厦门市大屿岛主要乔木种生态位特征分析

Niche characteristics of important arbor species in Dayu Island,Xiamen

通过样方法对福建省厦门市大屿岛主要乔木种生态位特征进行分析。结果表明:整个岛屿乔木树种物种多样性较低,其中Shannon-Wiener物种多样性指数为1. 26,Margalef丰富度指数为1. 44,Simpson生态优势度指数为0. 54,Pielou均匀度指数为0. 57。乔木层优势物种是台湾相思(Acacia confusa),其重要值达53. 84%。其次是马尾松(Pinus massoniana)、柠檬桉(Eucalyptus citriodora)和潺槁木姜子(Litsea glutinosa)。生态位特征分析表明台湾相思生态位宽度最大,其Levins和Shannon生态位宽度值分别为19. 00和2. 84。生态位宽度较大的还有马尾松,潺槁木姜子和柠檬桉。台湾相思和马尾松的生态位重叠值最高,为0. 673,其次为台湾相思和潺槁木姜子,其生态位重叠值为0. 633。台湾相思、马尾松、柠檬桉和潺槁木姜子的胸径和冠幅在空间分布中变化趋势相似。综上可知厦门大屿岛乔木树种多样性较低,植物种类简单,优势种相对明显,生态位特征值较小的植物对生境要求较高,整个生态系统较为脆弱。

In this study the niche characteristics of important arbor species in Dayu Island, southeast China are analyzed with quadrate methods. The results showed that the diversity indexs of arbor species low, such as their Shannon-Wiener index 1.26, Margalef index 1.44, Simpson index 0.54 and Pielou index 0.57. The dominant species in the arbor layer was Acacia confusa , with important value of 53.84%. This was followed by Pinus massoniana , Eucalyptus citriodora and Litsea glutinosa . The analysis of niche characteristics indicated that the niche breadth of the Acacia confusa was the highest. The Levins niche breadth value was 19.00 and the Shannon niche breadth value was 2.84. Pinus massoniana , Litsea glutinosa and Eucalyptus citriodora also had larger niche breadth values. The highest niche overlap value of 0.673 was found between Acacia confusa and Pinus massoniana , followed by 0.633 between Acacia confusa and Litsea glutinosa . The DBH and crown diameter of Acacia confusa , Pinus massoniana , Eucalyptus citriodora and Litsea glutinosa were similar in their spatial distribution. In summary, the diversity index of arbor species in Dayu Island was low, the plant species were simple and the dominant species were relatively obvious. The plants with smaller niche characteristics had higher habitat requirements and the whole ecosystem was fragile.