Functional and phylogenetic diversity and assemblage structure of frugivorous birds along an elevational gradient in the tropical Andes
Functional and phylogenetic diversity and assemblage structure of frugivorous birds along an elevational gradient in the tropical Andes
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DOI：
10.1111/ecog.00623
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发表时间：
2014-11-01
期刊：
影响因子：
5.9
通讯作者：
Schleuning, Matthias
中科院分区：
文献类型：
--
作者：
Dehling, D. Matthias;Fritz, Susanne A.;Schleuning, Matthias
热带山区是生物多样性的热点，但对产生这种高度多样性的因素仍然知之甚少。为了确定可能的机制，影响鸟类物种组合在热带安第斯山脉，我们研究了功能和系统发育的多样性和结构的鸟类摄食公会的物种组合。我们分析了如何功能和系统发育的多样性，结构和组成的食果鸟类组合的变化沿着3300米的海拔样带从低地到树线的功能和系统发育的方法的新组合，并使用空模型来推断可能的驱动程序所观察到的模式。物种丰富度，功能丰富度和系统发育多样性几乎单调下降，随着海拔的增加，但组合结构和组成突然改变在安第斯山麓约1200米。在低地组合中，物种的功能和遗传相似性低于预期的空模型，而在高地组合中的物种的功能和遗传相似性高于预期的机会，这表明在从低地到高地的过渡功能和遗传不同的物种的数量突然减少。然而，功能和系统发育的均匀性的组合，即物种的间距在功能性状空间和系统发育的规律性，保持恒定的沿着梯度，这表明，在低地和高地的组合内的物种共存的影响机制是相似的。观察到的差异之间的低地和高地组合意味着急剧的分布限制食果鸟类物种在安第斯山麓，可能造成的环境因素，而不是气候，例如，在栖息地类型或地形的变化，或独立的物种在低地和高地的辐射。这些强大的分布限制可能会阻碍食果鸟类物种的上坡范围转移，以及它们在热带安第斯山脉传播的植物物种，作为对气候变化的反应。
Tropical mountains are hotspots of biodiversity, but the factors that generate this high diversity remain poorly understood. To identify possible mechanisms that influence avian species assemblages in the tropical Andes, we studied the functional and phylogenetic diversity and the structure of species assemblages of an avian feeding guild. We analysed how functional and phylogenetic diversity, structure and composition of frugivorous bird assemblages changed along a 3300 m elevational transect from the lowlands to the tree line with a novel combination of functional and phylogenetic approaches, and used null models to infer possible drivers of the observed patterns. Species richness, functional richness and phylogenetic diversity decreased almost monotonically with increasing elevation, but assemblage structure and composition changed abruptly in the Andean foothills at around 1200 m. In the lowland assemblages, species were functionally and phylogenetically less similar than expected from null models, whereas species in the highland assemblages were functionally and phylogenetically more similar than expected by chance, suggesting an abrupt reduction in the number of functionally and phylogenetically distinct species in the transition from lowlands to the highlands. Nevertheless, the functional and phylogenetic evenness of the assemblages, i.e. the regularity of the spacing of species in functional trait space and phylogeny, remained constant along the gradient, which suggests that the mechanisms that influence the co-occurrence of species within the assemblages are similar in lowlands and highlands. The observed differences between lowland and highland assemblages imply sharp distributional limits for frugivorous bird species in the Andean foothills, probably caused by environmental factors other than climate, e.g. changes in habitat types or topography, or independent species radiations in lowlands and highlands. These strong distributional limits may hinder uphill range shifts of frugivorous bird species, and the plant species they disperse, in the tropical Andes as a response to climate change.