多风险源驱动下的土地生态风险评价——以江苏省射阳县为例

我国正处于快速城镇化阶段,土地利用格局变化改变了土地生态系统的结构和功能,造成土地生态风险的进一步加剧和风险来源的多样化。论文根据风险来源、风险受体和风险效应的作用关系,提出了基于多源风险的发生概率、风险受体的抵御和自我恢复能力及其暴露于风险环境下可能发生的损失的土地生态风险表征方法。选取适当的指标计算得出风险来源指数、自然系统损失度和恢复力、社会系统损失度和恢复力、自然风险指数、社会风险指数和综合风险指数。论文以江苏射阳县为例开展实证研究,结果表明：射阳县城所在地社会风险指数最高,东部沿海丹顶鹤自然保护区自然风险指数最高,需要加强对这些地区的限制建设和生态保护。县城周边以及中东部大片区域综合风险指数较低,可以进行进一步的城镇发展和土地开发利用。论文提出的土地生态风险评价方法可为土地利用的风险评估提供方法参考,研究结论可为射阳新型城镇化发展与生态环境保护提供决策参考。

Assessment of Land Ecological Risks Driven by Multi-sources: A Case Study of Sheyang County,Jiangsu Province

Land ecosystem including nature subsystem and social subsystem is an important part of global terrestrial ecosystem, which supports human beings’ livelihood. With rapid urbanization and the social progress, the land-use of China transformed significantly and this process changed the structure and function of land ecosystem. Those changes led to further degradation of land ecosystem driven by multiple risk sources. Thus,it is of great significance to evaluate land ecological risks in order to guide the exploitation of land resource. We proposed a method to assess land ecological risks by combining the occurrence probabilities of multi-sources risks, the resistance and resilience of land ecosystem and possible damages when land ecosystem is exposed to risky environment. This paper quantified and spatialized the land system ecological risks using tools in geography information system. This paper took Sheyang County of Jiangsu Province for example. Based on the practical condition of Sheyang and the feasibility of data acquisition, several targets were selected to calculate the land ecological risk source index, nature system resilience index and damage index, social system reliance index and damage index, nature system risk index, social system risk index and complex system risk index. The result showed that: 1) The soil pollution, soil sealing and water pollution play an important role in land ecosystem risk source index. The land ecosystem risk source index is much higher in urban area than in rural area, which shows the risk sources index is closely related to the urbanization progress and the socioeconomic development. Urbanization progress brings more risk sources. 2) The town center of Sheyang is the region with the highest social system risks, while the region of the highest nature system risk locates in the nature reserve of eastern Sheyang which is bounded by the Huanghai Sea, therefore. In these two regions, more attention should be paid to ecological protection and restricted construction. 3) When it comes to the complex system risk index, the highest value appears in the nature reserve near Huanghai Sea, being less than 0.5 in the core zone of the nature reserve. The town center also shows relatively high value of the complex system risk index. Lower values distribute in large areas in the east of Sheyang and around the town center. It is suitable for urban expansion and land development in these regions. Correspondingly, it needs to restrict the expansion of the nature reserve and the town center. According to the research results, this paper proposed diversified land ecology policies in different regions of Sheyang, which can provide decision-makings for urbanization and ecological environment protection in Sheyang. It is proved by the research results that the assessment model of land ecological risks presented in this paper has high precision and can express regional land ecological conditions very well. This model can provide a reference for further work of quantifying land ecological risks.