Soil water content and salinity critically regulate soil microbial composition,plant community structure,and ecosystem multifunctionality(EMF)in semi-arid grasslands.However,the mechanisms through which drought(D),sal...Soil water content and salinity critically regulate soil microbial composition,plant community structure,and ecosystem multifunctionality(EMF)in semi-arid grasslands.However,the mechanisms through which drought(D),saline-alkaline(SA),and their combined(DSA)stress influence these ecological components remain poorly understood.This study investigated these mechanisms along natural gradients in a semi-arid grassland of China by analyzing soil physical-chemical properties,microbial communities,and vegetation characteristics.The results showed that as the environmental stress shifted from the D group to the DSA group and then to the SA group,soil electrical conductivity significantly increased,while urease and phosphatase activities significantly decreased.Soil organic carbon,total nitrogen,total phosphorus,and microbial biomass carbon and nitrogen were lower in the D and SA groups than in the DSA group.Meanwhile,plant biomass showed an increasing trend along the treatment gradient,primarily driven by dominant species,while plant diversity did not exhibit significant differences.Further analysis identified the soil water content and salinity as the key determinants of soil microbial diversity and community complexity.Soil enzyme activities exhibited contrasting relationships with microbial composition,correlating positively with the richness of bacterial amplicon sequence variants(ASVs)but negatively with the richness of fungal ASVs.Notably,microbial biomass,which varied significantly across different groups,emerged as a key predictor of changes in EMF,with its critical role confirmed through structural equation modeling.These findings collectively elucidate the responses of ecological communities to synergistic soil hydro-saline stress in semi-arid ecosystems,while highlighting the critical role of microbial biomass in maintaining EMF.展开更多
The water of Bosten Lake was released to lower reaches of the Tarim River for 5 times from 2000 to 2002. The changes of total dissolved solid (TDS) and the major ions (SO2-4, Cl-, Na+, Ca2+, Mg2+ and HCO-3) were ana...The water of Bosten Lake was released to lower reaches of the Tarim River for 5 times from 2000 to 2002. The changes of total dissolved solid (TDS) and the major ions (SO2-4, Cl-, Na+, Ca2+, Mg2+ and HCO-3) were analyzed during this period. It was found out that TDS and the concentrations of the major ions initially and quickly increased and then decreased, but finally increased again. These changes were different at different distances from the river, which indicated that the groundwater changes relied on the distance from the river. In addition, the salt in groundwater was only diluted but not removed by the water. It was suggested that ecological measures should be sought to really promote the quality of the groundwater at the lower reaches of the Tarim River.展开更多
基金supported by the China Central Government-Guided Local Science and Technology Development Project(23ZYQA291)the Innovation Star Project for Excellent Postgraduates in Gansu Province(2025CXZX-169)the Key Science&Technology Project of Gansu Province,China(22ZD6NA007)。
文摘Soil water content and salinity critically regulate soil microbial composition,plant community structure,and ecosystem multifunctionality(EMF)in semi-arid grasslands.However,the mechanisms through which drought(D),saline-alkaline(SA),and their combined(DSA)stress influence these ecological components remain poorly understood.This study investigated these mechanisms along natural gradients in a semi-arid grassland of China by analyzing soil physical-chemical properties,microbial communities,and vegetation characteristics.The results showed that as the environmental stress shifted from the D group to the DSA group and then to the SA group,soil electrical conductivity significantly increased,while urease and phosphatase activities significantly decreased.Soil organic carbon,total nitrogen,total phosphorus,and microbial biomass carbon and nitrogen were lower in the D and SA groups than in the DSA group.Meanwhile,plant biomass showed an increasing trend along the treatment gradient,primarily driven by dominant species,while plant diversity did not exhibit significant differences.Further analysis identified the soil water content and salinity as the key determinants of soil microbial diversity and community complexity.Soil enzyme activities exhibited contrasting relationships with microbial composition,correlating positively with the richness of bacterial amplicon sequence variants(ASVs)but negatively with the richness of fungal ASVs.Notably,microbial biomass,which varied significantly across different groups,emerged as a key predictor of changes in EMF,with its critical role confirmed through structural equation modeling.These findings collectively elucidate the responses of ecological communities to synergistic soil hydro-saline stress in semi-arid ecosystems,while highlighting the critical role of microbial biomass in maintaining EMF.
基金National Natural Science Foundation of China No.90102007+1 种基金 Knowledge Innovation Project of Chinese Academy of Sciences No.KZCX1-08-03
文摘The water of Bosten Lake was released to lower reaches of the Tarim River for 5 times from 2000 to 2002. The changes of total dissolved solid (TDS) and the major ions (SO2-4, Cl-, Na+, Ca2+, Mg2+ and HCO-3) were analyzed during this period. It was found out that TDS and the concentrations of the major ions initially and quickly increased and then decreased, but finally increased again. These changes were different at different distances from the river, which indicated that the groundwater changes relied on the distance from the river. In addition, the salt in groundwater was only diluted but not removed by the water. It was suggested that ecological measures should be sought to really promote the quality of the groundwater at the lower reaches of the Tarim River.
