赵娟娟¹欧阳志云^1*郑 华¹徐卫华¹王效科¹倪永明²

1 (中国科学院生态环境研究中心城市与区域生态国家重点实验室, 北京 100085)

2 (北京自然博物馆, 北京 100050)

摘要: 大量种植外来植物已成为我国城市绿地建设的一个主要问题。开展城市建成区外来植物种类构成的研究 , 可为城市植物的多样性保护及绿地的科学设计提供重要依据。本文采用分层随机抽样法 , 调查了北京市五环以内的乔木样地1,050个, 灌木样地797个, 草本样地2,228个, 共记录外来维管束植物 80科208属324种。统计分析的结果显示, 北京建成区植物的外来种比例高达 53%, 其中64%的国外外来种来自美洲和亚洲; 不同生活型植物中以常绿植物和藤本植物的外来种比例最高。根据其盖度、密度和频度值, 北京建成区主要外来种有野牛草(Buchloe dactyloides)、凹头苋 (Amaranthus blitum)、虎尾草 (Chloris virgata)、大叶黄杨 (Euonymus japonicus)、圆柏 (Sabina chinensis)、刺槐 (Robinia pseudoacacia)、白皮松 (Pinus bungeana)等15种, 部分外来种已成为建成区绿地的优势植物。外来种比例最高的绿地类型是观赏性要求较高的公共设施绿地。外来植物属的区系地理分布很广泛 , 与北京建成区的乡土植物相比 , 热带成分的比例增加而温带成分的比例降低。北京建成区外来植物的种类构成特点反映了城市建成区为了增加观赏植物种类而人为引入大量外来植物所造成的影响。

关键词: 城市植物, 外来植物, 城市绿地, 生活型, 优势植物, 区系地理分布

Species composition of alien plants in the built-up area of Beijing

Abstract: The widely-used practice of planting alien plant species has become a major concern in Chinese urban anagement. It is imperative to investigate the composition of alien plant species in urban areas for plant diversity protection and green space management. In this study, we investigated 1050 tree plots, 797 shrub plots and 2,228 herbaceous plots based on stratified random selection, within the fifth ring road area of Beijing. The results revealed the following: (1) There were 324 plant species from 208 genera and 80 fami­lies recorded in the study area; (2) The percentage of alien plants in the built-up area of Beijing was as high as 53%, and 64% of the alien species originated from America and Asia, and evergreens and lianas had the highest percentage of alien species among the various life forms present; (3) The major alien plant species in terms of high coverage, density and occurrence were Buchloe dactyloides, Amaranthus blitum, Chloris vir­gata, Euonymus japonicus, Sabina chinensis, Robinia pseudoacacia and Pinus bungeana. Some of these spe­cies had become the dominant plant species in the green spaces of the study area; (4) The percentage of alien plant species in institutional green spaces was higher than other green spaces; (5) The chorological spectra of the alien plant genera were wide; and (6) Compared to native species, the percentages of tropical elements were higher and the percentages of temperate elements were lower in the study area. Our results highlighted the changes in plant species composition inBeijingcaused by intensive introduction of alien plants with aes­thetic values.

 Key words: urban plants, alien plants, urban green space, life forms, dominant species, chorological spectra

生物多样性 2010, 18 (1): 19–28