Data from: A taxonomic, functional and phylogenetic perspective on the community assembly of passerine birds along an elevational gradient in southwest China

Integrating multiple-facets of biodiversity to describe spatial and temporal distribution patterns is one way of revealing the mechanisms driving community assembly. We assessed the species, functional and phylogenetic composition and structure of passerine bird communities along an elevational gradient both in wintering and breeding seasons in the Ailao Mountains, southwest China, in order to identify the dominant ecological processes structuring the communities and how these processes change with elevation and season. Our research confirms that the highest taxonomic diversity, and distinct community composition, was found in the moist evergreen broadleaf forest at high elevation in both seasons. Environmental filtering was the dominant force at high elevations with relatively cold and wet climatic conditions, while the observed value of mean pairwise functional and phylogenetic distances of low elevation were constantly higher than expectation in two seasons, suggested interspecific competition could played the key role at low elevations, perhaps because of relative rich resource result from complex vegetation structure and human-induced disturbance. Across all elevations, there was a trend of decreasing intensity of environmental filtering whereas increasing interspecific competition from wintering season to breeding season. This was likely due to the increased resource availability but reproduction-associated competition in the summer months. In general, there is a clear justification for conservation efforts to protect entire elevational gradients in the Ailao Mountains, given the distinct taxonomic, functional and phylogenetic compositions and also elevational migration pattern in passerine bird communities.整合生物多样性（biodiversity）的多个维度以描述时空分布格局，是揭示群落构建（community assembly）机制的重要途径之一。本研究于中国西南哀牢山，沿海拔梯度（elevational gradient）在越冬期（wintering season）与繁殖期（breeding season）对雀形目鸟类（passerine bird）群落开展调查，评估其物种、功能与系统发育的组成与结构，旨在明确调控群落构建的主导生态过程，以及这些过程随海拔与季节的变化规律。研究证实，两个季节中高海拔的湿润常绿阔叶林（moist evergreen broadleaf forest）均呈现出最高的分类多样性（taxonomic diversity），且群落组成独具特色。在寒冷湿润的高海拔生境中，环境过滤（environmental filtering）是主导群落构建的核心过程；而低海拔区域的平均成对功能距离（mean pairwise functional distance）与平均成对系统发育距离（mean pairwise phylogenetic distance）的观测值在两个季节均持续高于预期值，表明种间竞争（interspecific competition）可能在低海拔区域发挥关键作用，这或许源于复杂植被结构与人类活动干扰（human-induced disturbance）所造就的相对丰富的资源。在所有海拔梯度上，从越冬期到繁殖期，环境过滤的作用强度呈下降趋势，而种间竞争的强度则逐渐增强，这可能与夏季资源可获得性（resource availability）提升以及繁殖相关的竞争压力增加有关。综上，鉴于哀牢山雀形目鸟类群落在分类、功能与系统发育组成上的独特性，以及其沿海拔的迁移模式，保护该区域完整海拔梯度的生态系统具有充分的科学依据。