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全球生态系统土壤保持服务变化及其影响因素
Alternative TitleAnalysis of Spatial and Temporal Changes and Driving Forces of Global Soil Conservation Services
熊木齐
Subtype博士后
Thesis Advisor陈利顶 ; 孙然好
2019-08
Degree Grantor中国科学院生态环境研究中心
Place of Conferral北京
Degree Name理学
Degree Discipline生态学
Keyword土壤保持 服务 ,土壤侵蚀,通用土壤流失方程,生态系统 Soil Conservation, Soil Erosion, Universal Soil Loss Equation, Ecosystem Service
Abstract

      土壤侵蚀是威胁生态安全的全球性问题之一,土壤保持是生态系统重要调节服务之一。土壤保持服务功能空间格局是明确土壤保持重要区域,实现土壤保持的基础和前提。近几十年来,全球社会经济高速发展, 人类活动加剧,生态系统受到不同程度的干扰, 部分 生态系统退化。与此同时,随着环境意识的提高,部分国家和地区实施了生态保护措施 。对全球 过去 生态系统土壤保持服务功能的空间格局和变化趋势 的 评估,能为未来土壤保持提供参考 。
      本研究收集全球径流小区数据,对土壤 侵蚀 (水蚀 进行了全球范围评估; 基于 通用土壤流失方程系列模型( USLE/RUSLE 结合 RS、 GIS和 统计学等 分析方法 ,计算和优化影响土壤保持的各个因子 建立 1992~2015年栅格数据库 进行全球土壤侵蚀 风险 评价并验证结果;最后开展全球生态系统土壤保持功能评估,分析空间格局和变化特征,揭示 土壤保持服务 变化驱动因素。主要研究结果如下:
      (1) 基于全球范围内径流小区监测数据 评估全球 土壤侵蚀 ,发现 裸地、 农田和园地的年平均土壤侵蚀强度远高于草地 、灌丛和森林 。不同 气候带 之间,同一土地覆被类型 土壤的侵蚀强度存在很大差异 如 热带和温带 裸地 土壤侵蚀强度均值大于 100 t·ha-1·yr-1,而寒带和干旱区 裸地 均值分别为 54.1 t·ha-1·yr-1和 10.6 t·ha-1·yr-1;农田的土壤侵蚀均值 也有明显差异: 热带( 41.8 t·ha-1·yr-1)、 暖温带 17.8 t·ha-1·yr-1)、 寒温带 21.8 t·ha-1·yr-1)和 干旱带 3.9 t·ha-1·yr-1)。
      (2) 利用 Meta分析的方法 对全球范围内水土保持措施效应 数据 进行分 析发现 水土保持措施能 使年均 土壤流失量减少 地形坡度对水土保持措施 的效率也 有显著影响, 并 基于 此 量化了 全球水土保持 P因子 。
      (3) 基于 RUSLE模拟 1992~2015年 全球土壤 侵蚀 时空格局 可知 全球 土壤侵蚀( 侵蚀 强度 > 2 t·ha-1·yr-1)面积为约 1742.47万 km2,平均 土壤侵蚀强度 约 5.78 2 t·ha-1·yr-1 农田是全球土壤侵蚀的主要来源。 空间上,全球土壤 侵蚀严重区域主要集中在 亚洲 、 非洲 和 南美洲 ,贡献了全球 89.39%的土壤 侵蚀量。 全球土壤侵蚀呈增加趋势 变化斜率为 4.26×10-3 t·ha-1·yr-2。
      (4) 模拟全球生态系统土壤保持服务空间 格局 可知 全球生态系统年均土壤保持 强度约为 2 28.22 2 t·ha-1·yr-1,平均土壤保持率 达到 95.87%。各类生态系统在土壤保持方面发挥了重要的作用,尤其是森林生态系统土壤保持总量占比全球土壤保持总量的 68.74%。全球土壤保持极重要区面积为 244.12万 km2 主要分布在亚洲 和南美洲,占比全球极重要区面积的 基本 都是植被覆盖较好的高山区。
      (5)全球生态系统土壤保持服务功能整体增强,平均变化斜率为 0.93 t·ha-1·yr-2。 全球有 60.03%的陆地区域土壤保持服务功能呈增强趋势,其中 13.89%的区域超过 5%显著性水平,平均 变化 斜率为 8.88 t·ha-1·yr-2 40.53%的区域土壤保持服务功能呈下降趋势,其中 4.02%的区域超过 5%显著性水平,平均斜率为 -23.43 t·ha-1·yr-2。亚洲南部和南美洲局部地区土壤保持强度变化幅度较大,而北半球 寒温带 生态系统土壤保持强度普遍增强,但增强幅度比较平缓。
      (6) 分析生态系统土壤保持服务变化的影响因素, 发现 1992~2015年,全球农田开垦面积为 181.16万 km2,其中 有 森林 103.94万 km2 、灌丛 24.82万 km2和草地 23.35万 km2 转为农田,土壤保持强度 均值分别 下降 14.64%、 16.24%和此外,由于生态保护工程等的实施,部分 农田 63.9万 km2 转为森林,荒漠 42.01万 km2 转为草地,土壤保持强度平均分别提升 了 14.78% 和 71.69%。说明生态保护工程 能有效 增强土壤保持服务功能,而 农田开垦 则 导致土壤保持功能显著降低。
      综上,全球土壤侵蚀形势严峻,尤其是农田生态系统,是全球水土流失的主要来源。 1992~2015年全球生态系统土壤保持功能呈逐渐增加趋势,生态保护工程实施和城市化 使 土壤保持功能显著增强, 但 农田开垦、荒漠化使土壤保持功能 显著 减弱。

