土地生态安全资源型关键地段识别——以长江三角洲无锡市为例

资源型关键地段对于维护和控制区域土地生态系统安全具有关键性作用。通过构建一套资源型关键地段识别的指标体系,在以次一级行政区为基本识别单元的基础上,识别出行政单元内地类斑块尺度的资源型关键地段。将无锡市划分为3级6类地段:关键地段、关键地段保护区、一般地段、干扰地段、干扰区以及交汇区,分别占全市总面积的19.70%、12.03%、39.62%、16.36%、12.28%和6.35%。关键地段斑块面积偏小、破碎化程度明显,空间分布不均匀,宜兴市境内关键地段占全市总量的85.26%;干扰地段斑块面积较大,空间分布不均,但相对集中,从面积和强度来看城区都较明显。干扰地段的形成受城镇空间发展影响明显;次一级行政区交汇区空间分布特征与形成原因不完全一致,空间分布也不均。城区50.48%、江阴40.91%、宜兴33.63%的关键地段保护区有被进一步破坏的可能。

Identification of Resource Major Portion of Land Ecosystem:A Case Study of Wuxi,the Yangtze River Delta Area

Resource major portion has the key function to the sustainability and the security of local land ecosystem, which is a critical part of local ecological networks. The main purpose of this paper is to promote an approach, which is suitable for the characteristics of land ecosystem of the Yangtze River Delta Area, with collected coarse ecological data and precise land use data to identify resource major portion. Firstly, a set of indices, 21 indicators, is proposed to identify the importance of different sub-municipal units within the objective, Wuxi municipal city. Then, a set of ecological contribution ratios of different land use is applied with GIS technology to identify the importance of different patches of land use within the sub-municipal units. Lastly, the total area of Wuxi municipal city is classified into six groups: resource major portion (RMP), RMP buffer, common zone, interference portion (IP), IP buffer, and overlapped zone of buffers (OB). The research result presents that these six groups of zones sharing the proportions of total area are 19.70%, 12.03%, 39.62%, 16.36%, 12.28% and 6.35% respectively. The patches of RMP are small in size and in an unbalanced spatial arrangement. 85.26% of all the RMP patches are in Yixing sub-municipal unit due to local physiogeographic factors and less human activities interference. The IP patches in average size are bigger and more spatially concentrative compared with those of RMP patches, especially for the IP patches in Binhu Built-up Area, the combination of seven sub-municipal units and the city centre of Wuxi municipal city. The spatial arrangement of IP patches has a close relation with those of the urban built-up areas and regional infrastructures. The characteristics of spatial arrangements of the OB patches in different sub-municipal units are different due to their different causes. At last, the authors recommend that there are 50.48% of the RMP buffer patches in Binhu Built-up Area, 40.91% in Jiangyin, and 33.63% in Yixing which have potential possibility of being interfered along with coming rapid urbanization.