Climate-driven soil erosion processes in alpine environments over the last century: Evidence from the Taibai Mountain (central China)

Abstract

Over the last century, climate warming has increased vegetation coverage in alpine regions, having major implications for associated terrestrial and aquatic ecosystems. Due to the remoteness of mountainous regions, there is a paucity of monitoring data regarding the response of catchment processes to climate change. Particle size distribution, magnetic properties, and elemental contents were investigated in 210Pb-dated sediment cores (34 cm in length) collected from two hydrologically-connected cirque lakes in the Taibai Mountain (the highest mountain in east mainland China). Both lakes have experienced directional environment changes since the 1980s, suggested by concurrent increases in magnetic susceptibility and organic matter. Prolonged growth season under a scenario of warmer climate has promoted vegetation development and soil conservation, subsequently increasing the contribution of terrestrial detritus derived from top soils that are rich in magnetic minerals and organic matter. Contents of clay and silt remained high throughout the two sediment cores, suggesting that depositional environment was relatively stable in both lakes. However, few peaks in coarse particles probably resulted from the cold and wet climate between the 1940s and the 1970s. During the relatively cold and wet episodes, prolonged snow-packs and enhanced melt-water discharge would strengthen bedrock weathering and erosion intensity, subsequently increasing the influxes of coarse particles. This is the first study to reveal decadal-scale changes in catchment processes of the Taibai Mountain, and the results highlight positive effects of climate warming on environmental protection of our study site and other similar alpine mountains through promoting water and soil conservation.