Bacterial dispersal and drift drive microbiome diversity patterns within a population of feral hindgut fermenters

Studies of microbiome variation in wildlife often emphasize host physiology and diet as proximate selective pressures acting on host-associated microbiota. In contrast, microbial dispersal and ecological drift are more rarely considered. Using amplicon sequencing, we characterized the bacterial microbiome of adult female (n = 86) Sable Island horses (Nova Scotia, Canada) as part of a detailed individual-based study of this feral population. Using data on sampling date, horse location, age, parental status, and local habitat variables, we contrasted the ability of spatiotemporal, life history, and environmental factors to explain microbiome diversity among Sable Island horses. We extended inferences made from these analyses with both phylogeny-informed and phylogeny-independent null modeling approaches to identify deviations from stochastic expectations. Phylogeny-informed diversity measures were correlated with spatial and local habitat variables, but null modelling results suggested th...针对野生动物微生物组（microbiome）变异的相关研究，通常将宿主生理与饮食视为作用于宿主关联微生物群的直接选择压力。与之相对，微生物扩散与生态漂变（ecological drift）的相关影响则较少被纳入考量范畴。本研究作为针对该野生种群的精细化个体水平研究的一部分，采用扩增子测序（amplicon sequencing）技术，对加拿大新斯科舍省塞布尔岛的86头成年雌性马的细菌微生物组进行了表征。本研究基于采样日期、马匹位置、年龄、亲本状态以及局域生境变量等数据，对比了时空因素、生活史因素与环境因素对塞布尔岛马微生物组多样性的解释能力。本研究同时采用系统发育信息驱动与无系统发育的零模型（null modeling）方法，对上述分析得到的推论进行了拓展，以识别偏离随机预期的模式。系统发育信息驱动的多样性指标与空间及局域生境变量存在相关性，但零模型分析结果显示……