城市生态系统承载能力初步研究——以江苏省吴江市为例

城市作为一个复合生态系统,其承载能力的涵义与资源、环境承载力相比有很大差别。论文在探讨城市生态系统承载力内涵及各子系统相互关系的基础上,从承载力与压力指数的角度构建城市生态系统承载能力评价模型。以江苏省吴江市为例,建立承载力与压力指数评价的层次结构指标体系,应用评价模型对吴江市1990-2004年的城市生态系统承载水平进行评价。结果表明:吴江市在研究时段内生态系统承载能力与社会经济发展经历了由不协调到相对协调的过程。在选取的各分量指标中,环境容纳指数的平均贡献率高达38.68%,是提高城市生态系统承载力及抑制生态系统压力增长的重要因素;资源消耗的平均贡献率为54.45%,说明社会经济发展导致的资源消耗仍然是生态系统压力的主要来源。

A Preliminary Study on the Evaluation of Urban Ecosystem Carrying Capacity-A Case Study from Wujiang City, Jiangsu Province

The urban ecosystem is a social-economic-natural comprehensive system.the meaning of its carrying capacity is different from that of the resource and environment capacity.Scholars at home and abroad have studied the academic and practical aspects of ecosystem capacity and have acquired numerous research results.At present,the foci of the study are changing from the natural ecosystem to the complicated man-made ecosystem.In this paper,the theory of carrying capacity is reviewed and extended to the urban ecosystem.Based on the study of the urban ecosystem carrying capacity and the relationship between each subsystem,we built the quantitative model to evaluate the extent to which the urban ecosystem carrying capacity has reached from.The indexes of the model include carrying index,consisting of resource supply capacity(RS),environmental carrying capacity(EC),ecosystem reliance capacity(ER) and social-economic envelopment(SE) and pressure index which is consist of resource expenditure(RE) and surrounding pollution(SP).A case study in Wujiang city is described.Building the index system and employing the evaluation model,the complex carrying capacity of Wujiang city during 1990-2004 was evaluated.The result indicated that relationship between the ecosystem carrying capacity and the development of socio-economic system evolved from unbalanced to relatively balanced.Among each selected indicators,the average percentage of environmental carrying capacity(EC) index reached 38.68%.This indicator is the important factor which enhances the urban ecosystem carrying capacity and restrains the growth of the ecosystem pressure.The average percentage of resource expenditure(RE) index reached 54.45%,indicating that resource expenditure resulted from of socio-economic development is still the main cause of the ecosystem pressure.