Anthropogenic Influences on Soil Erosion since the Late Holocene and Contrasting Regional Sustainability in China

Abstract

A multi-disciplinary investigation of loess sections in the southeast and northwest of the Chinese Loess Plateau (CLP) and a sediment core drilled in Zhejiang Province of southeast China was conducted. Discrepancies among grain size distribution, rock magnetic properties, geochemical characteristics and chroma features, and up-section weakening relation between various proxies in the Sanmenxia loess section were f ound. The results were compared with those of the Bai-caoyuan loess section in the northwest of the CLP and the sediment records across the plateau and elsewhere. It was suggested that human impacts began to increase soil erosion on the CLP since the middle Holocene. In addition to the increased soil erosion being decoupled from drying climate after 4 ka, renewed intensification of soil erosion was suggested to occur within the interval of 1.5–2.5 ka as a result of enhanced human activities. The two detected increases in hu-man-induced soil erosion on the CLP are consistent with the human-driven land use changes or human–land interactions at national or regional scales, including the anthropogenic influences on the changes in the sediment load of the Yellow River. In contrast, no human impacts overwhelm-ing hydroclimate control of soil erosion was revealed in the Beihuqiao cores, Zhejiang. The population growth during the past 2400 years showed a relative decreasing trend on CLP and a relative increasing trend in Zhejiang. It is indicated that anthropogenic factors have played a key role in modulating the Earth’s surface environment. In particular, ecologically fragile areas, such as the CLP, would be much more susceptible to human disturbance and climate change. The current serious land degradation on the CLP mainly results from the negative feedback between hu-man–land interactions. Regional heterogeneity should be taken into account for sustainable de-velopment.