中文摘要：

以海南尖峰岭热带山地雨林3块1 hm～2样地为研究对象,利用11个林冠功能性状结合样地地形及林冠乔木树种样地清查数据,分别基于单维性状和多维性状比较物种多度加权对群落功能离散度指数——平均成对距离（MPD）和平均最近类群距离（MNTD）的影响;同时分析林冠层功能丰富度（FRic）与物种丰富度之间的关系,最后利用零模型探讨不同生境类型下标准化效应MPD和MNTD（经过物种多度加权且剔除群落物种丰富度差异影响）的变化,进而评价林冠层群落水平功能多样性格局及其对局域生境异质性的响应.结果表明：功能性状维度和物种多度对MPD的影响强烈,不同维度功能性状多度加权前后MPD相关性较弱（R=0.359～0.628）;但对MNTD的影响相对较弱,不同维度功能性状多度加权前后MNTD相关性较强（R=0.746～0.820）;未经物种多度加权的MPD和MNTD均普遍高估了林冠层的功能离散度.林冠层功能丰富度与物种丰富度基本呈指数相关关系（F=128.20;R^2=0.632;AIC=97.72;P〈0.001）,且功能丰富度很有可能存在一定的物种丰富度阈值.基于不同维度功能性状的林冠层功能多样性格局及其生境响应存在一定的差异性.在生物竞争激烈的低沟生境中,林冠层功能多样性倾向于比预期零模型随机产生的功能多样性高,林冠树种功能性状表现出离散分布;而在其他生境类型中,林冠层功能多样性倾向于接近或低于随机产生的功能多样性,林冠树种功能性状随机或聚集分布.

英文摘要：

Based on three 1-hm2 plots of Jianfengling tropical montane rainforest on Hainan Island, 11 commom used functional traits of canopy trees were measured. After combining with topographi- cal factors and trees census data of these three plots, we compared the impacts of weighted species abundance on two functional dispersion indices, mean pairwise distance （MPD） and mean nearest taxon distance （MNTD）, by using single- and multi-dimensional traits, respectively. The relation- ship between functional richness of the forest canopies and species abundance was analyzed. We used a null model approach to explore the variations in standardized size effects of MPD and MNTD, which were weighted by species abundance and eliminated the influences of species richness diffe- rences among communities, and assessed functional diversity patterns of the forest canopies and their responses to local habitat heterogeneity at community＇ s level. The results showed that variation in MPD was greatly dependent on the dimensionalities of functional traits as well as species abundance. The correlations between weighted and non-weighted MPD based on different dimensional traits were relatively weak （R=0.359-0.628）. On the contrary, functional traits and species abun- dance had relatively weak effects on MNTD, which brought stronger correlations between weighted and non-weighted MNTD based on different dimensional traits （R= 0.746-0.820）. Functional dis- persion of the forest canopies were generally overestimated when using non-weighted MPD and MNTD. Functional richness of the forest canopies showed an exponential relationship with species abundance （ F= 128.20 ; R2 = 0.632 ; AIC = 97.72 ; P〈0.001 ）, which might exist a species abun- dance threshold value. Patterns of functional diversity of the forest canopies based on different di- mensional functional traits and their habitat responses showed variations in some degree. Forest can- opies in the valley usually had relatively stronger biological competition, and functio