Asynchronous onset of anthropogenic soil erosion in monsoonal China during the Holocene

Abstract

Understanding the timing, magnitude, and spatial distribution of anthropogenic impacts on soil erosion during the Holocene is essential for predicting future erosion rates and for the sustainable management of soil resources. However, the lack of regional-scale synthesis for China has hindered the exploration of the impacts of human activities on soil erosion on the millennial timescale. We synthesized 859 calibrated 14C dates from 87 lake sediment cores from monsoonal China (MC). The lake sites were divided into six regions, with the objective of studying soil erosion rates based on sediment mass accumulation rates (MARs) on the regional scale since 12 cal. ka BP. The results showed that the MARs were positively corelated with monsoon intensity in north-central China (NCC) during 12–2 cal. ka BP, and negatively correlated with vegetation cover, throughout the Holocene in MC and in the other five regions. This indicates that precipitation change was the dominant factor influencing soil erosion in NCC during 12–2 cal. ka BP, while the influence of vegetation cover dominated the level of soil erosion in the other five regions during the Holocene. There was a pronounced intensification of anthropogenic soil erosion at ∼2 cal. ka BP in MC, but elsewhere this intensification was asynchronous on the regional scale. Pronounced anthropogenic soil erosion occurred at ∼2 cal. ka BP in NCC and southern China (SC), and at ∼1 cal. ka BP in northeastern China (NEC) and southwestern China (SWC). No significant anthropogenic impacts on soil erosion, based on MARs, were observed in the middle and lower reaches of the Yangtze River Valley (MLYR) and in the central and eastern Tibetan Plateau (CETP), likely due to the diverse range of factors influencing terrestrial inputs to lakes, and the complex sedimentary environment in the MLYR and the low population density in the CETP. Overall, this spatio-temporal pattern of soil erosion is supported by the intensification of human activity documented by the evidence from archeological sites and historical records.