基于长时间序列遥感数据的深圳景观连通性动态变化研究

Dynamic changes in the landscape connectivity in Shenzhen City determined based on the long time series of remote sensing data

在过去30 a间深圳市的土地利用经历了从剧烈变化到近于饱和的过程。文章基于1988—2015年10期深圳市土地覆盖/利用数据,结合形态学空间格局分析(morphological spatial pattern analysis,MSPA)和图论模型定量分析了深圳生态用地的景观连通性。结果表明,生态用地中耕地在深圳城市化不同阶段均为城市用地扩张的主要土地来源,2005年后林地作为城市土地来源的比例显著提升。景观连通性方面,1988—2015年间深圳市生态用地等效连通面积(equivalent connected area,ECA)减少了1175.4 km^(2),网络连接度(degree of network connectivity,DOC)降低了43.51%。自深圳2005年划定基本生态控制线以来,城市生境退化趋势明显放缓,但生态用地ECA依然以每年11.9 km 2的速度被逐渐侵蚀。斑块重要性分析表明,阳台山和塘朗山等区域是目前维持深圳市现有景观连通性的关键枢纽节点,需加大保护力度。

In the past 30 years,the land use in Shenzhen City has changed dramatically until it is almost saturated now.Using the morphological spatial pattern analysis(MSPA)and the graph theory,this study quantitatively analyzed the landscape connectivity of ecological land in Shenzhen based on ten phases of remote sensing images for land cover or use from 1988 to 2015.The results show that the cultivated land was the main land source in various periods of Shenzhen’s rapid urbanization,while the proportion of forest land used for urban development had risen since 2005.For Shenzhen’s landscape connectivity from 1988 to 2015,the equivalent connected area(ECA)of the ecological land decreased by 1175.4 km^(2),and the degree of network connectivity(DOC)decreased by 43.51%.Since the delineation of Shenzhen’s basic ecological control boundary in 2005,the pace of urban habitat degradation has slowed down but the ECA of the ecological land had still been gradually eroded at a rate of 11.9 km 2 per year.The analysis of the importance of ecological patches shows that areas like the Yangtai Mountain and Tanglang Mountain are key ecological nodes for landscape connectivity and should be protected with greater efforts.