Community structure and assembly of myxomycetes in northern Chinese forests under geographic barriers

The study of myxomycete biogeography has a long-standing history and has consistently drawn scholarly interest. Nevertheless, studies focusing specifically on the spatial and temporal distribution patterns of myxomycete diversity are relatively limited, with even fewer investigating the mechanisms driving the generation and maintenance of myxomycete diversity. Therefore, this study selected two geographically distant sampling sites within northern Chinese forests to investigate myxomycete species composition, community structure, environmental drivers, and assembly patterns under geographic barriers. We established plots in the Altai Mountains (ALE) and the Greater Khingan Mountains (GKM), gathered bark and litter, and conducted 80-day moist chamber cultures of myxomycetes. Additionally, myxomycete specimens were collected in the field simultaneously to supplement the data set. This study collected 541 myxomycete specimens belonging to 73 species from 28 genera, spanning 12 families and eight orders. The ALE and the GKM had 20 identical species, accounting for 27% of the total species. Myxomycetes from both regions exhibited abundant occurrence 18 days after cultivation, with the quantity on bark substrates notably higher than on litter. <i>Arcyria pomiformis</i> and <i>Comatricha elegans</i> were the most common species in moist chamber cultures. Mantel test outcomes revealed that environmental factors had no significant impact on myxomycete community similarity between the two areas, aligning with findings from the neutral community model analysis, indicating a predominant influence of stochastic processes on myxomycete community structure in moist chamber cultures. This study represents the first application of a quantitative framework to analyze myxomycete community assembly cultivated in moist chambers.

黏菌（myxomycete）生物地理学研究历史悠久，长期以来广受学术关注。然而，专门针对黏菌多样性时空分布格局的研究仍相对匮乏，针对黏菌多样性产生与维持机制的探究更是寥寥无几。鉴于此，本研究选取中国北方森林中两个地理距离相隔较远的采样点，以探究地理屏障下黏菌的物种组成、群落结构、环境驱动因子及群落组装模式。我们在阿尔泰山脉（ALE）与大兴安岭（GKM）设立样地，收集树皮与枯落物样本，并开展为期80天的黏菌湿室培养。此外，本研究同步开展野外黏菌标本采集工作，以补充数据集。本研究共收集黏菌标本541份，涵盖8目、12科、28属，共计73种。阿尔泰山脉（ALE）与大兴安岭（GKM）共拥有20个共有物种，占总物种数的27%。两个区域的黏菌均在培养18天后大量出现，树皮基质上的黏菌数量显著高于枯落物基质。湿室培养中最常见的物种为梨形团网菌（*Arcyria pomiformis*）与雅致发网菌（*Comatricha elegans*）。曼特尔检验（Mantel test）结果显示，环境因子对两个区域间黏菌群落相似性无显著影响，这与中性群落模型分析结果一致，表明湿室培养下的黏菌群落结构主要受随机过程驱动。本研究首次采用定量框架分析湿室培养黏菌的群落组装模式。