平潭光幼屿典型植物群落优势种生态位特征

为了解光幼屿典型植物群落中各物种在群落中的功能地位,为海岛植被保护与恢复提供借鉴,2018年9月对光幼屿上典型植物群落进行样方调查,通过生态位原理对岛上优势种的环境适应性以及不同物种间对资源的竞争关系进行分析。结果表明:(1)样方中共调查到种子植物38种,隶属于22科38属,其中菊科(Asteraceae)物种数最多,占全部物种数的23.7%;(2)物种重要值与生态位宽度没有明显的正相关关系(P>0.05),乔木层中的黑松与灌木层中的木麻黄在所属层次中重要值最大,但生态位宽度比部分重要值小的物种小;(3)海岛生存环境恶劣,植物为了获得更多的资源,多数物种的生态位宽度较大,乔灌草三层次中优势物种生态位宽度大于0.600的物种占总物种数的82.6%;(4)物种较大的生态位宽度导致不同物种间生态位重叠普遍较大,生态位重叠值大于0.500的对数占总对数的46.5%,种间竞争激烈。

Niche characteristics of dominant species in typical plant communities in Guangyou Island,Pingtan

Quadrat method was applied to the typical plant community of Guangyou Island in September 2018,and plant compositions,importance values of dominant species,niche breadth,and niche overlap were calculated and analyzed to elucidate the functional status of species in the surveyed plant community and provide references for the protection and restoration of island vegetation.The results showed:(1)38 species of seed plants in 6 quadrats,falling in 38 genera in 22 families;of these,the family Asteraceae,with9 species,showed the highest number of species,accounting for 23.7%of the total species.(2)There was no significant positive correlation between species importance value and niche breadth(P>0.05).Pinus thunbergii and Casuarina equisetifolia had the highest importance value in the arbor and shrub layer,respectively;however,the corresponding niche breadth values were smaller than those of other species in the respective layers,with smaller importance values.(3)The dominant species in three layers whose niche width values were more than 0.600 accounted for 82.6%of the total species number,which suggested that the dominant species obtain more resources to adapt to the harsh growing conditions on the island.(4)The larger niche width values of species casually results in larger niche overlap values of the corresponding species.The calculation results showed that the unique pairs with a niche overlap value of more than 0.500 accounted for 46.5%of the total pairs,which suggested fierce competition between species.