天祝草原景观格局分析及景观利用格局优化

Landscape Pattern Analysis and Optimized Utilization in Tianzhu Grassland based on RS and GIS Technology

运用遥感、GIS技术与景观生态学的研究方法相结合,以天祝草原为研究对象,以Landsat/ETM+影像为基本信息源,通过计算景观多样性指数、优势度指数、破碎度指数、分维数等指标,从景观斑块特征、景观形状及景观的空间分布等方面对研究区的景观格局进行了分析,得出如下结论:草地与林地构成了研究区景观的主体,草地是整个景观的基质;研究区景观格局呈现出明显的垂直分布特征,从山谷到山顶依次按照城乡居民及工矿地—耕地—草地—林地—未利用地的分布顺序。据此分析,以物种保护为目标种,利用最小阻力表面(MCR)和耗费表面模型,借助表面扩散技术,构建了生态上较为安全的格局优化途径。格局优化法在水平关联的方向上为景观规划指出了一条生态学途径,是对传统的以适宜性评价为主导的生态规划方法的有益补充。

Based on RS and GIS technology and landscape ecology theory, landscape patterns of Tianzhu grassland were analyzed in terms of landscape＇s patch characters, shape, and spatial distribution which is expressed in diversity indexes, predominance, fragmentation, evenness by using TM/ETM ＋ image in 2002. The results showed that grassland area occupied 45.45 percent of the total land cover and the area of forestland occupied 31.53 percent of the total. Grassland and forestland are main landscape types in the study area. The landscape types presented an evident characteristic of vertical distribution. The landscape types are ranged from valley to hilltop by order of residential land, industrial land, cultivated land, grassland, forestland, and unused land. Based on objective of species conservation and MCR model, we designed more secure approach of landscape patterns. The area of cross-buffer zone of grassland and forestland in class one is 2 422.15 hectare, and the perimeter of the zone is 19 882.02km. The area of buffer zone in class two is 879.79 hectare, and the perimeter of the zone is 10 552.96km. Using optimization method, we analyzed the relationship of landscape pattern and landscape＇ s spatial structure. These will not only provide decision-maker a support for policy formulation on environment protection and bio-diversity protection and ecological rehabilitation, but also provide reference to other similar areas in land use optimization and ecological recovering. The results indicated that the ecology in study area is in safe condition generally, but unsafe area still occupies a fourth of the total. Therefore, a great attention must be paid to ecological safety in the study area. The method provides a good ecological route and also it is a good supplement to the conventional landscape programming which based on suitability evaluation. Under guidance of the landscape ecology principles and methods, a series of problems involving landscape use and optimization could be solved.