武汉市绿色廊道景观格局

绿色廊道作为城市关键的景观结构要素,在维持城市生物多样性,改善城市生态环境,调节小气候等方面发挥着重要的作用.以武汉市建成区为例,探讨城市绿色廊道景观格局定量研究的方法,使其充分发挥生态功能,从而指导城市绿色廊道的规划与建设.利用GIS处理基础资料,对城市廊道系统进行提取与分类,生成拓扑关系图,并计算景观格局指标参数.从廊道景观的构成和绿色廊道的网络结构两方面详细分析了武汉市建成区各行政区内各类型绿色廊道的景观格局.结果表明：在武汉市建成区内,灰色廊道最长,占廊道总长的63.53﹪;绿色廊道极其缺乏,总密度仅为2.63 km/km^2;在绿色廊道中,绿色道路廊道最长,占绿色廊道总长的60.29﹪.绿色廊道普遍较窄,绿带的长度不到其它类型绿色廊道总长的1/3;绿色道路廊道最窄,少数达20 m.绿色铁路廊道面积较小,为1.68 km^2,其它类型的绿色廊道面积相当,各占总面积的30﹪左右;3个行政区中,武昌的绿色廊道长度最长,面积最大.绿色廊道网络线点率、环通度及连通度均不高,网络结构简单,不利于城市生物多样性的维持.绿色道路廊道网络结构相对最复杂;绿带的网络连通性最差,没有回路存在;武昌的绿色河流廊道、绿带以及绿色铁路廊道网络结构最复杂,绿色道路廊道网络最复杂的是汉口.武汉市绿色廊道的建设,应注重长度和宽度的增加,提高绿带的比例;重视各类型绿色廊道及其在各行政区间的均匀分布;减少绿色廊道的断开区,增加网络连通性;使其走向与城市主导风向一致,兼顾通风走廊的功能.

The landscape patterns of the green corridors in Wuhan City, China

As critical urban landscape components,the green corridors play significant roles in maintaining biological diversity,improving ecological environment and regulating microclimate.This paper discussed the quantitative study method for the landscape patterns of urban green corridors taking the built-up area of Wuhan as a case,which can benefit the urban planning and construction to improve the ecological functions of green corridors.GIS technology was employed to process the basic data,distill and classify Wuhan's corridors,to obtain topological framework maps and to calculate the landscape pattern indices.The landscape patterns of each type of green corridors in each of the three districts have been analyzed from two aspects,the landscape composition of the corridors and the structure of the green network.The results indicate:(1)In the built-up area in Wuhan,the gray corridors,which account for 63.53 percent of the total corridor length,are the longest.The green corridors are scarce and their overall density is 2.63 km/km~2.Among the green corridors,the green road corridors are the longest and they are 60.29 percent in the whole green corridors.(2)Most Wuhan's green corridors are narrow.The green belts are less than one third of the other green corridors.The narrowest is the green road corridor,which is usually less than 20 m.(3)Except for the green railway corridors,with a small area of 1.68 km~2,the other types' areas are close with about 30% of the total area for each type.Among three districts,the green corridors in Wuhan are the longest and the largest.(4)Ratio of line to node,circuitry and connectivity are small and the green network is simple in Wuhan.The network of the green road corridors is the most complicated and the green belts' connectivity is the lowest.The network structures of the green river corridors,the green belts and the green railway corridors in Wuchang district are the most complicated,however,the network structure of the green road corridors in Hankou district is the most complicated.As to the construction of the green corridors in Wuhan,some suggestions should be noticed.The length and the width of the green corridors should be increased.More green belts ought to be built.All types of green corridors should be distributed evenly among the districts.The disconnection of the network should be decreased and the connectivity should be increased.As the ventilation corridors,the green corridors' orientation should be parallel to the dominant wind direction.