基于改进TOPSIS方法的三峡库区生态敏感区土地利用系统健康评价

Health assessment of a land use system used in the ecologically sensitive area of the Three Gorges reservoir area,based on the improved TOPSIS Method

土地利用系统健康评价研究能够有效引导土地合理利用,协调城市发展与自然生态保护之间的矛盾。构建基于PSR模型的土地利用系统健康评价指标体系,并采用改进TOPSIS方法对三峡库区生态敏感区的典型区域—重庆市进行实证分析。结果表明:1)研究区土地利用系统健康综合分值整体呈现T型带状分布格局,可分为四个健康等级,即健康、临界健康、不健康、病态。2)渝东北、渝东南和重庆市西南片区部分地区因其土地生态系统脆弱敏感,土地利用风险性大和生态系统稳定性差,土地生态系统呈现病态和不健康状态,属于高风险-高压力区域;重庆市主城区环线区域因其属于城市核心拓展区和人类活动频繁区域,人口压力指数和土地利用压力指数较大,土地利用风险性较小,健康度较为良好,是低风险-中度压力区域。3)PSR模型能够较好地改变现有研究主要关注自然资源环境的状况,更准确地反映土地利用系统健康的各要素之间的关系和影响土地生态系统健康的关键因素,为三峡库区生态敏感区土地利用系统健康状态起到一定的预警作用。4)以改进TOPsis方法计算土地利用系统健康指数,消除了不同指标量纲的影响,并能充分利用原始数据的信息,能充分反映各方案之间的差距,客观真实的反映实际情况。5)为保障三峡库区生态敏感区土地利用系统的健康发展,应加强土地利用规划与调整,控制人类过度开发,维持生态系统正常功能。

The Three Gorges reservoir area forms an ecological barrier for the key sensitive areas of the middle and lower reaches of the Yangtze River. The ecological quality of a land use system is directly related to the overall benefits of the Three Gorges Project and to the ecological security of the middle and lower reaches of the Yangtze River. A health assessment of a land use system can effectively guide the rational land use and coordinate the contradiction between urban development and natural ecological protection. This study proposes a health evaluation index system of a land use system based on a PSR （pressure-state-response） model. Through the improved TOPSIS method, this research conducted an empirical study of Chongqing as a typical example of health assessment of a land use system in the ecologically sensitive area of the Three Gorges reservoir area. The results showed that： 1 ） The score of the Three Gorges reservoir area land use displayed a pattern of the ＂T＂ zonal distribution, which can be categorized as healthy, critical, unhealthy, and morbid. Morbid and unhealthy regions mainly cover the northeast, the southeast, and the southwest of Chongqing, which are in the state of stress and have higher health index. The critical and healthy regions are located mainly in the loop of main urban area in Chongqing. 2） The ecosystems in the northeast, southeast, and southwest regions of Chongqing, which are in morbid and unhealthy conditions, belong to high risk-high pressure areas, because of their fragile and unstable ecosystems and high risks of land use. The loop area in the Chongqing urban area, which is at low risk of land utilization and in relatively good condition, is in the low risk-moderate pressure area. To foster healthy development of land use in the ecologically sensitive area in the Three Gorges reservoir area, land use planning and adjustment should be strengthened, excessive human development of land should be restricted, and the ecosystem functioning should be maintained. 3） The PSR model as a means of analysis and unifying the natural resources, the environment, and social economy, not only emphasizes the health condition of ecosystems but also considers the impact of soeio-economic activities and their association in carrying out a comprehensive health evaluation of the land use system. PSR shifts the research focus to natural resources and environmental conditions. It fully characterizes the spatial characteristics of the land use system, accurately displays the relationship between various elements of a healthy land use system and the key factors affecting the ecosystem, and sets an early alarm for a land use system for the ecologically sensitive land in the Three Gorges reservoir area. 4） The improved TOPSIS method can make full use of original data, illustrate the reality, achieve a comprehensive diagnosis of the health condition of a land use system, and reveal the level of each indicator as well as the critical factors affecting the system. The method is effective and can be applied to other kinds of assessment with proper adjustments. 5） The evaluation index system based on the PSR model and the improved TOPSIS method can be applied to health assessment of a land use system. Both analysis methods can enhance the health condition of a land use system. This study can be a reference for further improvement of a health assessment of land use as well as for land use planning, management, and ecological protection