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干旱区地理 ›› 2021, Vol. 44 ›› Issue (3): 691-699.doi: 10.12118/j.issn.1000–6060.2021.03.11

• 塔里木河流域生态与环境 • 上一篇    下一篇

塔里木河下游输水对荒漠河岸林生态系统水分利用效率的影响

郝海超1,2,3(),郝兴明1,2(),成晓丽4,张静静1,2,3,范雪2,5,李远航2,5   

  1. 1.中国科学院新疆生态与地理研究所,荒漠与绿洲生态国家重点实验室,新疆 乌鲁木齐 830011
    2.新疆阿克苏绿洲农田生态系统国家野外科学观测研究站,新疆 阿克苏 843017
    3.中国科学院大学,北京 100049
    4.太原师范学院,山西 晋中 030619
    5.新疆师范大学,新疆 乌鲁木齐 830054
  • 收稿日期:2021-02-07 修回日期:2021-03-09 出版日期:2021-05-25 发布日期:2021-06-01
  • 通讯作者: 郝兴明
  • 作者简介:郝海超(1994-),男,硕士,主要从事生态水文研究. E-mail: haohaichaol8@mails.ucas.ac.cn
  • 基金资助:
    西部之光交叉团队项目(E0284101);科技部科技基础资源调查专项(2019FY100203)

Effects of ecological water conveyance on water use efficiency of desert riparian forest ecosystem in the lower reaches of Tarim River

HAO Haichao1,2,3(),HAO Xingming1,2(),CHENG Xiaoli4,ZHANG Jingjing1,2,3,FAN Xue2,5,LI Yuanhang2,5   

  1. 1. State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, Xinjiang, China
    2. Aksu National Station of Observation and Research for Oasis Agro-ecosystem, Aksu 843017, Xinjiang, China
    3. University of Chinese Academy of Sciences, Beijing 100049, China
    4. Taiyuan Normal University, Jinzhong 030619, Shanxi, China
    5. Xinjiang Normal University, Urumqi 830054, Xinjiang, China
  • Received:2021-02-07 Revised:2021-03-09 Online:2021-05-25 Published:2021-06-01
  • Contact: Xingming HAO

摘要:

水分利用效率(Water use efficiency,WUE)作为评价植物生长适宜度的综合指标之一,能很好地反映植被对生态输水的响应。通过Slope趋势分析、Pearson相关性分析及栅格时序合成等方法,利用CASA模型估算的净初级生产力(Net primary productivity,NPP)和SEBAL模型估算的实际蒸散发(ET),研究了塔里木河下游WUE的时空变化及其对生态输水的动态响应。结果表明:(1)2001—2018年,塔里木河下游WUE呈显著上升趋势(P<0.05),但受NPP的影响大于ET(CorNPP=0.76>CorET=0.10),灌丛WUE(0.49 g C·mm-1·m-2)高于胡杨(0.30 g C·mm-1·m-2)及草本(0.24 g C·mm-1·m-2);WUE空间变化规律为由河道向两侧及由西北向东南呈递减趋势,极显著上升面积占整个研究区的13.64%。(2)各植被WUE随着生态输水量的增加,呈显著上升趋势(P<0.05),灌丛WUE平均每年上升幅度是胡杨和草本WUE上升幅度的15倍,表明灌丛WUE对生态输水的响应更为敏感;各植被WUE与生态输水量、输水持续时间均呈正相关,与输水开始时间呈负相关。年内输水次数与年内WUE、NPP及归一化植被指数(NDVI)呈正相关关系(WUE:Cor=0.407,NPP:Cor=0.605,NDVI:Cor=0.657)。(3)不同植被类型生长的最适温度有所差异,并与WUE、NPP及ET有着密切关系。胡杨年均最适温度25.62 ℃、灌丛27.07 ℃及草本23.22 ℃。在温度偏差值最小的时间(4—10月)进行最佳的水热组合将更有利于植被生长。(4)塔里木河下游年均WUE与地下水埋深呈较强的负相关关系(Cor=-0.81),其中草本及灌丛WUE与地下水埋深的相关性高于胡杨(|Cor草本及灌丛=-0.76|>|Cor胡杨=-0.46|);各植被年均WUE在地下水埋深4~6 m处存在峰值,超过6 m后,WUE均呈下降趋势。

关键词: 塔里木河, 生态输水, 水分利用效率, 地下水埋深, 植被类型, 最适温度

Abstract:

Water use efficiency (WUE) refers to carbon absorbed per unit of water loss in the ecosystem. It is a comprehensive indicator used in evaluating the suitability of plant growth under water deficit and can well reflect the response of vegetation to ecological water conveyance. In this paper, the net primary productivity (NPP) estimated using the CASA model and evapotranspiration (ET) estimated using the SEBAL model are used to calculate the ecosystem WUE. Spatiotemporal changes in the ecosystem WUE in the lower reaches of Tarim River, Xinjiang, China are studied using slope trend analysis, Pearson correlation analysis, and grid time sequence synthesis, and the changes were found to be affected by ecological water conveyance, meteorological elements, and groundwater level. The results show the following: (1) from 2001 to 2018, the WUE in the lower reaches of Tarim River exhibited a significant fluctuation (P<0.05), whereas, the influence of NPP was greater than that of ET (CorNPP=0.76>CorET=0.10). The WUE of shrubs (0.49 g C·mm-1·m-2) is higher than that of Populus euphratica (0.30 g C·mm -1·m-2) and herbs (0.24 g C·mm-1·m-2). The spatial variation of WUE is based on the river channel and shows a decreasing trend to both sides and from northwest to southeast. The extremely significant increase in area accounts for 13.64% of the entire study area. (2) From 2001 to 2018, the WUE of various vegetations showed a significant upward trend with increasing ecological water conveyance (P<0.05). The average annual increase in the WUE of shrubs was 15 times that of P. euphratica and herbs. The response is also more sensitive. The WUE values of P. euphratica, shrubs, and herbs are positively correlated with ecological water conveyance and the duration of water conveyance and negatively correlated with the start time of water conveyance. The WUE of shrubs has the highest correlation with the three. (3) There is a positive correlation between the number of water conveyance times and WUE, NPP, and normalized difference vegetation index (NDVI) during the year (WUE: Cor=0.407, NPP: Cor=0.605, NDVI: Cor=0.657). In addition, the optimum temperature (TEM) and NDVI are related to WUE and NPP, and the spatial distribution of ET is highly consistent. Populus euphratica has an average annual optimum temperature of 25.62 ℃, shrubs have 27.07 ℃, and herbs have 23.22 ℃. At this time, the best combination of water and heat will be more conducive to vegetation survival. (4) There is a strong negative correlation between the annual WUE and the groundwater level in the lower reaches of Tarim River (Cor=-0.81), and WUE decreased by about 0.01 g C·mm-1·m-2 every meter. The correlation between the WUE of herbs and shrubs and groundwater level is greater than that of P. euphratica (|Corherbs and shrubs=-0.76|>|CorP. euphratica=-0.46|), and the average WUE of P. euphratica, shrubs, herbs, and groundwater level is 4-6 m, with a peak at 6 m. Above 6 m, the average annual WUE and WUE of each vegetation show a downward trend.

Key words: Tarim River, ecological water conveyance, water use efficiency, groundwater depth, vegetation type, optimum temperature