Autumn nitrogen enrichment destabilizes ecosystem biomass production in a semiarid grassland  

作　　者：Yuqiu Zhang Zhengru Ren Haining Lu Xu Chen Ruoxuan Liu Yunhai Zhang 

机构地区：[1]State Key Laboratory of Vegetation and Environmental Change,Institute of Botany,Chinese Academy of Sciences,Beijing 100093,China [2]University of Chinese Academy of Sciences,Yuquan Road,Beijing 100049,China

出　　处：《Fundamental Research》2023年第2期170-178,共9页自然科学基础研究（英文版）

基　　金：funded by the National Natural Science Foundation of China (32122055 and 32071603);the Strategic Priority Research Program of the Chinese Academy of Sciences (XDA26020101).

摘　　要：Nitrogen(N)deposition decreases the temporal stability of ecosystem aboveground biomass production(ecosystem stability).However,little is known about how the responses of ecosystem stability differ based on seasonal N enrichment.By adding N in autumn,winter,or growing season,from October 2014 to May 2020,in a temperate grassland in northern China,we found that only N addition in autumn resulted in a significantly positive correlation between ecosystem mean aboveground net primary productivity(ANPP)and its standard deviation and significantly reduced ecosystem stability.Autumn N-induced reduction in ecosystem stability was associated with the vanished negative effect of community-wide species asynchrony(asynchronous dynamics among populations to environmental perturbations)on the standard deviation of ecosystem ANPP in combination with the emerged positive effect of dominance(Simpson's dominance index that indicates the relative weight of dominant species in a community).Our findings indicate that autumn N addition might overestimate the negative effect of annual atmospheric N deposition on ecosystem stability,suggesting that to better evaluate the influence of N deposition in temperate grasslands,both field experiments and global modeling should consider not only the annual N load but also its seasonal dynamics.Moreover,further studies should pay more attention to the alteration in the ecosystem temporal deviations,which might be more sensitive to human-induced environmental changes.

关 键 词：Biomass production Community stability Inner Mongolia Seasonal nitrogen addition Species asynchrony STEPPE Variability 

分 类 号：S81[农业科学—畜牧学]