干旱区研究 ›› 2023, Vol. 40 ›› Issue (4): 563-572.doi: 10.13866/j.azr.2023.04.05 cstr: 32277.14.j.azr.2023.04.05

• 水土资源 • 上一篇    下一篇

无定河流域土地覆被空间分异机制及相关水碳变量变化

吕锦心1,2(),梁康1(),刘昌明1,张仪辉1,2,刘璐1,2   

  1. 1.中国科学院地理科学与资源研究所,中国科学院陆地水循环及地表过程重点实验室,北京 100101
    2.中国科学院大学,北京 100049
  • 收稿日期:2022-03-22 修回日期:2022-12-24 出版日期:2023-04-15 发布日期:2023-04-28
  • 作者简介:吕锦心(1996-),女,硕士研究生,主要从事干旱区水文水资源研究. E-mail: lvjx.19s@igsnrr.ac.cn
  • 基金资助:
    国家自然科学基金项目(41971035);中国科学院青年创新促进会会员人才专项(2019054);中国科学院地理科学与资源研究所 “秉维”优秀青年人才计划项目(2017RC204)

Spatial differentiation mechanism of land cover and related changes in water-carbon variables in Wuding River Basin

LYU Jinxin1,2(),LIANG Kang1(),LIU Changming1,ZHANG Yihui1,2,LIU Lu1,2   

  1. 1. Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
    2. University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2022-03-22 Revised:2022-12-24 Published:2023-04-15 Online:2023-04-28

摘要:

无定河流域是黄土高原生态恢复工程实施的重点区,探究其土地覆被的空间分异机制及相关水碳变量的变化特征,对支撑区域水土资源保护与规划以及服务区域生态文明建设等工作具有重要作用。本文使用线性倾向法、Mann-Kendall趋势检验、Pettitt突变检验、地理探测器等方法分析无定河流域土地覆被时空变化特征及空间分异驱动因素,并从地-水-碳耦合的角度探析流域总初级生产力(GPP)、实际蒸散发(ET)和水分利用效率(WUE)等关键水碳变量的变化特征。研究表明:(1) 1990—2019年期间,流域整体草地、林地、建设用地显著增加,耕地、荒地显著减少,其中林草面积增加区域主要集中在流域下游及无定河沿岸地区;(2) 人口密度、降水、气温等对流域土地覆被空间格局具有重要影响,整体而言社会经济因素的影响大于自然因素,但以降水、气温为代表的自然因素的影响在增强;(3) 流域水碳变量的变化与土地覆被变化具有较好的对应关系,空间上,以耕地、林地、草地为主要覆被的流域东南部的GPP、ET、WUE相对偏高,以草地、荒地为主要覆被的流域西北部的GPP、ET、WUE相对偏低,时间上,2001—2019年间,流域整体GPP、ET、WUE均呈增加趋势,其中GPP、WUE在流域绝大部分区域均显著增加,而ET主要在流域中下游地区显著增加。在退耕还林还草生态恢复工程的实施与气候变化背景下,无定河流域林草得到恢复,生态环境转好。

关键词: 黄土高原, 覆被变化, 实际蒸散发, 总初级生产力, 水分利用效率, 地理探测器

Abstract:

The Wuding River Basin is the key area for the implementation of the grain for green program on the Loess Plateau. Exploring the spatial differentiation mechanism of land cover and the characteristics of variation of related water-carbon variables is essential for supporting water and soil resources conservation and planning, along with serving the construction of regional ecological civilization. Here we used the linear tendency method, Mann-Kendall trend test, Pettitt test, and geodetector to analyze the spatiotemporal characteristics and the factors driving the spatial differentiation of land cover in Wudinghe River Basin. In addition, from the perspective of land-water-carbon coupling, we analyzed the characteristics of variation of total primary productivity (GPP), actual evapotranspiration (ET), and water use efficiency (WUE). Three main results were as follows: (i) The total grassland, forest, and construction land increased significantly, while the cropland and barren land decreased significantly during 1990-2019. The area of forest and grassland increased mainly in the lower reaches of the basin and along Wuding River. (ii) Population density, precipitation, and temperature have a significant impact on the spatial pattern of land cover. On the whole, the influence of socioeconomic factors is greater than that of natural factors, but the influence of natural factors represented by precipitation and temperature is increasing. (iii) There is a good correlation between the variation of water-carbon variables and land cover change. Spatially, GPP, ET, and WUE are relatively high in the southeastern part of the basin where cropland, forest, and grassland are the main cover, while they are lower in the northwestern part of the basin where grassland and barren land are the main cover. In terms of time, GPP, ET, and WUE all showed increasing trends during 2001-2019. GPP and WUE increased significantly in most parts of the basin, while ET increased significantly mainly in its middle and lower reaches. In conclusion, under the implementation of the grain for green program and climate change, the forest and grass in Wudinghe River Basin have been restored and the ecology has been improved.

Key words: the Loess Plateau, land cover change, actual evapotranspiration, gross primary productivity, water use efficiency, geodetector