Data from: Parasite metacommunities: evaluating the roles of host community composition and environmental gradients in structuring symbiont communities within amphibians

1. Ecologists increasingly report the structures of metacommunities for free-living species, yet far less is known about the composition of symbiont communities through space and time. Understanding the drivers of symbiont community patterns has implications ranging from emerging infectious disease to managing host microbiomes. 2. Using symbiont communities from amphibian hosts sampled from wetlands of California, USA, we quantified the effects of spatial, habitat filtering, and host community components on symbiont occupancy and overall metacommunity structure. 3. We built upon a statistical method to describe metacommunity structure that accounts for imperfect detection in survey data – detection error-corrected elements of metacommunity structure (DECEMS) – by adding an analysis to identify covariates of community turnover. We applied our model to a metacommunity of 8 parasite taxa observed in 3571 Pacific chorus frogs (Pseudacris regilla) surveyed from 174 wetlands over 5 years. 4. Symbiont metacommunity structure varied across years, showing nested structure in three years and random structure in two years. Species turnover was most consistently influenced by spatial and host community components. Occupancy generally increased in more southeastern wetlands, and snail (intermediate-host) community composition had strong effects on most symbiont taxa. 5. We have used sophisticated but accessible statistical methods to reveal that spatial components - which influence colonization - and host community composition - which mediates transmission - both drive symbiont community composition in this system. These methods allow us to associate broad patterns of community turnover to local, species-level effects, ultimately improving our understanding of spatial community dynamics.

1. 生态学家日益关注自由生活物种的集合群落（metacommunity）结构，但关于共生体（symbiont）群落在空间与时间维度上的组成，我们所知仍十分有限。阐明共生体群落格局的驱动机制，其研究意义涵盖新发传染病防控乃至宿主微生物组管理等诸多领域。
2. 本研究以美国加利福尼亚州湿地中采样的两栖动物宿主的共生体群落为研究对象，量化了空间因子、生境过滤作用以及宿主群落组分对共生体占据率与整体集合群落结构的影响。
3. 我们在一种用于描述集合群落结构的统计方法基础上进行拓展——该方法可校正调查数据中的检测偏差——即检测误差校正集合群落结构元素（detection error-corrected elements of metacommunity structure, DECEMS），新增了用于识别群落周转协变量的分析模块。我们将所提模型应用于一组集合群落数据：该数据涵盖5年间在174处湿地中采样的3571只太平洋树蛙（Pseudacris regilla）体内检出的8个寄生虫类群。
4. 共生体集合群落结构随年份存在显著变化：其中3年呈现嵌套结构，另外2年则呈随机结构。物种周转最常受空间因子与宿主群落组分的调控。共生体占据率在东南部湿地中普遍更高，而螺类（中间宿主）群落组成对多数共生体类群均具有显著影响。
5. 本研究采用了兼具严谨性与易用性的统计方法，结果揭示：影响定殖过程的空间因子，以及介导传播过程的宿主群落组成，共同驱动了本研究系统中共生体群落的组成格局。该方法可将群落周转的宏观格局与局域尺度的物种水平效应建立关联，最终增进我们对空间群落动态的理解。