1995—2015年武汉城市湖泊景观生态安全格局演化

Study of urban lake landscape ecological security pattern evolution in Wuhan, 1995—2015

以1995、2005、2015年3期遥感影像为数据源,通过景观指数和GIS空间分析方法研究武汉中心城区湖泊系统景观格局的演化特征,进而构建湖泊景观生态安全评价模型,以揭示武汉中心城区湖泊系统景观生态安全格局演变规律,并探讨其驱动因素。研究结果表明:(1)近20年来武汉中心城区湖泊系统总面积呈现不断下降趋势,1995—2005年以年均2.4%的速率缩减了28.95 km^2,2005—2015年以年均1.8%的速率缩减了17.47 km^2。(2)研究期湖泊系统的斑块密度、分维数呈现不断降低趋势,这表明武汉中心城区湖泊破碎化程度在不断降低,湖泊形状趋于简化;而连接度呈现不断增加趋势,湖泊分布集聚趋势不断加强,空间结构趋于紧凑集中。(3)武汉城市湖泊系统总体景观生态安全呈现不断恶化趋势,而次级湖泊水系景观生态安全呈现不同的演化特征。城市建成区的迅速扩展、湖泊由农业生产对象转化为可利用发展用地、房地产事业成为支柱产业是湖泊系统遭填占最主要的动力,直接危害了其景观生态安全,而市民环境意识提高引发湖泊保护倡议和实践,对湖泊景观生态安全产生着积极影响。对湖泊景观生态安全格局演变特征及驱动因素的研究,可以为武汉制定行之有效的生态管理政策和环境治理措施提供重要支撑。

Using the remote sensing images of 1995, 2005, and 2015 as the data sources, this paper explored the temporal and spatial characteristics of the lake landscape pattern in the central district of Wuhan through selected landscape indices and the GIS spatial analysis method. Subsequently, the ecological security evaluation model of the lake landscape was established to reveal the temporal and spatial characteristics of the landscape ecological security pattern of the lake system. The results showed that:(1) In the past 20 years, the total area of the urban lake showed a decreasing trend. The lake area decreased by 28.95km^2at an annual average decreasing rate of 2.4% from 1995 to 2005, and 17.47km^2 at 1.8% in the time period 2005-2015.(2) The patch density and fractal dimension of the lake system both showed a decreasing trend, which indicated that the fragmentation of lakes was decreasing, and the shape was becoming simplified. The connectivity index showed a rising trend, which indicated that the lake space structure was becoming more compact.(3) The overall ecological safety of the urban lake system showed a deteriorating trend during the period 1995-2015. Each secondary lake system was influenced by a different degree of urbanization and human disturbance, thus the ecological security evolution of the secondary lake systems showed different characteristics. The rapid expansion of urban built-up areas, the transformation of lakes from agricultural production objects into usable development land, and the real estate industry as the pillar industries were the main driving forces for the lake system to be filled, directly endangering its landscape ecological security and raising public awareness of environmental protection through lake protection initiatives and practices that had a positive impact on the ecological security of the lake landscape. This research on the temporal and spatial characteristics of the lake landscape pattern and driving forces can provide an important support for Wuhan to formulate effective ecological management policies and environmental governance measures.