福建平潭岛滨海砂生种子植物植被资源及其区系特征分析

平潭岛位于中国东南沿海,是福建省第一大岛,通过样线法和样方法对平潭岛的滨海砂生种子植物进行调查,发现平潭岛共有滨海砂生种子植物71种,隶属64属31科。种数最多的6个科依次为禾本科、菊科、苋科、豆科、莎草科和旋花科。平潭岛砂生种子植物区系以世界分布为主,共有16科13属,分别占总科数和总属数的51.61%和20.31%。热带性质明显,与各大洲热带地区植物联系广泛,热带成分有11科（占除世界分布科的73.33%）38属（占除世界分布属的74.51%）,科和属均以泛热带成分为主;温带成分仅有4科（占除世界分布科的26.67%）13属（占除世界分布属的25.49%）;在种级水平上,热带性质成分依旧占绝大部分,多达36种,占除世界分布种的56.25%,温带性质则有27种,占除世界分布种的42.19%,世界分布型有7种,占总种数的9.86%。比较平潭岛与中国由北到南5个区域滨海砂地种子植物区系地理成分,发现平潭岛的滨海砂生种子植物区系与厦门岛的联系紧密,其次是浙江海岛的和山东海岸,而与海南岛的较为疏远。其中平潭岛与厦门岛种间的相似性系数达到55.34,而与海南岛的种间相似性系数仅有13.68。因纬度因素影响,平潭岛砂生植物属的R/T值（2.92）明显高于浙江海岛（1.18）和山东海岸（0.43）,而与海南岛属的R/T值（13.75）相差最大,这与可能与岛屿面积存在一定关系。平潭岛滨海砂地种子植物具有一定的纬向性分布规律,随着纬度的递增,属级别中温带成分所占的比重也逐渐增加;而热带成分则相反,与岛屿所处纬度的水分和热量分布特点有相似性。滨海砂生种子植物作为隐域植被,也受非气候因子的影响,非地带因素对海岸砂生植被中的植物分布具支配作用,在沙滩前缘的植物群落中表现尤为明显。这些滨海砂生植物大多是耐盐、耐旱、抗风的物种,距离海越近,非气候因子的作用越显著。

Vegetation Resources and Floristic Characteristics of Sand Seed Plants in Pingtan Island,Fujian Province

Pingtan Island is located in the southeast coast of China,and it is the largest island in Fujian Province.Through the line transect and sample method,71 species of coastal psammophyte seed plants,belonging to 64 genera and 31 families,were investigated on Pingtan Island.The six families with the largest number of species were gramineae,compositae,amaranthaceae,leguminosae,Sedge and convolvulaceae.The floras of psammophytes in Pingtan Island are mainly distributed worldwide,consisting of 16 families and 13 genera,accounting for 51.61% and 20.31%of the total families and genera,respectively.There were 11 families(73.33%) and 38 genera(74.51%) of the plants in the tropical regions of the world,and most of the families and genera were pan-tropical.There were only 4 families(26.67%) and 13 genera(25.49%) of temperate components.At the species level,36 tropical species accounted for 56.25% of the total species,27 temperate species accounted for 42.19% of the total species,and 7 global species accounted for 9.86%.The floristic composition of coastal sand seed plants in Pingtan Island was compared with that in five regions from north to south of China.It was found that the floristic composition of coastal sand seed plants in Pingtan Island was closely related to Xiamen Island,followed by Zhejiang island and Shandong coast,but was relatively distant from Hainan Island.The coefficient of interspecific similarity between Pingtan Island and Xiamen Island was 55.34,while that between Pingtan Island and Hainan Island was only 13.68.Due to the influence of latitude,the R/T value(2.92) of psam in Pingtan Island was significantly higher than that of Zhejiang Sea island(1.18) and Shandong coast(0.43),but the R/T value was the biggest difference with that of Hainan Island(13.75),which may be related to the island area.The seed plants in the coastal sandy land of Pingtan Island had a certain zonal distribution.With the increase of latitude,the proportion of temperate components in genus level increased gradually.The tropical component,on the other hand,was similar to the characteristics of water and heat distribution at the latitude of the island.Coastal sand seed plants,as hidden vegetation,were also affected by non-climatic factors,which dominated the distribution of plants in coastal sand vegetation,especially in the plant community of beach front.Most of the coastal sand plants are salt-tolerant,drought-tolerant and wind-resistant species.More significant effect of non-climatic factors would be found closer to the sea.