Analyses of landscape change patterns that are based on elevation and slope can not only provide reasonable interpretations of landscape patterns but can also help to reveal evolutionary laws. However, landscape change patterns and their model in different landforms of the typical watershed in the Three Gorges Reservoir Area (TGRA) has not been quantified and assessed effectively. As a complex geographical unit, the ecological environment in the middle reach of the Yangtze River has experienced great changes due to the construction of the Three Gorges Project (TGP) and its associated human activities. Here, based mainly on a digital elevation model (DEM) and remotely sensed images from 1986, 2000, 2010, and 2017 and by using GIS technology, speeds/ trends of landscape change, the index of landscape type change intensity, landscape pattern indices, and landscape ecological security index, the spatial and temporal evolution characteristics of different elevations, slopes, and buffer landscape types were analyzed in typical watersheds, as well as an evolutionary model of the landscape pattern. The results indicated that (1) the landscape types along with the land classification and buffer zone that were influenced by the TGR construction have undergone a phased change, with the period 2000–2010 being the most dramatic period of landscape evolution during the impoundment period; (2) landscape type shifts from human-dominated farmland to nature-driven forestland and shrub-land as elevations, slopes and buffer distances increased. The landscape has shifted from diversity to relative homogeneity; (3) land types and buffer zones played essential roles in the landscape pattern index, which is reflected in the differences in landscape type indices for spatial extension and temporal characteristics. The results of this paper illustrate the spatial–temporal characteristics of various landscape types at three distinct stages in the construction of the TGR. These findings indicate that the landscape ecological security of the watershed is improving year by year. The follow-up development of the TGRA needs to consider the landscape change patterns of different landforms.

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Cultivated land fragmentation (CLF) has become the main obstacle restricting rural revitalization and agricultural modernization management in China, especially in southwest mountainous areas. And it’s of great significance to investigate the spatial-temporal evolution law of cultivated land as well as to facilitate regional food security and land management. Taking widely used areas of the Caotangxi River watershed as examples, based on landscape pattern principle, this paper constructs an evaluation system of CLF by landscape metrics. We firstly analyzed the temporal and spatial characteristics of cultivated landscape through the method of cultivated landscape gradient, calculated the value of CLF to reveal its evolution and spatial characteristics, explored the topographic gradient effects of CLF, and further summarized its modes. The results show that the area where arable land is concentrated are often comparatively crushed and distributed in the plain areas along the river banks. CLF in watersheds presented the overall improvement trend by the influence of natural conditions and China’s ecological policies. The overall level of CLF in the watershed is low during the whole study period, and the spatial evolution is uneven. The CLF displays pronounced regional divergence patterns in space, and the value of CLF is comparatively high in terrain Grade 2 and 3, which is the pivotal area for alleviating the fragmentation in the subsequent work. These findings imply that the differences of characteristics of CLF with terrain gradient must be considered in the formulation of targeted policies for land consolidation in the watershed.