干旱胁迫下植被生产力与冠层结构易损性的非一致性评估  

Assessing the non-uniform vulnerability of vegetation productivity and canopy structure under drought stress

作　　者：张璐[1] 畅建霞[1] 杨贵斌 郭爱军[1] 王义民[1] ZHANG Lu;CHANG Jianxia;YANG Guibin;GUO Aijun;WANG Yimin(State Key Laboratory of Water Engineering Ecology and Environment in Arid Area,Xi’an University of Technology,Xi'an 710048,China)

机构地区：[1]西安理工大学旱区水工程生态环境全国重点实验室,西安710048

出　　处：《农业工程学报》2025年第6期145-153,共9页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家自然科学基金重点项目(U2243233)。

摘　　要：频繁的干旱事件已对植被正常生长与生态系统稳定构成威胁。为解析干旱对植被影响的复杂性,该研究基于Copula模型,利用归一化植被指数、总初级生产力和标准化降水蒸散发指数,构建了气象干旱胁迫下植被生产力与冠层结构损失的条件概率模型,并运用偏最小二乘路径模型,探讨了植被对干旱响应的驱动因子。结果表明,1982—2018年长江流域植被生产力、冠层结构对气象干旱的滞后响应在时间维和空间维呈现出非一致性特征。时间上,植被生产力对气象干旱的响应时间较冠层结构更长;空间上,汉江流域和长江中下游干流区植被生产力易损性高,而金沙江流域和长江干流区间冠层结构易损性高。不同类型植被的易损性不同,水田和常绿阔叶林的生产力损失概率较高,分别为21.05%、17.26%,草地和常绿针叶林的冠层结构损失概率更大,分别为36.35%、35.73%。此外,植被生产力与冠层结构的关键环境影响因子不同,前者主要受控于冠层结构和土壤水分,后者则对海拔和气候因子更为敏感。研究成果有助于深入了解干旱对植被的影响,进而为生态系统管理与保护提供重要的科学依据。Frequent and severe drought events have posed the serious threat to vegetation growth and ecosystem stability.The underlying dynamics of vegetation response to droughts can be expected to predict and mitigate the impacts of these environmental stresses on ecosystems.However,a single ecological index cannot fully meet the requirements of the vegetation responses to droughts.In this study,a robust conditional probability model was constructed to combine the normalized difference vegetation index(NDVI),gross primary productivity(GPP),and the standardized precipitation and evapotranspiration index(SPEI).The Copula framework was designed to clarify the relationships between meteorological drought stress and the probabilities of vegetation productivity and canopy structure loss.Additionally,a systematic investigation was also made to explore the interactions between different vegetation growth statuses and environmental factors,as well as the driving forces behind drought trigger thresholds using partial least squares path modeling(PLS-PM).A case study was also carried out in the Yangtze River Basin(YRB)from 1982 to 2018.The temporal and spatial disparities were observed in the vegetation productivity and canopy structure response to the meteorological droughts.The results indicate that:1)The proportion of areas where vegetation productivity and canopy structure in the YRB are positively correlated with SPEI is 50.61%and 63.04%,respectively..Notably,the canopy structure exhibited a closer association with the SPEI,compared with the vegetation productivity.There was a shorter response time to the meteorological drought stress.The canopy structure shared the higher vulnerability under drought duress,compared with the vegetation productivity.2)Spatially,the high vulnerability was found in regions,such as the Hanjiang Basin and the middle and lower reaches of the Yangtze River,in terms of vegetation productivity.While the increasing susceptibility of canopy structure was displayed in the Jinsha River Basin and the mainstre

关 键 词：植被生产力 冠层结构 植被响应 触发阈值 长江流域 

分 类 号：S127[农业科学—农业基础科学]