| 土地利用变化对生态系统服务功能的影响——以密云水库流域为例 |
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| 作者姓名： | 李屹峰 罗跃初 刘纲 欧阳志云 郑华 |
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| 基金项目： | 中国主要陆地生态系统服务功能与生态安全(2009CB421105);国土资源部公益性行业科研专项项目(201011018); 中国科学院国际合作项目(GJHZ0948);戈登和贝蒂摩尔基金 |
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| 摘 要： | 生态系统服务功能与人类福利息息相关,土地利用变化是生态系统服务功能退化的主要驱动力之一,以人地关系紧张,生态系统服务功能变化剧烈的密云水库流域为对象,分析流域1990-2009年土地利用的变化,采用空间显式的生态系统服务功能评估软件InVEST中的“产水量”、“土壤保持”、“水质净化”模型,研究流域土地利用变化对生态系统服务功能的影响.结果表明1990-2009年密云水库流域土地利用变化剧烈,农田、草地和水体的面积分别减少了30％、48％、61％,林地、建筑用地和裸地的面积增加,增幅分别为30％、230％、282％.随着土地利用变化,生态系统服务功能相应产生着显著变化,研究期内,土壤保持功能和固碳服务分别增加46％和19％,但水资源供给服务和水质净化功能分别减少了3％和25％.农田面积的减少和森林的扩张改善了土壤保持服务,森林面积的增加同时也改善了固碳服务,但会削弱水资源供给服务,建筑用地的扩张会大幅度削弱水质净化功能,为维持和改善流域整体的生态系统服务功能,应加强对森林和建筑用地的控制.其研究为密云水库流域土地利用科学管理决策提供参考.
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| 关 键 词： | 生态系统服务功能 土地利用 InVEST模型 |
Effects of land use change on ecosystem services: a case study in Miyun reservoir watershed |
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| Authors: | LI Yifeng LUO Yuechu LIU Gang OUYANG Zhiyun and ZHENG Hua |
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| Abstract: | Ecosystem services are the goods and services provided by ecosystems to people. Ecosystem services are important basis of human existence and strongly related to human well-being, and the sustainable provision of multiple services is essential for the sustenance of human societies. There are a series of factors driving ecosystem services, one of which is the change of land use pattern, and it is drawing more and more attention of ecologists.
Miyun reservoir, which is the only surface water source for domestic water in Beijing, plays the key role for the ecological security of the capital. Miyun reservoir watershed is a vital water source region of Beijing city, and it has many important ecosystem services. The water yield and water quality of reservoir strongly depend on Miyun reservoir watershed''s condition, therefore, the conservation and improvement of ecosystem services in Miyun reservoir watershed has vital significance for local and Beijing''s ecological security. However, how the land use change influenced ecosystem services during the past decades is not clear yet, which may block the comprehensive development of watershed.
So we take Miyun reservoir watershed as example, analyze the change of land use and ecosystem services between 1990 and 2009. We set up a two-grade classify system of land use and interpreted the remote sensing images of 1990, 2000 and 2009 respectively, and then apply Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST model), which is a space explicit model and based on land use, to map the ecosystem services, and analyze the influence of Land Use to ecosystem services during study period. The sub models we apply in this research contain "Water Yield", "Sediment Retention" and "Water Purification", and before running these sub models, we verify them with observed data.
The results of image interpretation show that farmland, forest and grassland are main type of land use of watershed, and these areas account for more than 95% of the whole watershed. There are sharp changes of land use during study period, and conversion of land use types distributed more widely after 2000. The general trend in study period is farmland and grassland decreased by 30%, 48% respectively, when forest increased by 30%, and another change cannot be neglected is residential area expanded by more than 280% during the past 20 years.
The changes of land use have affect on the pattern of ecosystem services and there are trade-offs among different ecosystem services in question. During the study period, the decreasing of farmland and increasing of forest and grassland improved the ability of sediment retention, and this service increased by 46% in the past 20 years. But forest expansion caused more evapotranspiration, which reduced water yield of watershed by 3% at the same time. Because the nutrient loading of residential area is much higher than other types of land use, the large-scale expansion of residential area decreased water purification service sharply after 2000 although the expansion of forest and decrease of farmland can improve this service to a certain degree, and this service declined by 55% in the past 20 years. With the expansion of forest, carbon sequestration service increased about 19%. So with the goal to get overall improvement of ecosystem services in watershed, we suggest that manages should strengthen the control of forest and residential areas.
Understanding the relationship between land use and ecosystem services, the department of decision-making can control and reduce the trade-off between ecosystem services and achieve the sustainable development through appropriate land use plan. Although the approach and process of evaluation still need more improvement, our research can provide scientific foundation for decision-making in Miyun reservoir watershed. |
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| Keywords: | ecosystem services land use InVEST model |
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