Other Abstract

      Soil erosion by water is considered as one of the major threats to ecological security. Soil conservation is an important regulating service of ecosystems. The spatial pattern of soil conservation service is important for critical area identification, and is the basis and premise of soil erosion control and ecological protection. In recent years, the rapid development of economy and society, along with intensified human activities, resulting in great reduction in ecological functions. Meanwhile, the awareness of ecological issues prompts some countries to implement a series of ecological protection and construction projects. Assessing the effectiveness of soil conservation services can provide information for scientific decision-making for better soil conservation.
      In this study, a meta-analysis of worldwide soil erosion field experimental measurements was presented. Then we assessed the global soil erosion using remote sensing, parameter calibration, model simulation and correction. Finally, we assessed the ecosystem’s soil conservation service, and analyzed the spatial pattern, trends and the driving factors. The main findings are as follows:
      (1) Bare lands, croplands and orchards had higher soil loss rates (SLs) than that of grasslands, shrublands and forestlands. The SLs of the same land use type varies greatly between different climate zones, for example, the average SLs of bare lands in tropical and temperate climate zones were greater than 100 t·ha-1·yr-1, while in cold and arid climate zones, the SLs of bare land were 54.1 and 10.6 t·ha-1·yr-1 respectively; With respect to croplands, the SLs were also different: tropical (41.8 t·ha-1·yr-1) and temperate (17.8 t·ha-1·yr-1), cold (21.8 t·ha-1·yr-1) and arid (3.9 t·ha-1·yr-1).
      (2) A comprehensive review was conducted to compare the effects of soil conservation techniques on water erosion control, the results showed that the soil conservation techniques were generally effective at reducing annual soil loss (84%), the efficiency of water erosion control varied as the terrain slope increased, and finally we quantified the soil conservation techniques factors. 
      (3) Based on the Universal Soil Loss Equation, we assessed the global soil erosion. The results show that there was about 1742.47 × 104 km2 land suffering from water erosion (SL > 2 t·ha-1·yr-1), with average soil erosion rate of 5.78 t·ha-1·yr-1. Croplands are the main source of soil erosion. Spatially, severe soil erosion are mainly located in Asia, Africa and South America, contributing 89.39% of the total amount of global soil erosion. The global water erosion was generally enhanced, with an average rate of 4.26×10-2 t·ha-1·yr-2.
      (4) From 1992 to 2015, a soil conservation capacity of 228.22 t·ha-1·yr-1 was retained by ecosystems, with a soil retention rate of 95.87%. All kinds of ecosystems play important roles in soil conservation, especially the forest ecosystems, the total amount of soil conservation accounts for 68.74% of the total global soil conservation. The global soil remains a extremely important area of 244.12×104 km2, mainly located in Asia and South America, accounting for 76.68% of the global extremely important area, which are basically high mountain areas with good vegetation coverage.
      (5) The ecosystems’ soil conservation service was generally enhanced, with an average rate of 0.93 t·ha-1·yr-2. In which, the trend exhibited a significant increase (p < 0.05) in 13.89% of global lands, with an average rate of 8.88 t·ha-1·yr-2; however, the trend exhibited a significant decrease (p< 0.05) in 4.02% of global lands, with an average rate of -23.43 t·ha-1·yr-2; The soil conservation capacity in the southern of Asia and South America varied greatly, while the soil conservation capacity in the cold climate zone generally increased, however the enhancement was relatively quietly.
      (6) From 1992 to 2015, there were forest lands (103.94×104 km2), shrublands (24.82×104 km2) andgrasslands (23.35×104 km2) converted into farmlands, which decreased its soil conservation capacity by 14.64%, 16.24% and 14.84%, respectively; There were 63.9×104 km2 of farmlands converted into forest lands, and 42.01×104 km2 of bare lands converted into grasslands, which decreased its soil conservation capacity by 14.78% and 71.69%, respectively. The results show that the ecosystems’ soil conservation service was definitely enhanced under ecological protection and restoration programs, however, reclamation, through damage to ecosystem structures, is important cause of degradation in soil conservation service.
      In short, the world is suffering from serious water erosion, especially the farmland ecosystem, which is the main source of global water erosion. While the soil conservation service of the global ecosystem gradually increased from 1992 to 2015, the implementation of ecological protection project and urbanization significantly enhanced the soil conservation service, however, the soil conservation service was significantly weakened by reclamation and desertification.

Pages126
Language中文
Document Type学位论文
Identifierhttp://ir.rcees.ac.cn/handle/311016/42325
Collection城市与区域生态国家重点实验室
Recommended Citation
GB/T 7714
熊木齐. 全球生态系统土壤保持服务变化及其影响因素[D]. 北京. 中国科学院生态环境研究中心,2019.
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