近15年南京都市圈区域绿地变化研究

Evolution of Regional Green Space in Nanjing Metropolitan Area in the Past 15 Years

以2003-2017年时间段为例,基于Landsat遥感影像,提取2003、2008、2013年和2017年4期区域绿地斑块,利用动态度、景观指数以及变化程度等方法,从规模与格局的角度对南京都市圈区域绿地的变化特征进行分析,并利用logistic回归模型对影响区域绿地变化的驱动因素进行估算。结果表明:1)2003-2017年,区域绿地面积不断减少,由2003年的6 090.33 km^(2)减少至2017年的5 577.92 km^(2)。其中2008年前,区域绿地规模变化较大,动态度为-1.55%,2008年后规模减速放缓,动态度为-0.09%;2)研究期内,区域绿地面积减少率位于70%~100%区间的单元数呈递减趋势,粗放式的区域绿地开发得到控制,但区域绿地总体稳定性不断下降。区域绿地面积增长率主要位于0~30%,面积总体增幅较小,增长率≥100%的单元分布离散,并呈现由山体周边向山体内部、沿江沿河处转移的特征;3)区域绿地的斑块密度、形状指数不断增加,斑块大小中位数、连接度以及聚集度总体下降。区域绿地在斑块特征上呈现小型化、破碎化,在空间分布上趋于离散的特征;4)高程、第二产业占比、公路里程等因素是影响南京都市圈区域绿地演变的重要驱动力。

The Nanjing Metropolitan Area is an important carrier for the integrated construction of the Yangtze River Delta in China, and also a core area for ecological environmental protection in the middle and lower reaches of the Yangtze River.Since the beginning of the new century, the urbanization process of the Nanjing Metropolitan Area has been rapidly advancing, and ecological security issues have become prominent.The analysis of the evolution characteristics of regional green space plays an important role in the construction of regional ecological security patterns.In this study, the time period of 2003-2017 was taken as an example, Landsat remote sensing images were used as the basic data, from which the regional green space patches in the years of 2003,2008,2013 and 2017 were extracted.The evolution characteristics of the regional green space in the Nanjing Metropolitan Area from the perspective of scale and pattern were analyzed by using dynamic degree, landscape index, and degree of change, and the driving factors affecting regional green space were estimated by logistic regression model.The results showed that 1) from 2003 to 2017,the area of regional green space decreased continuously, from 6 090.33 km^(2) in 2003 to 5 557.92 km^(2) in 2017.Before 2008,the scale of regional green space changed greatly, with a dynamic degree of-1.55%.After 2008,the scale decelerated and slowed down, with a dynamic degree of-0.09%.2) During the study period, the number of the units with a reduction rate of regional green space in the range of 70%-100% showed a decreasing trend.Extensive regional green space development was controlled, but the overall stability of regional green space continued to decline.The growth rate of regional green space was mainly at 0-30%,and the overall increase in the area was small.The units with the growth rate ≥100% were scattered and presented the characteristics of transferring from the periphery of the mountain to the inside of the mountain and along the river.3) The patch density and shape index of regional green space continued to increase, while the median patch size, connectivity, and aggregation generally decreased.Regional green space showed miniaturization and fragmentation in patch characteristics, and tended to be discrete in spatial distribution.4) Factors such as elevation, proportion of secondary industry, highway mileage and other factors were important driving forces affecting the evolution of regional green space in the Nanjing Metropolitan Area.