石羊河流域水分利用效率及其对饱和水汽压差的响应  

Spatial-temporal dynamics of water use efficiency and responding to vapor pressure deficit in Shiyang River Basin,northwestern China

作　　者：王大为 赵成章 方锋 林婧婧 李丽丽 杨永明 WANG Dawei;ZHAO Chengzhang;FANG Feng;LIN Jingjing;LI Lili;YANG Yongming(Research Center of Wetland Resources Protection and Industrial Development Engineering of Gansu Province,College of Geography and Environmental Science,Northwest Normal University,Lanzhou 730070,China;College of Earth Science and Engineering,West Yunnan University of Applied Sciences,Dali 671006,China;Lanzhou Regional Climate Center,Lanzhou 730020,China;Yulong Snow Mountain National Field Observation and Research Station for Cryosphere and Sustainable Development,Lijiang 674100,China)

机构地区：[1]西北师范大学地理与环境科学学院,甘肃省湿地资源保护与产业发展工程研究中心,兰州730070 [2]滇西应用技术大学地球科学与工程学院,大理671006 [3]兰州区域气候中心,兰州730020 [4]玉龙雪山冰冻圈与可持续发展云南省野外科学观测研究站,丽江674100

出　　处：《生态学报》2023年第8期3090-3102,共13页Acta Ecologica Sinica

基　　金：国家自然科学青年基金项目(41705062,32071606);甘肃省气象局研究型业务重点项目(ZD2021-02);云南省教育厅项目“云南省高校山地实景点云数据处理及应用重点实验室”。

摘　　要：水分利用效率(WUE)是叶片通过光合作用调节水分生理过程的指标,是联系生态系统碳循环与水循环关系的关键,反映了植被生态系统对立地环境快速调整和资源的变化适应策略。基于卫星遥感和地面观测数据,利用光能利用率模型和蒸散发经验估算模型,模拟石羊河流域2000—2019年植被总初级生产力(GPP)和蒸散发(ET)数据,估算2000—2019年不同植被类型的WUE空间分布特征,研究GPP/ET/WUE与饱和水汽压差(VPD)的相关性,探讨干旱区不同类型植被对水分利用及胁迫的适应策略。结果表明:(1)2000—2019年石羊河流域植被WUE、GPP和ET的平均值分别为0.80 gC m^(-2)mm^(-1)、256.52 gC/m2和302.52 mm,其三者的空间分布特征表现为“南高北低”,即由流域源头至下游逐渐减少的空间分布。(2)近20年内,流域内WUE、GPP和ET的变化率的平均值分别为0.017 gC m^(-2)mm^(-1)a^(-1),6.99 gC m-2a^(-1)和3.80 mm/a,流域总体呈现波动上升的趋势,但城区和民勤耕地-荒漠交接区呈不同程度的减少趋势。(3)流域内不同类型植被的WUE平均值关系为:森林>农作物>草地>灌丛>荒漠植被>湿地植被,WUE增加速度的平均值关系为:农作物>森林>草地>灌丛>荒漠植被>湿地植被,与GPP基本一致,其中ET在灌丛、荒漠植被、湿地植被地区呈现降低趋势。(4)研究区内GPP/ET/WUE与VPD相关性的空间分布特征与石羊河径流方向具有高度一致性,WUE与VPD相关性分布特征受土地利用以及径流方向影响显著。WUE与VPD呈正相关的区域主要分布在河西走廊绿洲东部和荒漠区东部,呈负相关区域主要分布在祁连山高海拔地区、河西走廊绿洲中部和荒漠区西部。因此,正确揭示内陆河植被GPP/ET/WUE的空间分异以及变化趋势及其对驱动因素VPD的响应,是了解流域尺度中干旱区植被对全球干旱加剧的适应性策略前提,进而为生态保护提供决策服务。Water use efficiency(WUE)is the regulation index of leaf photosynthesis on the water physiological process,as the key to link the relationship between the ecosystem carbon cycle and the water cycle,and directly reflects the rapid adjustment of the ecosystem to the site environment and the adaptation strategy of resource changes.The Gross primary production(GPP)temporal and spatial characteristics derived from the data of MODIS-NDVI by the Light Energy Utilization Model,and the Evapotranspiration(ET)temporal and spatial characteristics derived from the meteorological data by the Thornthwaite Evapotranspiration Model during 2000-2019 in Shiyang River Basin(SRB).In this research,we estimated the spatial pattern and temporal variations of the GPP,ET and WUE in different vegetation types from 2000 to 2019,investigated the co-relationship between GPP/ET/WUE and Vapor pressure deficit(VPD),and discussed the response of adaptation strategies for water utilization and stress in the arid area among the different vegetation.The results show that:(1)from 2000 to 2019,the average annual value of total WUE,GPP,and ET in SRB were 0.80 gC m-2 mm-1,256.52 gC/m2,and 302.52 mm,respectively;The spatial patterns of average annual WUE,GPP and ET in the SRB's vegetated areas varied widely,and the values decreased from upstream on the south side of the Qilian Mountains and middle to downstream on the north side of the desert.(2)During the 20 years,the average slope of WUE,GPP,and ET showed an obvious upward trend in almost whole basin,with the rate of 0.017 gC m-2 mm-1 a-1,6.99 gC m-2 a-1 and 3.80 mm/a.The change rates of WUE,GPP and ET within the basin exhibited an upward trend,except for Liangzhou and the areas surrounding Minqin cropland according to the urbanization and industrial adjustment.(3)The WUE,GPP and ET annual average values,and slope of trends among the different land use types also varied significantly.Among various vegetation types,the highest values of WUE,GPP and ET appeared in forests,and the lowest values presented

关 键 词：水分利用效率 植被总初级生产力 蒸散发 植被类型 饱和水汽压差 相关性 石羊河 

分 类 号：Q948[生物学—植物学]