中国东部海岛黑松群落功能多样性的纬度变异及其影响因素

黑松(Pinus thunbergii)群落在中国东海和黄海海域的海岛广泛分布, 研究其功能多样性的纬度变化特征及其影响因素, 有助于揭示是否在高度隔离的片断化景观中, 同一植物群落类型的生物多样性也具有显著的纬度地带性特征。该研究调查和测定了中国东部海域跨越13个纬度的27个海岛60个黑松群落的物种组成和植物功能性状, 分析了生物因素(黑松优势度和物种多样性)与非生物因素(年平均气温、总太阳辐射和干旱指数)与黑松群落功能多样性的关系, 并利用广义线性回归和方差分解揭示了各影响因素对黑松群落功能多样性的相对影响。主要结果: 随纬度升高, 群落的黑松优势度和物种丰富度, 以及枝干性状和枝叶性状总体的功能丰富度、功能分散度、Rao二次熵均显著降低, 但叶片功能多样性无显著变化趋势。黑松优势度、物种多样性和气候综合解释了枝叶性状总体功能丰富度、分散度和Rao二次熵变异的63%、47%和39%, 枝干性状功能丰富度、分散度和Rao二次熵变异的56%、67%和53%, 对叶片性状功能多样性的综合解释度较低(21%-30%)。物种丰富度和辛普森多样性显著增加叶功能多样性, 香农-维纳多样性显著降低叶功能丰富度。干旱度显著增加枝叶性状总体和枝干功能多样性, 年平均气温显著降低枝干功能分散度和Rao二次熵。该结果表明, 中国东部海岛黑松群落的功能多样性具有明显的纬度格局, 气候因素和物种丰富度是决定黑松群落功能多样性纬度变异的重要因素。

Latitudinal variability and driving factors of functional diversity in Pinus thunbergiicommunities across sea-islands in Eastern China

Aims The Pinus thunbergii communities is widespread across islands in both Yellow Sea and East China Sea. The objective of this study is to examine the latitudinal pattern of functional diversity and abiotic and biotic drivers of P. thunbergii communities. Our aims are to advance understanding of whether the zonal character of latitude oriented pattern of biodiversity still holds in the same community type across the highly isolated and fragmented landscape.Methods We investigated community structure and measured plant functional traits across 60 P. thunbergii communities in 27 islands, spanning 13 degree in latitudes of Eastern China. Linear regression was used to analyze the relationships between functional diversity of the P. thunbergii community and each of the biotic factors (the dominance of P. thunbergii and species diversity) and abiotic factors (annual mean temperature, total solar radiation and aridity index). The relative importance of abiotic and biotic factors on the functional diversity of P. thunbergii communities was determined by using the generalized linear model and variance decomposition.Important findings With the increasing latitude, the dominance of P. thunbergii,species richness, and functional richness, functional dispersion and Rao's quadratic entropy (RaoQ) of stem traits alone and stem and leaf traits in combination decreased significantly but those of leaf traits did not show clear trend, across P. thunbergii communities. The dominance of P. thunbergii, species richness and climatic factors jointly explained 63%, 47% and 39% of variation in each of functional richness, functional dispersion and RaoQ of the combination of leaf and stem traits, and 56%, 67% and 53% of variation in each of functional richness, functional dispersion and RaoQ of stem traits, but small variations in leaf traits (21%-30%). Species richness and Simpson diversity significantly increased but Shannon-Wiener diversity significantly decreased leaf functional richness. Aridity significantly increased functional diversity of stem traits and the combination of leaf and stem traits. Annual mean temperature significantly decreased functional dispersion and RaoQ of wood traits. These results indicate that there is a clear latitudinal pattern of functional diversity in P. thunbergii communities across islands. Climate and species richness play the key roles for shaping the latitudinal variations in functional diversity of P. thunbergii communities across islands in Eastern China.