基于CVOR和电路理论的讨赖河流域生态安全评价及生态格局优化

生态安全格局优化是实现区域生态安全、维持区域可持续发展的重要途径。以生态系统服务与健康共同构建"贡献力-活力-组织力-恢复力"（CVOR）的生态安全评价体系,对2000和2015年讨赖河流域生态安全进行评估,识别生态源地,提取最小成本路径。基于电路理论连通度模型构建次优生态廊道,识别障碍点,基于生态源地、最小成本廊道、次优廊道、障碍点识别结果,构建并优化生态安全格局。结果表明：2000和2015年讨赖河流域低度安全等级区分别占流域总面积的63.68%、61.25%,高安全区和较高安全区仅占总面积的13.93%、15.80%。从空间分布来看,生态安全状况差异显著,呈现南高北低的分布格局。生态源地面积3165.41 km²,破碎度高,主要分布于流域南部山区及中部绿洲农业区。最小成本路径共1122条,共长3468.15 km,较大阻力廊道有242条。将流域生态格局优化分区划分为生态稳定区、生态发展区和重点保护区。提出流域生态安全格局的优化策略,为干旱区内陆河流域开发建设和生态保护提供参考。

Ecological security evaluation and ecological pattern optimization in Taolai River Basin based on CVOR and circuit theory

The optimization of ecological security pattern is an important approach to achieve regionally ecological security and maintain regionally sustainable development. The Taolai River basin is a typically arid inland river basin with fragile and sensitively ecological background and prominently ecological problems. According to the ecological environment situation of the study area, the evaluation framework of ecosystem services and ecosystem health was developed to assess the ecological security of the basin in 2000 and 2015 based on "contribution, vigor, organization, and resilience" model. On this basis, the ecological sources were identified. With the help of Linkage Mapper tool, the least cost corridors were extracted. Sub-optimal corridors were constructed based on the Circuitscape software. In addition, barriers were identified by using Barrier Mapper tool. In order to provide references for the development and construction of arid areas and ecological protection, the optimization strategies of ecological security pattern in the basin were put forward. The results showed that:(1) on the whole, the ecological security of the basin was not optimistic. In terms of area, in 2000 and 2015, the low security area accounted for 63.68% and 61.25% of the total area, respectively, while the high level security areas and higher level security areas accounted for only 13.93% and 15.80%. From the perspective of spatial distribution, there were significant differences in the ecological security. The south and the central regions were higher than the north region. (2) We constructed and optimized the ecological security pattern based on the identification results of the ecological source, the least cost corridor, the sub-optimal corridor, and the barrier. The ecological sources were mainly distributed in the mountain of Sunan Yugur Autonomous County in the south of the basin and the agricultural areas of Jinta County, Jiayuguan City and Suzhou District in the middle areas of the basin. A total of 1122 least cost paths with a total length of 3468.15 km were generated among the ecological sources. There were 242 corridors distributed among the relatively far away source areas with higher resistance, which separated by higher resistance, such as bare rock and bare land. (3) The optimized division of the ecological pattern of the basin was divided into ecologically stable areas, ecological development areas and key protected areas. The optimization strategy of the ecological security pattern of the basin is proposed to provide a reference for the ecological protection, development and construction of the arid inland river basin.