基于MSPA和MCR模型的襄阳市生态网络变化研究

Variation of ecological network in Xiangyang City based on MSPA and MCR model

构建生态网络并对不同时期的生态网络变化趋势进行分析,这在生态环境修复方面具有重要的指向性意义.本研究以襄阳市为研究区,基于形态学空间分析(MSPA)方法和最小累积阻力(MCR)模型构建襄阳市1997—2017年的生态网络,结合整体连通性指数(IIC)、可能连通性指数(PC)、中介度指数(BC)和斑块节点度指数(Dg)对景观连接度进行分析,最后对不同时期的生态网络的变化进行分析评价.研究结果表明:1)生态源地斑块主要分布在襄阳市的西部山区和东南部丘陵地区,其他区域呈现零星分布,东西方向连接薄弱.2)2007—2017年,襄阳市东南部斑块受到明显蚕食,廊道数量下降,斑块破碎化程度较高.3)襄阳市林地面积逐年减少,提取的七类景观面积整体呈下降趋势,核心区面积从2007年开始,下降比例达5.62%.但IIC指数和PC指数仍保持在较良好的水平.4)网络评价指数从1997年到2017年呈下降趋势,说明襄阳市生态网络的复杂程度下降.研究结果以期为襄阳市生态环境修复研究提供科学依据.

Constructing an ecological network and analyzing the changing trends of the ecological network in different periods have important directional significance in the restoration of the ecological environment.Taking Xiangyang City as research area,we constructed an ecological network model of Xiangyang City from 1997 to 2017 based on morphological spatial analysis(MSPA)and minimum cumulative resistance(MCR),analysed the connectivity of the landscape with integral index of connectivity(IIC),possible connectivity index(PC),betweenness centrality index(BC)and patch node degree index(Dg),and finally analyzed and evaluated the changes of the ecological network in different periods.The research results are as follows.1)The ecological source patches are mainly distributed in the western mountain area and the southeastern hilly area of Xiangyang City,while other areas are scattered and the east-west connection is weak.2)From 2007 to 2017,the plaques in the southeast of Xiangyang City are obviously nibbled,the number of corridors decrease,and the degree of plaque fragmentation is higher than other years of the study period.3)Areas of the forest land of Xiangyang City will decrease gradually,and the overall area of seven types of landscape extracted shows a downward trend,with the core area decreasing by 82.2%since 2007.But the IIC index and PC index are still at a good level.4)The network evaluation index shows a downward trend from 1997 to 2017,indicating that the complexity of the ecological network in Xiangyang City decreases.The conclusions will guide the development of ecological environment remediation.