Late-Holocene vegetation change reveals the environment of ancient people and the origin of Huashan cliff paintings in Guangxi, southwestern China

摘要

Human activities in the historical period were determined by the natural environment and social characteristics. The Zuojiang Huashan Rock Art Cultural Landscape in Guangxi is the most important World Heritage for prehistorical culture in southwestern China. However, knowledge about the natural environment and associated historic human-climate interactions during the period of cliff painting creation remains scarce, which has been an obstacle to understanding the process of regional civilization. Here, we report a pollen record from the core distributing region of Huashan cliff paintings to interpret the natural environment and climate changes, and further to discuss how and why ancient people create these giant cliff paintings based on the relationships of human-climate interactions. Pollen results imply an existence of a mixed broad-leaf and conifer forest in the woodland landscape at Huashan region before 1860 cal. yr BP, after which pine forests were more prevalent. During the cliff painting period from 2370 to 2115 cal. yr BP, broad-leaf and conifer trees dominated the tree layer and provided the key source materials for painting. It can be reasonably assumed that people used stake or ladder to climb the cliffs and created the cliff paintings during a humid climate condition from 2560 to 2000 cal. yr BP. Furthermore, the humid climate during 2700 and 2400 cal. yr BP had been interrupted by short-term drought episodes. These turbulent climate episodes probably played the role of disasters and impacted on the human activities, leading to the social-political tensions and the out-break of war. During the Qin and Han Dynasties, social-political changes relieved the pressure from natural climate changes and led to a more stable society, in which the creating of cliff paintings was gradually fading. Our results manifest the necessity to analyze the natural environment and social-political background in combination in this study on ancient human activities.