Differences in respiration components and their dominant regulating factors across three alpine grasslands on the Qinghai−Tibet Plateau  

作　　者：Ya-Li LIU Jun-Feng WANG Guan-Li JIANG Lu-Yang WANG Zi-Teng FU Ho-Jeong KANG Qing-Bai WU 

机构地区：[1]State Key Laboratory of Frozen Soil Engineering,Northwest Institute of Eco-Environment and Resources,Chinese Academy of Sciences,Lanzhou 730000,China [2]University of Chinese Academy of Sciences,Beijing 100049,China [3]Beiluhe Observation and Research Station of Frozen Soil Engineering and Environment,State Key Laboratory of Frozen Soil Engineering,Northwest Institute of Eco-Environmental and Resources,Chinese Academy of Sciences,Lanzhou 730000,China [4]School of Civil and Environmental Engineering,Yonsei University,Seoul 03722,South Korea

出　　处：《Advances in Climate Change Research》2023年第3期437-448,共12页气候变化研究进展（英文版）

基　　金：This study was supported by the National Natural Science Foundation of China(41771080);It is grateful to the Beiluhe Frozen Soil Observation and Research Station(CAS)for providing the research site and assisting with field sampling and soil CO_(2)flux measurement.We gratefully thank the reviewers for their comments.

摘　　要：Greenhouse gases(GHGs)emissions from high-cold terrestrial ecosystems underlain by permafrost on the Qinghai–Tibet Plateau(QTP)have received widespread attention.However,the dominant factors regulating ecosystem respiration(Re)and its components(soil respiration Rs and heterotrophic respiration Rh)and how the differences in carbon emissions from different ecotypes and seasons remain are still unclear.We conducted a 2-year field investigation(August 2018 to October 2020)and applied the structural equation model(SEM)to clarify the changes in the factors controlling the respiration components during different seasons.The results indicate that the R_(e)and its controlling factors in three alpine grassland ecosystems(alpine steppe,alpine meadow,and swamp meadow)vary with seasons.Furthermore,autotrophic respiration(Ra)contributes the most to the seasonal changes in R_(e).The R_(e)gradually increases in the early growing season and rapidly decreases in the late growing season.Rh remains relatively stable during the year.Under these seasonal variations in the respiration components,the dominant factors controlling R_(e)in the nongrowing season are the temperature of the atmosphere–soil interface(heat flux,atmospheric temperature,and soil temperature at 5 cm depth)and microbial activity(microbial carbon and pH)with the variable importance projections>1.5.During the growing season,the dominant factors regulating R_(e),Rs,and Rh are the soil temperature with a standardized direct effect(SDE)of 0.424,soil nutrient conditions(total nitrogen and pH)with SDEs of 0.570–0.614,and microbial activity(microbial carbon)with a SDE of 0.591,respectively.In addition,meteorological conditions have an important impact on the respiration components during the growing season.Specifically,the atmospheric vapor pressure is the dominant factor regulating the three respiration components(standardized total effects=0.44−0.53,p<0.001).The optimal soil water contents during the growing season(water content at which R_(e)reaches the maximum

关 键 词：Ecosystem respiration Respiration components Atmospheric vapor pressure Alpine grassland PERMAFROST QinghaieTibet Plateau 

分 类 号：S15[农业科学—土壤学]