黔中喀斯特山地城市景观稳定性评价与特征分析

城市景观稳定性是对城市生态环境进行分析和评价的基础,对城市景观生态安全格局和景观可持续性具有十分重要的意义。以典型喀斯特山地城市贵阳市为研究对象,以2008年、2013年和2017年景观类型为主要数据。运用蔓延度指数、斑块密度和总边缘对比度构建景观稳定性评价模型,在分析2008-2017年景观格局变化状况的基础上评价景观稳定性时空特征。并运用探索性空间数据分析方法揭示贵阳市景观稳定性时空演变规律和冷热点特征。结果表明:(1)2008-2017年贵阳市景观格局发生剧烈变化,耕地面积大幅减少,林地和建设用地面积持续增加,景观破碎化程度加剧,但破碎化趋势有所减缓。(2)10年间,贵阳市景观稳定性水平整体较低,以不稳定和较不稳定为主,表现出"先降低、后提高,总体略有降低"的趋势。(3)贵阳市景观稳定性的空间分布与演变具有明显空间聚集效应,全局Moran''s I指数介于0.2008-0.4005之间,但聚集趋势呈"总体减弱,小幅提高"的特征;此外,景观稳定性热点区主要集中在城镇建设用地或林地斑块相对集中连片、完整的区域。研究结果可为喀斯特山地城市景观空间格局优化、生态安全网络格局构建和生态文明城市建设提供重要的科学依据。

Evaluation and characteristic analysis of urban landscape stability in karst mountainous cities in the central Guizhou Province

Urban landscape stability is the basis for analysis and evaluation of urban ecological environment, and is of great significance to the patterns of urban landscape ecological security and landscape sustainability. This study takes Guiyang City, a typical karst mountain city, as the research object. Landscape types in 2008, 2013 and 2017 were used as the main data. The spatio-temporal characteristics of landscape stability were evaluated by using Contagion Index, Patch Density Index and Total Edge Contrast Index to construct an evaluation model of landscape stability. The spatial-temporal evolution of landscape stability and characteristics of hot spots in Guiyang City were revealed by exploratory spatial data analysis. The results showed that:(1) the landscape pattern of Guiyang City changed dramatically from 2008 to 2017. The area of cultivated land decreased significantly, the area of forest land and construction land increased continuously. Furthermore, the degree of landscape fragmentation intensified, but the trend of landscape fragmentation slowed down. (2) From 2008 to 2017, the overall landscape stability level of Guiyang was relatively low, mainly unstable and relatively unstable, showing a trend of "decreasing first, then increasing, and generally decreasing slightly". (3) The spatial distribution and evolution of landscape stability in Guiyang had obviously spatial aggregation effect, and the Global Moran''s I index was between 0.2008 and 0.4005, but the aggregation trend was "overall weakening, slightly increasing". In addition, the hot spots of landscape stability were mainly concentrated in the contiguous and intact areas of urban construction land or forest patches. Therefore, based on the fragmentation of the natural landscape background of karst mountain cities, in the coupling period of rapid urbanization and ecological civilization construction, in order to improve the stability level of karst mountain cities'' landscape and enhance the ability of landscape anti-interference. In the process of urbanization construction, ecological protection and restoration in the future, the relative integrity of landscape patches and intensive construction land and cultivated land should be strengthened. Repair the broken patches, strengthen the connectivity of ecological land patches, improve the degree of landscape sprawl or aggregation, slow down the degree of landscape fragmentation, and improve the level of landscape stability. It lays a stable landscape foundation for the construction of urban landscape ecological security and ecological network pattern in karst mountain areas, thus promoting the coordination and balance of ecology and development in karst mountain areas. The results can provide an important scientific basis for the optimization of urban landscape spatial pattern, the construction of ecological security network pattern and the construction of ecological civilization city in karst mountainous cities.