Abstract: Ecological barrier in the Three Gorges Reservoir Area is the most important region in national ecological security system. Building regional ecological security pattern by landscape pattern optimization is a hot topic in research worldwide. By adjusting the components of landscape pattern, landscape pattern optimization aims to build pointpolylinepolygon ecological space network and enhance the integrity and connectivity of regional ecosystem. In this study, Jiangjin was chosen as a case study area for landscape pattern optimization. With the support of GIS, the map of landscape pattern was derived from the landuse map of 2014. The ecological sources were chosen by granularity inverse method. Ecological corridors and nodes were built by minimum cumulative resistance. The results showed that (1) 200 m was the best grain to connect the ecological source. There were 10 ecological sources (with a total area of 6.06×10⁴ hm²), 14 new ecological sources (with a total area of 0.01×10⁴ hm²), 22 ecological corridors and 24 ecological nodes; (2) The granularity inverse method could effectively overcome the subjectivity of choosing ecological sources; (3) minimum cumulative resistance could combine the ecological functions and processes and overcome the weakness of mathematical models that are hard to express spatial ecological processes. This study would provide scientific basis to landscape pattern optimization and the enhancement of ecological service value.

Key words: CROPGRO-Tomato, DSSAT, greenhouse, tomato, model, leave-one-out cross-validation.