Institute of Environmental Research at Greater Bay, Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Ministry of Education, Guangzhou University, Guangzhou, 510006, China.
Department of Agronomy, Food, Natural Resources, Animals and Environment (DAFNAE), University of Padova, Padua, Italy.
Microb Ecol. 2023 Aug;86(2):1164-1175. doi: 10.1007/s00248-022-02152-z. Epub 2022 Dec 11.
Numerous rare species coexist with a few abundant species in microbial communities and together play an essential role in riparian ecosystems. Relatively little is understood, however, about the nature of assembly processes of these communities and how they respond to a fluctuating environment. In this study, drivers controlling the assembly of abundant and rare subcommunities for bacteria and archaea in a riparian zone were determined, and their resulting patterns on these processes were analyzed. Abundant and rare bacteria and archaea showed a consistent variation in the community structure along the riparian elevation gradient, which was closely associated with flooding frequency. The community assembly of abundant bacteria was not affected by any measured environmental variables, while soil moisture and ratio of submerged time to exposed time were the two most decisive factors determining rare bacterial community. Assembly of abundant archaeal community was also determined by these two factors, whereas rare archaea was significantly associated with soil carbon-nitrogen ratio and total carbon content. The assembly process of abundant and rare bacterial subcommunities was driven respectively by dispersal limitation and variable selection. Undominated processes and dispersal limitation dominated the assembly of abundant archaea, whereas homogeneous selection primarily driven rare archaea. Flooding may therefore play a crucial role in determining the community assembly processes by imposing disturbances and shaping soil niches. Overall, this study reveals the assembly patterns of abundant and rare communities in the riparian zone and provides further insight into the importance of their respective roles in maintaining a stable ecosystem during times of environmental perturbations.
微生物群落中存在大量的丰富物种和少数稀有物种，它们共同发挥着重要的作用。然而，人们对这些群落的组装过程的本质以及它们如何对波动的环境做出反应还了解甚少。在这项研究中，确定了控制河岸带丰富和稀有亚群落组装的驱动因素，并分析了它们对这些过程的影响。丰富和稀有种的细菌和古菌在河岸带的海拔梯度上表现出一致的群落结构变化，这与洪水频率密切相关。丰富细菌的群落组装不受任何测量的环境变量的影响，而土壤湿度和淹没时间与暴露时间的比例是决定稀有细菌群落的两个最关键因素。丰富古菌的群落组装也由这两个因素决定，而稀有古菌则与土壤碳氮比和总碳含量显著相关。丰富和稀有细菌亚群落的组装过程分别由扩散限制和可变选择驱动。非主导过程和扩散限制主导了丰富古菌的组装，而同质选择主要驱动了稀有古菌的组装。洪水可能通过施加干扰和塑造土壤小生境来决定群落的组装过程，因此在维持稳定的生态系统方面发挥着至关重要的作用。
