Above- and below-ground response to soil moisture change on an alpine wetland ecosystem in the Qinghai-Tibetan Plateau, China

Abstract. Climate change is expected to affect plant communities worldwide. However, less is known about the consequences of global warming-induced decrease of soil moisture on alpine wetland ecosystem in the Qinghai-Tibetan Plateau. To determine response of natural alpine wetland community to decrease of soil moisture, we did a gradient analysis of soil moisture by sequence space-series variation. We used sequence space-series variation of soil moisture to reflect potential time-series variation of soil moisture in alpine wetland community, by examining the effects of spatial heterogeneity of soil moisture on wetland community, as well as by determining how shifts in above- and below-ground properties of alpine wetland community. We found that vegetation aboveground biomass, cover and height all significantly increased with increase of soil moisture, but species richness was decreased. Soil organic carbon, total nitrogen, available nitrogen, total phosphorus and available phosphorus all significantly increased with increase of soil moisture, but soil pH value, total potassium and available potassium were significantly decreased. Meanwhile, species richness showed significantly positive correlations to aboveground biomass, covers and height. Aboveground biomass, vegetation covers and height were all significant positively related to soil organic carbon, total N, P, and available N, P, but negatively related to total K. But, species richness were significant negatively related to soil organic carbon, total N, P, and available N, P, but positively related to total K. Our observation indicates that decreasing of soil moisture may potentially negatively impact on the above- and below-ground properties in alpine wetland community.