Abstract:

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 the framework of landscape patterns in karst area of Chongqing, and to determine the factors to drive the changes in landscape patterns. The results showed that landscape types presented unevenness tendencies, and several dominated preferably. Landscape mosaic patches had complex 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.

Key words: Chongqing, drivers, environmental heterogeneity, karst area, landscape patterns