Cisneros Laura M, Burgio Kevin R, Dreiss Lindsay M, Klingbeil Brian T, Patterson Bruce D, Presley Steven J, Willig Michael R
Department of Ecology and Evolutionary Biology, University of Connecticut, 75 North Eagleville Road, Storrs, CT, 06269-3043, USA.
Center for Environmental Sciences and Engineering, University of Connecticut, 3107 Horsebarn Hill Road, Storrs, CT, 06269-4210, USA.
J Anim Ecol. 2014 Sep;83(5):1124-36. doi: 10.1111/1365-2656.12201. Epub 2014 Feb 12.
Research concerning spatial dynamics of biodiversity generally has been limited to considerations of the taxonomic dimension, which is insensitive to interspecific variation in ecological or evolutionary characteristics that play important roles in species assembly and provide linkages to ecosystem services. Consequently, the assumption that the taxonomic dimension is a good surrogate for other dimensions remains unconfirmed. We assessed variation in taxonomic (species richness) as well as phylogenetic and functional (Rao's quadratic entropy, a measurement of dispersion) dimensions of bat biodiversity along an elevational gradient in the Manu Biosphere Reserve of Peru. Phylogenetic dispersion was based on relatedness of species derived from a mammalian supertree. Functional dispersion was estimated separately for each of six functional components that reflect particular niche axes (e.g. diet, foraging strategy, body size) and for all functional components combined. Species richness declined nonlinearly with elevation, whereas phylogenetic dispersion and functional dispersion based on all functional components were not significantly associated with elevation (orthogonal polynomial regression). Moreover, considerable heterogeneity in the form of elevational relationships existed among functional components. After accounting for variation in species richness, dispersion of phylogenetic, diet and foraging strategy attributes were significantly greater than expected at high elevations, whereas dispersion of body size was significantly less than expected at high elevations. Species richness was a poor surrogate for phylogenetic or functional dispersion. Functional dispersion based on multiple components obscured patterns detected by particular components and hindered identification of mechanistic explanations for elevational variation in biodiversity. Variation in phylogenetic dispersion effectively captured the composite variation represented by all functional components, suggesting a phylogenetic signal in functional attributes. Mechanisms that give rise to variation in richness do not fully account for variation in phylogenetic or functional characteristics of assemblages. Greater than expected phylogenetic, diet and foraging strategy dispersion at high elevations were associated with the loss of phylogenetically or functionally redundant species, suggesting that increasing interspecific competition with decreasing productivity resulted in competitive exclusion. In contrast, low dispersion of size attributes at high elevations suggests the importance of abiotic filtering that favours small-sized species that can more easily enter torpor.
关于生物多样性空间动态的研究通常仅限于分类学维度的考量，而分类学维度对生态或进化特征的种间变异不敏感，这些特征在物种组装中发挥重要作用并与生态系统服务相联系。因此，分类学维度是其他维度良好替代指标的假设仍未得到证实。我们评估了秘鲁马努生物圈保护区沿海拔梯度的蝙蝠生物多样性在分类学（物种丰富度）以及系统发育和功能（Rao二次熵，一种离散度测量指标）维度上的变化。系统发育离散度基于从哺乳动物超级树得出的物种亲缘关系。针对反映特定生态位轴（如饮食、觅食策略、体型）的六个功能组分中的每一个以及所有功能组分的组合分别估算功能离散度。物种丰富度随海拔呈非线性下降，而基于所有功能组分的系统发育离散度和功能离散度与海拔无显著关联（正交多项式回归）。此外，各功能组分之间存在以海拔关系形式表现的相当大的异质性。在考虑物种丰富度的变化后，系统发育、饮食和觅食策略属性的离散度在高海拔地区显著大于预期，而体型的离散度在高海拔地区显著小于预期。物种丰富度并非系统发育或功能离散度的良好替代指标。基于多个组分的功能离散度掩盖了特定组分检测到的模式，并阻碍了对生物多样性海拔变化的机理解释的识别。系统发育离散度的变化有效地捕捉了所有功能组分所代表的综合变化，表明功能属性中存在系统发育信号。导致丰富度变化的机制并不能完全解释群落系统发育或功能特征的变化。高海拔地区系统发育、饮食和觅食策略离散度大于预期与系统发育或功能冗余物种的丧失有关，这表明随着生产力下降种间竞争加剧导致了竞争排斥。相反，高海拔地区体型属性的低离散度表明非生物过滤的重要性，这种过滤有利于能够更轻松进入蛰伏状态的小型物种。
