Pollen evidence of early human activities in Erhai basin, Yunnan Province

Abstract： The evidence of human activities around Erhai Lake catchment was revealed by pollen records from a sediment core in the lake, northwest Yunnan Province. The chronologic sequence based on AMS 14C data made it possible for pollen results to compare with archaeological records and historical documents. The preliminary deforestation started from the selective clearance at about 5500 14C a BP, marked by the loss of vertically distributed montane forest and the expansion of second pine woodland across the catchment. The deforestation resulted in the increase of surface runoff and the enhanced erosion in the catchment. The increased herbs of pasture and crop suggested the primitive agriculture and stockbreeding in study region. With the limited human activity, as well as the suitable climatic condition, second pine forest expanded quickly, resulting in the weakened soil erosion around the basin. The strong forest clearance inferred from pollen occurred since 2160 14C a BP, paralleling to the first dense immigration of population, when Yeyu County was first set up around west coast of Erhai Lake, documented in historic record. The development of agriculture led to the steady enhancement of soil erosion from farming land, increasing the input of fine materials and nutrients to the lake. Moreover, the serious deforestation by human activity stressed the vulnerability in ecosystem of the landscape. The time of primary anthropologic impact recorded from pollen is earlier than that of the oldest archaeological record by 1500 a (14C year). 作 者： YANG Xiangdong    SHEN Ji    Richard T.Jones    WANG Sumin    Tong Guobang    ZHANG Zhenke   作者單位： YANG Xiangdong,SHEN Ji,WANG Sumin(Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China)

Richard T.Jones(Department of Geography, University of Exeter, Exeter EX4 4RJ, UK)

Tong Guobang(Institute of Hydrogeology and Engineering Geology, CAGS, Shijia- zhuang 050061, China)

ZHANG Zhenke(Department of Urban and Resource Sciences, Nanjing University, Nanjing 210093, China) 

期 刊： 科學(xué)通報(bào)（英文版）  SCI   Journal： CHINESE SCIENCE BULLETIN  年，卷(期)： 2005, 50(6)  分類號(hào)：   Keywords： pollen    vegetation    evidence of human activities    Erhai Lake   

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