景观空间异质性及城市化关联——以江苏省沿江地区为例

空间异质性是揭示地理现象空间分异规律的重要标志.基于高分辨率卫星遥感影像数据,利用景观生态指数和统计学方法,构建景观空间异质性综合模型,定量测度了江苏省沿江地区景观空间异质性特征及城市化关联,并基于二者的相关性将研究区域划分为6个异质性梯度区,提出了应对城市化干扰的景观空间协调对策.结果表明:景观空间异质性综合模型是对景观斑块结构、形态、数量3个组分特征的反映,是揭示景观连通性、稳定性和破碎化的重要依据；景观空间异质性与3个城市化参数之间存在显著的正相关,城镇空间扩张模式和城镇人口的集聚强度对景观空间异质性影响较大；景观空间异质性梯度分异与区域开发强度、开发时序存在显著的耦合关系；同时,面对城市化的干扰,应该实施保护生态景观空间、减少建设空间与其它景观的接触概率和实施差别化的城市化战略等政策协调城市化发展与景观生态保护之间的矛盾.

Landscape spatial heterogeneity is associated with urbanization: an example from Yangtze River in Jiangsu Province

Spatial heterogeneity is an important concept in ecology and geography.Landscape spatial heterogeneity is defined as the spatial variation of land use patch types, composition and properties. This has important consequences for landscape connectivity, stability and fragmentation and can determine the functions and processes of ecosystems. Landscape spatial heterogeneity emerges from the interaction between human activities and natural ecosystem dynamics. However, with social and economic development as well as human population growth, the human influence is growing stronger. Analysis of spatial heterogeneity is helpful as it can reveal spatial geographical differentiation. Using high-resolution satellite remote sensing data, along with landscape ecological index methods and statistics, a landscape spatial heterogeneity model was constructed. The model was used to quantitatively estimate landscape spatial heterogeneity characteristics and urban connections along the Yangtze River in Jiangsu Province, and to divide the study area into six regions along a heterogeneity gradient. The results showed that the landscape spatial heterogeneity model provides a valid and comprehensive representation of three characteristics of the landscape-patch structure, shape and quantity-which determine connectivity and stability. There was a significant positive correlation between the landscape spatial heterogeneity index and three urban parameters. The correlation coefficient between the landscape spatial heterogeneity index and concentration intensity of the urban population was 0.854. The correlation coefficient between the landscape spatial heterogeneity index and urban spatial expansion pattern was 0.672. Thus, the urban spatial expansion pattern and concentration intensity of the urban population had strong effects on landscape spatial heterogeneity. There was a significant simultaneous increase between landscape spatial heterogeneity and three urban parameters, which indicated that urbanization has a variable effect on landscape spatial heterogeneity. There were couplings among landscape heterogeneity gradient differentiation, regional development strength and development sequence. Areas of high heterogeneity, such as Nanjing, Suzhou and Wuxi, are the developed regions with the greatest pace of development in Jiangsu Province, and even China. Areas of low heterogeneity, such as Xinghua, Haian, Ruzhou, are distributed in the middle of Jiangsu Province where the level of urbanization is lower and the economy develops at a slower pace. These findings help understand the relationship between economic development and environmental degradation for this area. It is proposed that landscape protection, reduction of construction land and other landscape contact probabilities, and the implementation of differentiated strategies for the city could reduce the conflict between urban development and environmental protection. To preserve the ecological landscape, we should focus on land protection and corridor construction to enhance connectivity. We should also protect forest parks, wetlands and water conservation areas to reduce landscape fragmentation and maintain biodiversity. To reduce construction land and other landscape contact probabilities, we should implement smart growth strategies to prevent further urban sprawl when re-developing urban land-use patterns.