A GIS-Based Landscape Pattern Optimization Approach for Lake Dianchi Watershed

Relationship between landscape pattern and ecological processes is a key issue of landscape ecology.By adjusting the components of landscape pattern,landscape pattern optimization aims to maximize the landscape eco-efficiency and enhance the ecosystem stability.The existing researches can not establish quantitative relationships between landscape pattern,functions and processes.The least-cost distance model describes the work or cost for the transformation from one landscape pattern to another with different resistance,and can interpret the relationships between landscape pattern and processes.In this study,the Lake Dianchi Watershed was chosen as a study area for landscape pattern optimization.With the supports of remote sensing(RS) and geographical information system(GIS),the landscape pattern was obtained through visual interpretation to the Landsat TM image of year 2008.The resistance was determined according to the valuation per unit area of ecosystem services.Taking the large water body as sources,the minimum cumulative resistance through the cost-distance model in ArcGIS was calculated.Combined with ecosystem services and spatial interactions of landscape types,a landscape functional network with sources,corridors and ecological function nodes was constructed.The optimization of landscape pattern strengthened the spatial connection of ecological network,maintained landscape stability,and improved the ecosystem services.The optimization measures and countermeasures for Lake Dianchi Watershed were proposed.For the high ecosystem services,important material support for regional economic and social development,and heavily vulnerability to human disturbance,it's very important to maintain and increase the area of natural water body.In order to maintain high landscape connectivity,the urban area corridor,forest ecological corridor and agricultural production corridor should be built in Lake Dianchi Watershed.Intervention strategies,such as maintenance of the corridor scale,establishment of buffer zones,strengthening the green vegetation,reduce the emission of pollutants,and so on,can increase the connectivity of the entire corridor.The nodes,which are critical to the ecological flow and connectivity of landscape,should be controlled strictly.This study,which optimized the landscape pattern for the Lake Dianchi Watershed through the least-cost model with combination of ecosystem services and spatial interactions of landscape types would provide scientific basis and reference to ecological planning and optimal layout of land use in basin scale.