都柏林城市中心公园树木组成结构及多样性研究

Study on the Tree Composition and Diversity in the Central Parks of Dublin

为更好地了解都柏林市中心区域公园树木组成结构及多样性,对分布于都柏林市区中心的圣斯蒂芬斯绿地、梅里恩广场、伊菲花园和菲茨威廉广场4个公园进行实地调查,利用重要值、多样性指数、相似性系数等参数对所获数据进行分析。结果表明:都柏林城市中心4个公园内共有树木24科43属65种(含种下等级),以蔷薇科、壳斗科、槭树科和桦木科占较大优势;圣斯蒂芬斯绿地、梅里恩广场、伊菲花园、菲茨威廉广场常绿树种与落叶树种比例分别为:1∶5、1∶5、1∶4和1∶5。各公园树木组成的相似性不高,但面积大的公园之间具有更接近的相似系数,面积小的公园之间亦是如此;公园内的树木种群分布结构宽泛,其中二球悬铃木、枸骨叶冬青、冬青栎、欧亚槭、椴树、欧洲七叶树等树木在各公园内具有较高数值;重要值同时也反映出各公园均以少数树种(2~3个)构成了公园的主体,其中二球悬铃木和欧洲七叶树是早期较为广泛选用的树种,目前已成为多数公园的乔木主体。结合多样性4个指数的分析结果,梅里恩广场物种多样性均优于其他3个公园。

In order to understand the structure of tree diversity in the city centre of Dublin, the tree diversity distributed in the St. Stephen′s Green, Merrion Square, Iveagh Gardens and Fitzwilliam Square were investigated, which were also analyzed by the parameters of relative importance, diversity indices and similarity coefficient. Results showed that there were 65 species （or variants）, belonging to 24 families 43 genera, which of them were in the main from Rosaceae, Fagaceae, Aceraceae and Betulaceae. Among these species, the proportion of deciduous and evergreen trees in the St. Stephen′s Green, Merrion Square, Iveagh Gardens and Fitzwilliam Square is about 1∶5, 1∶5, 1∶4 and 1∶5, respectively. From the viewpoint of similarity coefficient, there was a low similar on the species composition among the parks, but there was closer similarity coefficient between the larger parks, the same as the smaller ones. The integral population structures were widely distributed. The values of relative importance indicated that Platanus hispanica, Ilex aquifolium, Quercus ilex, Acer pseudoplatanus, Tilia sp. and Aesculus hippocastanum; meanwhile, number of 2 or 3 trees species constituted the main body in each parks. Based on the analysis of the dominant tree species, P.hispanica and A.pseudoplatanus were planted in the early stage, which of them were the most important species in the parks. According to the 4 indices of species diversity, the result of Merrion Square was better than the 3 others.