She Yuanyang, Wang Peng, Wen Jiawei, Ding Mingjun, Zhang Hua, Nie Minghua, Huang Gaoxiang
School of Geography and Environment, Jiangxi Normal University, Nanchang, China.
Key Laboratory of Poyang Lake Wetland and Watershed Research, Ministry of Education, Jiangxi Normal University, Nanchang, China.
Front Microbiol. 2024 Nov 21;15:1463549. doi: 10.3389/fmicb.2024.1463549. eCollection 2024.
Bacterial communities play a crucial role in maintaining the stability of river ecosystems and driving biogeochemical cycling, exhibiting high sensitivity to environmental change. However, understanding the spatial scale effects and assembly mechanisms of riverine bacterial communities under distinct anthropogenic disturbances remains a challenge. Here, we investigated bacterial communities across three distinct watersheds [i.e., intensive urban (UW), intensive agricultural (AW), and natural (NW)] in both dry and wet seasons. We explored biogeographic patterns of bacterial communities and the influence of landscape patterns at multi-spatial scales and water chemistry on bacterial communities. Results showed that diversity was significantly lower in UW and AW compared to NW, particularly in the dry season. A gradient of diversity with NW > UW > AW was observed across both seasons ( < 0.05). Pseudomonadota, Bacteroidota, and Actinobacteriota were the most abundant phyla across all watersheds, with specific taxa enriched in each watershed (i.e., the class was significant enrichment in UW and AW, and in NW). The influence of landscape patterns on bacterial communities was significantly lower in human-disturbed watersheds, particularly in UW, where this influence also varied slightly from near riparian buffers to sub-watershed. Homogeneous selection and drift jointly dominated the bacterial community assembly across all watersheds, with homogeneous selection exhibiting a greater influence in UW and AW. Landscape patterns explained less variance in bacterial communities in UW and AW than in NW, and more variance was explained by water chemistry (particularly in UW). These suggest that the stronger influence of species sorting in UW and AW was driven by more allochthonous inputs of water chemistry (greater environmental stress). These findings provide a theoretical foundation for a deeper understanding of riverine bacterial community structure, spatial scale effects, and ecological management under different anthropogenic activities.
细菌群落对于维持河流生态系统的稳定性和推动生物地球化学循环起着至关重要的作用，对环境变化表现出高度敏感性。然而，了解不同人为干扰下河流细菌群落的空间尺度效应和组装机制仍然是一项挑战。在此，我们调查了三个不同流域（即城市集约化流域（UW）、农业集约化流域（AW）和自然流域（NW））在旱季和雨季的细菌群落。我们探索了细菌群落的生物地理模式以及多空间尺度下景观格局和水化学对细菌群落的影响。结果表明，与NW相比，UW和AW中的多样性显著较低，尤其是在旱季。在两个季节中均观察到多样性梯度为NW > UW > AW（< 0.05）。变形菌门、拟杆菌门和放线菌门是所有流域中最丰富的门类，每个流域都有特定的分类群富集（即 纲在UW和AW中显著富集，而在NW中富集）。在受人类干扰的流域中，景观格局对细菌群落的影响显著较低，尤其是在UW，这种影响从近河岸缓冲带到子流域也略有变化。同质选择和漂变共同主导了所有流域的细菌群落组装，同质选择在UW和AW中表现出更大的影响。景观格局对UW和AW中细菌群落的解释方差比NW中的少，而水化学解释的方差更多（尤其是在UW）。这些表明，UW和AW中物种分选的更强影响是由水化学的更多外源输入（更大的环境压力）驱动的。这些发现为更深入了解不同人为活动下河流细菌群落结构、空间尺度效应和生态管理提供了理论基础。
