摘要
氮(N)和磷(P)养分有效性是制约森林生态系统林分生产力与碳汇功能的关键要素,但目前对多变环境下森林生态系统养分限制特征还缺乏充分的科学认识。山地生态系统的气候、植被和土壤等环境因子沿海拔的垂直变化格局为深入认识森林养分限制及其驱动因素提供了天然的实验平台。该研究以青藏高原东缘典型的川西亚高山针叶林——岷江冷杉(Abies faxoniana)林为研究对象,通过沿巴朗山2 850–3 200m海拔梯度的多点取样,从植物叶片N、P养分含量、化学计量变化和地下微生物胞外酶化学计量学的角度,分析了海拔梯度下该区域森林养分限制特征变化规律及其主要驱动因素。结果表明:1)随海拔升高,叶片N、P含量降低而N:P由12.33升高至15.00,表明随海拔升高该区域针叶林叶片生长由N限制转化为N-P共同限制,且P限制随海拔升高而表现出增强趋势;2)矢量模型分析发现不同海拔下根际土壤微生物胞外酶化学计量矢量角度均>45°,且随海拔升高呈上升趋势,表明该区域微生物受P限制,且海拔越高土壤微生物P限制越强;3)进一步通过Pearson相关分析和路径分析表明,海拔引起的气温变化是驱动岷江冷杉林生态系统养分限制的主导因素。综上所述,基于叶片和土壤微生物养分证据均表明川西亚高山针叶林生态系统总体表现出P限制程度随海拔升高而逐渐增强的趋势。
Aims Nitrogen(N)and phosphorus(P)nutrient availability is a key factor governing forest productivity and carbon sequestration.However,scientific knowledge on the nutrient limitation in forest ecosystems under variable environments is still lacked.The mountain ecosystems,characterized by the dramatical changes in multiple environmental factors along increasing altitude such as climate,vegetation and soil properties,provide a natural experiment platform for understanding forest nutrient limitation and its drivers.Methods In this study,we examined the nutrient limitation of a typical subalpine coniferous forest(Abies fargesii var.faxoniana forest)along an altitudinal gradient(from 2850 m to 3200 m)in the southeastern Qingzang Plateau,by simultaneous detection of above-ground leaf N,P status and underground microorganisms extracellular stoichiometry,and analyzing the changes of forest nutrient limitation and the main driving factors along the altitude.Important findings The results showed that:1)as altitude increases,the concentration of leaf N and P decreased,while leaf N:P increased from 12.33 to 15.00,indicating a shift from N limitation to N-P co-limitation and an enhancement of P limitation with increasing altitude.(2)Vector model analysis showed that the vector angles of microbial extracellular enzyme stoichiometry were all exceed 45°at different altitudes,and as altitude increases,the vector angle showed an increasing trend,indicating that microorganisms were limited by P and the P limitation increases with altitude.(3)Temperature is the dominant factor driving nutrient limitation of Abies fargesii var.faxoniana forest.Collectively,both leaf and soil microbial nutrient evidence indicated that an enhancement of P limitation in subalpine coniferous forests with increasing altitudes in western Sichuan.This finding could provide an important theoretical basis for guiding forest nutrient adaptive management in subalpine coniferous ecosystems under the scenarios of global climate change.
作者
何茜
冯秋红
张佩佩
杨涵
邓少军
孙小平
尹华军
HE Xi;FENG Qiu-Hong;ZHANG Pei-Pei;YANG Han;DENG Shao-Jun;SUN Xiao-Ping;YIN Hua-Jun(China-Croatia“Belt and Road”Joint Laboratory on Biodiversity and Ecosystem Services,CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization,Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province,Chengdu Institute of Biology,Chinese Academy of Sciences,Chengdu 610041,China;University of Chinese Academy of Sciences,Beijing 100049,China;Sichuan Academy of Forestry,Sichuan Wolong Forest Ecosystem Research Station,Chengdu 610081,China;Aba State Owned Forest Protection Bureau,Aba,Sichuan 624000,China)
出处
《植物生态学报》
CAS
CSCD
北大核心
2023年第12期1646-1657,共12页
Chinese Journal of Plant Ecology
基金
中国科学院“西部之光”交叉团队项目(xbzg-zdsys-202112)
第二次青藏高原综合科学考察项目(2019QZKK0301)
国家自然科学基金(32171757和32201531)
中国博士后科学基金(2021M703133)。
关键词
海拔
养分限制
N:P
土壤胞外酶化学计量
亚高山针叶林
altitude
nutrient limitation
N:P
soil extracellular enzyme stoichiometry
subalpine coniferous forest