长江源多年冻土区流域高寒草甸和沼泽草甸水分来源对比研究  

Comparative Study of Plant Water Sources in Alpine Meadows and Swampy Meadows in Perennial Permafrost Zone at Source Region of Yangtze River

作　　者：牛岩岩 刘光生 邓国江 施雨卿 陈旭 NIU Yan-yan;LIU Guang-sheng;DENG Guo-jiang;SHI Yu-qing;CHEN Xu(School of Environmental Science and Engineering,Xiamen University of Technology,Xiamen 361024,China;Fujian Engineering and Research Center of Rural Sewage Treatment and Water Safety,Xiamen 361024,China)

机构地区：[1]厦门理工学院环境科学与工程学院,福建厦门361024 [2]厦门市水资源利用与保护重点实验室,福建厦门361024

出　　处：《水电能源科学》2025年第4期6-11,共6页Water Resources and Power

基　　金：国家自然科学基金项目(51809222)。

摘　　要：高寒植被生长和分布与其潜在水分来源和水分利用特征密切相关。受气候变化影响,近年来长江源区植被覆盖迅速提升,大量高寒草甸演化为沼泽草甸,对区域生态水文过程产生了深远影响。基于此,采集2021年长江源多年冻土区流域典型高寒草甸和沼泽草甸坡面上坡、中坡、下坡的土壤、植物样品,获取氢氧稳定同位素监测数据,探究高寒草甸和沼泽草甸的水分利用策略差异。结果表明,叶片水δ^(18)O变幅最大,降水次之,土壤水、根系水变幅最小,叶片水氢氧稳定同位素受蒸发分馏效应影响最大,此外,植物水线的斜率和截距均远小于地区大气降水线,也反映出蒸腾作用下同位素富集现象;相比沼泽草甸,高寒草甸叶片水更加富集δ^(18)O,高寒草甸蒸腾作用更强烈;高寒草甸和沼泽草甸对不同深度土壤水的利用策略较为接近,无显著性差异,其中,0~5 cm深度土壤水的贡献比例最大,均超过22%;坡位因素对高寒草甸和沼泽草甸不同深度土壤水的利用策略无显著性影响,其中,不同坡位草甸0~5 cm土壤水的用水贡献均为最大,可见浅层土壤水为植物根系水的主要来源,当浅层土壤水无法满足植物需水时,植物根系会吸收较深层的土壤水。Plant growth and its distribution are closely related to potential water sources and their water utilization characteristics.Under the influence of climate change,the vegetation cover in the Yangtze River source area has increased rapidly in recent years,and a large number of alpine meadows have evolved into swamp meadows,which has had far-reaching impacts on the regional ecohydrological processes.This study collected soil and plant samples from the upper,middle and lower slopes of typical alpine meadows and swamp meadows on the slopes of the Yangtze River source perennial permafrost zone watershed in 2021 to obtain hydrogen and oxygen stable isotope monitoring data and to investigate the differences in water utilization strategies between alpine meadows and swamp meadows.The results show that theδ^(18)O variation of leaf water was the largest,followed by precipitation,and theδ^(18)O variation of soil water and root water was the minimum,indicating that the leaf water hydroxide stable isotopes were most affected by the fractionation effect.The slope and intercept of the plant water line are much smaller than the regional atmospheric precipitation line,showing the isotope enrichment phenomenon under transpiration.Compared with the marshy meadow,the leaf water of alpine meadow was more enriched inδ^(18)O,indicating that the transpiration of alpine meadow plant leaves was more intense.The utilization strategies of alpine meadows and swampy meadows for soil water at different depths were close to each other,and there was no significant difference.The soil water with 0-5 cm depth had the largest contribution,which was more than 22%.The slope position factor has no significant effect on the utilization strategy of soil water at different depths in alpine meadow and marshy meadow.The water use contribution of 0-5 cm soil water in meadows with different slope positions was the largest,indicating that shallow soil water is the main source of plant root water.When shallow soil water cannot satisfy the water demand of pl

关 键 词：长江源 氢氧稳定同位素 土壤水 植物水 用水策略 

分 类 号：P333[天文地球—水文科学] TV12[水利工程—水文学及水资源]