生态位分化和谱系进化对南岭森林鸟类混合群构建的比较研究

As a characteristic feature of social organization of forest avifauna, mixed-species bird flocks represent an adaptive advantage of community assembly process, which result from an interaction between ecological and evolutionary effects. We previously found that both foraging niche overlap and expansion among flocking members could facilitate the formation and maintenance of flocks, yet our understanding of the mechanisms of assembly patterns have remained elusive. Based on the observed non-random distributional patterns and foraging niche structure of mixed-species bird flocks in Nanling mountain region, Guangdong, this program will testify the hypothesis that local and regional processes structure species assemblages in flocks. To compare the relative importance of interspecific competition, inter-guild competition, and morphological segregation in structuring selection process at local scale, several co-occurrence patterns and assembly rules (i.e. Diamond's co-occurrence pattern, guild proportionality, and constant body-size ratios) are tested. Furthermore, the study of community phylogenetic structure provide an effective way to reveal the ecological processes that driving assembly pattern of mixed-species bird flocks at multiple scales. By statistically comparing the phylogenetic structure distance of flocking species with random null model, an inference of phylogenetic trait distribution (e.g. clustering, over-dispersed) will be obtained, hence revealing key ecological processes involved in assembly pattern of mixed flocks (e.g. habitat filtering, competition exclusion), and finally clarifying underling regional processes (e.g. speciation, dispersal, geological history). The study will enhance local understanding of social aggregation pattern and community assembly rules of mixed-species bird flocks, and benefit in local forest bird conservation of southern China.

鸟类混合群作为局域鸟类群落的典型社会组织形式，是群落构建中生态过程与进化过程相互动态作用而产生的适应进化结果。前期研究中，我们发现集群鸟种在觅食过程中存在生态位重叠及扩展的现象，但其构建机制尚不明确。为证明生态选择过程和谱系进化过程在不同尺度对混合群构建成因的作用机理，本课题以广东南岭山地鸟类混合群的空间分布格局和觅食生态位结构为前提，检验基于生态位理论的群落构建规则假说(Diamond共存格局，集团比例和恒定身体比率)，从局域生态选择角度揭示种间竞争、集团间竞争和形态差异在混合群构建中的作用机理；同时通过群落水平的系统发育研究，分析集群鸟种的谱系结构特征(如谱系聚集、谱系发散)，从区域谱系进化角度阐明混合群构建中的关键生态过程(如生境过滤、竞争作用)，探讨物种形成、地史过程等历史因素对混合群构建的影响。研究成果可丰富群落社会组织的构建理论，对我国华南地区森林鸟类多样性的保护起指导作用。

森林鸟类多物种集群共存作为局域鸟类群落的典型社会组织形式，是群落构建中生态过程与进化过程相互动态作用而产生的适应进化结果，并形成增加觅食效率和降低被捕食风险两种优势假说。本研究发现：（1）集群鸟种在觅食过程中通过生态位重叠及扩展促进混合群的稳定共存，灰眶雀鹛是南岭山地的核心种；（2）功能特征的分化对鸟类多物种集群共存起到关键作用，如栖息地选择、食性分化以及形体度量特征，从而揭示了竞争排斥在局域生态选择过程的构建作用；（3）群落水平的系统发育研究表明，南岭山地集群鸟种的谱系结构特征较为发散，因此物种形成、地史过程等历史因素对混合群构建的影响较小；（4）干扰作用下集群鸟种表现出显著的行为可塑性，如增加种间集群频率，降低觅食高度。上述研究成果丰富了群落社会组织的构建理论，对我国华南地区森林鸟类多样性的保护起到指导作用。