Drought can offset potential water use efficiency of forest ecosystems from rising atmospheric CO2

作     者：Ning Liu Jatin Kala Shirong Liu Vanessa Haverd Bernard Dell Keith R.J.Smettem Richard J.Harper Ning Liu;Jatin Kala;Shirong Liu;Vanessa Haverd;Bernard Dell;Keith R.J.Smettem;Richard J.Harper

作者机构：Environmental and Conservation SciencesMurdoch UniversityMurdochWA 6150 Australia Research Institute of Forest EcologyEnvironment and ProtectionChinese Academy of ForestryBeijing 10091 China CSIRO Oceans&AtmosphereACT 2600 Australia 

出 版 物：《Journal of Environmental Sciences》 (环境科学学报（英文版）)

年 卷 期：2020年第32卷第4期

页      面：262-274页

核心收录：

学科分类：07[理学] 070602[理学-大气物理学与大气环境] 09[农学] 0903[农学-农业资源与环境] 0706[理学-大气科学] 

基　　金：supported by a Murdoch University PhD Strategy Scholarship the National Key Research and Development Program of China(2018YFC0507305-2) supported by the Pawsey Supercomputing Centre’s cloud service(Nimbus) supported by an Australian Research Council Discovery Early Career Researcher Award(DE170100102) support from the Earth Systems and Climate Change Hub,funded by the Australian Government’s National Environmental Science Program 

主　　题：Water use efficiency Elevated CO2 Carbon sequestration,drought Forest Australia 

摘      要：Increasing atmospheric CO2 is both leading to climate change and providing a potential fertilisation effect on plant ***,southern Australia has also experienced a significant decline in rainfall over the last 30 years,resulting in increased vegetative water *** better understand the dynamics and responses of Australian forest ecosystems to drought and elevated CO2,the magnitude and trend in water use efficiency(WUE)of forests,and their response to drought and elevated CO2 from 1982 to 2014 were analysed,using the best available model estimates constrained by observed fluxes from simulations with fixed and time-varying *** ratio of gross primary productivity(GPP)to evapotranspiration(ET)(WUEe)was used to identify the ecosystem scale WUE,while the ratio of GPP to transpiration(Tr)(WUEc)was used as a measure of canopy scale *** increased significantly in northern Australia(p0.001)for woody savannas(WSA),whereas there was a slight decline in the WUE of evergreen broadleaf forests(EBF)in the southeast and southwest of *** lag of WUEc to drought was consistent and relatively short and stable between biomes(3 months),but notably varied for WUEe,with a long time-lag(mean of 10 months).The dissimilar responses of WUEe and WUEc to climate change for different geographical areas result from the different proportion of Tr in ***2 fertilization and a wetter climate enhanced WUE in northern Australia,whereas drought offset the CO2 fertilization effect in southern Australia.