基于GIS的高原湖泊流域生态安全格局构建及优化研究——以星云湖流域为例

以星云湖流域自然人文环境特征、主要生态环境问题为出发点,结合景观生态学原理方法、熵值法和GIS空间分析技术,实现星云湖流域生态安全的空间分异格局及优化。选取海拔高程、坡度、土壤侵蚀强度、地质灾害易发性、土地覆被(利用方式和植被覆盖度)、人口密度、距自然保护区距离、距离建设用地和距水源距离等因素为阻力因子叠加生成综合阻力要素,根据GIS空间成本距离分析原理,引用最小累积阻力模型识别构建流域生态廊道和生态节点,进一步规划优化流域生态功能网络的结构和功能。研究表明:(1)从各安全等级面积比例和平均生态安全指数角度,星云湖流域中度安全占流域总面积的45.81%,高度安全为25.24%,较低安全为21.05%,不安全占7.9%,平均生态安全指数为2.95,流域生态安全总体处于中度安全,生态系统健康一般,但部分地区生态安全性较低,主要分布在南部、东部和北部地区,应重视这些区域的生态保护和建设;同时,坡度、水土流失因子和水资源(自然环境要素)、土地利用格局和距离建设用地(人类活动干扰要素)等因素是流域生态安全格局形成的主要因子;(2)识别规划了中枢生态源、核心型生态源斑块、一般生态源、多种级别的生态廊道和生态节点或战略点等构成的具有结构性和层次性的流域生态安全网络格局,对不同层次和结构的生态源、生态廊道和生态节点或战略点进行针对性建设保护,将有效提升流域生态系统的功能价值性和系统的完整性,进而加强流域生态稳定安全。

STUDY OF CONSTRUCTION AND OPTIMIZATION OF ECOLOGICAL SECURITY PATTERN OF LAKE BASIN IN PLATEAU BASED ON GIS——A CASE STUDY OF XINGYUN LAKE BASIN

Based on the characteristics of natural and cultural environments of Xingyun Lake Basin,the main ecological environment problems,the ecological safety spatial pattern and its optimization in Xingyun Lake basin were analyzed using the principle and method of landscape ecology,entropy method and GIS spatial analysis technology.The factors such as altitude,slope,soil erosion intensity,susceptibility of geological hazards,land cover(use and vegetation coverage),population density,distance from the natural ecological protection zone,construction land and the water source were selected as the resistance factor to generate comprehensive resistance element.Basin ecological corridor and ecological node were established to optimize the structure and function of ecological network in basin by using the minimum cumulative resistance model (MRC) on theory of GIS spatial cost distance.The results showed that:(1) from the perspective of the area ratio and the average index of ecological security,the area of moderate level security accounting for 45.81％,the area of high level of security accounting for 25.24％,the area of Lower level of security accounting for 21.05％,the area of Low level of security accounting for 7.9％ of study area.Average ecological safety index in Xingyun Lake basin was 2.95,the ecological security and ecosystem health as a whole was in moderate level.But the ecological level of security is low in some areas else that mainly distributed in the southern,Eastern and northern regions.The factors such as slope,water resource environment,water and soil loss,and disturbance factors of human activities such as Land use pattern,distance from construction land are the main factors to form the ecological security pattern of the basin.(2) An ecological security network pattern with structured and hierarchical consists of Central Ecological sources,core ecological source and general ecological source,multiple levels ecological corridor and ecological nodes was established.The ecological corridors and ecological nodes in different levels and ecological source structure were discriminatively constructed and protected that will effectively enhance the integrity and function value of basin ecosystem,and then it will be helpful to enhance stability and security of basin ecology.