ABSTRACT
Human disturbance in the landscape lead to dramatic changes in the spatial structure of landscape patterns. This paper takes the Chongqing Three Gorges Reservoir area of China as case study to carry out gradient change analysis of the landscape pattern. Firstly, the coupled inflection point analysis, information loss method, and principal component analysis are used to determine the optimal grain size in a landscape gradient analysis. Secondly, the multidirectional gradient transect method is selected to analyze the law of landscape gradient change and the change of the landscape index. Finally, we analyzed various landscapes at the type level and obtained the distributions of the landscape types. The research highlights the gradient characteristics and landscape structure responses of typical transects of landscape subdivision types. The main results are as follows: (1) The optimal grain size of gradient analysis is 50 m. The patch density, patch shape complexity, and land use abundance of transects from the head to the tail of the reservoir increase. (2) At the landscape level, low mountain areas are more strongly blocked, and landscape connectivity reaches a minimum. At the type level, the landscape shape in the urban-rural interface zone is more complex. (3) Various landscape types are regularly ordered and form the gradient of "urban-agricultural-natural."
