东山岛植被资源和物种多样性特征

Feature of species diversity and vegetational resources in Dongshan lsland

调查100块样地共1hm2并野外植被填图，岛上含维管植物84科160属184种，植物区系为热带、亚热带分布成分占总属数85．7％。对岛上16个群落中的植物种数和个体数作了物种丰富度指数D1、多样性指数D2、优势度指数D3、均匀度J等统计，其中相思树群落上述指数依次为8．124、12．502、2．878和71．93％；马尾松群落为8．676、18．468、3．354、83．13％，黑松群落为8．464、11．290、2．732、67．61％。说明该3个群落为相对稳定性较大的群落。各群落乔木种类4种指数变化幅度依次为0．185～2．012、1．017～2．628、0．078～1．006、11．25％～96．39％。灌木层上述指数变化幅度依次为1．083～4．468、2．014～16．028、1．006～2．687、57．49％～96．01％。显示了灌木层种类较为丰富，多样性较高，岛上植物属于闽粤沿海丘陵平原亚热带雨林区。

Based on field survey of 100 plots totalling l hm2 and the abundent data materials ac-quired, 184 species of vascular plants belonging to 16o genera and 84 families are idenfied inthe Dongshan Island. Analysis of floristic geographical elements indicates that the percent-age of tropical and pan-tropical elements makes up 85. 7% of the total number of genera. Itshows that the flora in the island is in consistant with the south-subtropical oceanic climate.Based on the indexes of species richness (D1 ),diversity index (D2),dominance (D3) and even-ness index (J ) in the 16 communities, the indexes are 8. 124, 12. 502, 2. 878 and 71. 93 % forAcaia cofusa, 8. 464, 11. 290, 2. 732 and 67- 61 % for Pinus thunbergii, and 8. 676, 18. 468,3. 354, 83. 13% for P. massoniana. It indlcates that these three group are most stable in theisland. The 4 indexes of arbor fluctuatc between 0.185~ 2.012 (D1); 1. 017~ 2. 628 (D2) ;0.078 ~ 1.006(D3); 11. 25% ~96. 39% (J) and of shrub between 1.083~4.468 (D1); 2.014~ 16.28 (D2); 1. 006~ 2. 687 (D3); 57. 49 % ~96. 01 %. It shows that the shrub possess moreabundant species and higher diversity and the flora in the island belongs to Fujian-Guangdong coastal mound-plain subtropical rain forest.