong

An excavation has revealed in Hochung, in the Sai Kung area of Hong Kong, which mainly deposited during the Middle to Late Neolithic period. Base on pollen and phytolith analysis, and combine with pervious published report reconstructed the paleoenvironmental changes around the archeological site. Results show that the settings around the Hochung site changed from river bank, lagoon to floodplain marsh and finally changed to cultivated land during Middle to Late Holocene. Evidence of pollen and phytoliths, coupled with the excavated relics, revealed that the Neolithic culture was characterized by fishing and hunting at ~ 4200-3500 yr BP, without evidence of rice cultivation or other agricultural activity in this area. Until the Tang and Song Dynasties, rice cultivation appeared based on pollen and phytolith assemblages, but the area of excavated site was not yet an in situ rice field. During the Ming and Qing dynasties, rice agriculture flourished, and the area turned into a local paddy field, lasting until 1960s. Meanwhile, the gradual reduction of evergreen broad-leaved trees and the increase of pioneer plants such as Dicranopteris and other secondary plants since the Tang and Song dynasties imply that the expansion of human agricultural activity caused serious damage to the natural evergreen broad-leaved forest. In the history period, the agriculture civilization has very closely relationship between the south area and the north area, especially from the Qin Dynasty to present.