长三角新建居住区景观绿化植物组成的相似性

Similarity of ornamental plant composition in new residential areas in Yangtze River Delta.

自然植被受城市化影响出现了不同程度的均质化,受人为影响更大的人工植物是否存在同样的问题值得关注。本研究以长三角10城市的45个居住区的景观绿化为对象,运用Jaccard指数,从居住区、城市、省份3个尺度水平上探讨了物种组成的相似性。结果表明:随着尺度水平增加,物种相似性显著增加,在城市和省份水平上Jaccard指数达0.45和0.50;随着城市间距离的增加,物种相似性逐渐减小;因数量少,乡土物种并未有效地降低城市间相似性,反而增加了省份间的相似性。表明目前长三角的居住区景观绿化物种单一,乡土物种尤为突出,呈现均质化倾向。

Natural vegetation is homogenized to some extent under the effects of urbanization. Whether the planted vegetation also has the same problem is an issue to be concerned with. By using Jaccard Index （JI） , the similarity of ornamental plant composition in 45 new residential areas of 10 cities in Yangtze River delta was investigated at the scales of residential area, city, and province. It was found that this similarity increased significantly along the gradient of residential area - city - province, with the JI being 0. 45 and 0. 50 at the scales of city and province, respectively, but decreased with increasing distance among cities. Owing to the small amounts, native plant species didn＇ t decrease the similarity among cities, but increased the similarity among provinces. These findings suggested that the ornamental plants in residential areas in Yangtze River delta were poor in species richness, especially of native plants, and presented homogenization trend.