重庆岩溶区景观格局特征分析

The Characteristics of Landscape Patterns in Karst Area of Chongqing, China

借用景观空间格局指数分析重庆岩溶区景观格局框架,辨识影响景观格局的驱动因素。结果表明:重庆岩溶区景观分布不均匀,少数几类控制着整体景观。嵌块体几何形状较复杂,被分割程度较低,破碎化现象不明显,空间异质化程度低。各亚区景观多样性,均处于最大值2.81的中间段,有一种或少数几种景观类型起支配地位。人工干扰程度和丰富度依I、II和III区地势降低的态势而增加,异质化程度、不均匀性和优势度则呈相反趋势。分维数差异不明显,形状指数变幅较大,不同区景观嵌块体几何形状较复杂且差异悬殊。森林景观嵌块体密度和分离度按I、II和III区的顺序依次增加,耕地、园地和居民工矿用地则分别依次减少。边界密度除了III区水域为63.03外,其余都在1.82￣9.14之间。景观整体特征I和II区相似,而与III区存在显著差异。内地质作用在大的环境背景下控制着岩溶区景观格局特征的基本框架,外营动力在较短时空尺度上决定岩溶区景观格局特征的纵深态势。研究可为区域岩溶景观格局调控、景观规划和生态经济的持续发展等宏观决策提供科学依据和理论支撑,为岩溶区区域生态安全评价积累数据基础。

There is an even poorer understanding of the characteristics of landscape in southwestern karst area, China, particularly in Chongqing. The objective of this paper was to measure geological shape, lower isolation, unobvious fragment, and fragmentation. And further their spatial heterogeneities were much lower. The value of landscape diversity all distributed at average position of maximum landscape diversity 2.81 in each karst subarea of Chongqing. Similarly, one or several landscape types controlled landscape patterns of each subarea. Disturbance index and relative richness were the increasing tendencies associating with the decrease of landform along the rank of Ⅰ, Ⅱ and Ⅲ, while the reverse results occurred in heterogeneity, unevenness and dominance. There was significantly difference between fractal dimensions, and higher fluctuation between shape indexes in each subarea. Thus, the geological shape among different landscape mosaic patches was very complex, and the differences between them were very pronounced. The density and isolation of landscape mosaic patches increased along the rank of Ⅰ, Ⅱ and Ⅲ, while the contrary results were detected in cropland, orchard land and residential and mining land. Except for water body with 63.03 edge density in Ⅲ, the rest all ranged from 1.82 to 9.14. Similar landscape characteristics were observed between Ⅰ and Ⅱ, but the obvious differences were witnessed, when they compared with that of Ⅲ. In karst area, internal geological function, under the big environmental background, controls the basic trends and processes of landscape patterns, while external dynamics, at short-term spatial-temporal scale, has become a major force in shaping the environment. This study will be useful to supply fine ground and knowledge for establishing appropriate landscape practices and evaluating ecological security in karst area.