Hu Yuxin, Zhang Jing, Wang Yingcai, Hu Sheng
Yangtze River Basin Ecological Environment Monitoring and Scientific Research Center, Yangtze River Basin Ecological Environment Supervision and Administration Bureau, Ministry of Ecology and Environment, Wuhan 430010, Hubei, China.
Yangtze River Basin Ecological Environment Monitoring and Scientific Research Center, Yangtze River Basin Ecological Environment Supervision and Administration Bureau, Ministry of Ecology and Environment, Wuhan 430010, Hubei, China.
Water Res. 2023 Oct 15;245:120601. doi: 10.1016/j.watres.2023.120601. Epub 2023 Sep 9.
Changes in land-use intensity can have a far-reaching impact on river water quality and prokaryotic community composition. While research has been conducted to investigate the assembly mechanism of prokaryotic communities, the contributions of neutral theory and niche theory to prokaryotic community assembly under different land-use intensities remain unknown. In this study, a total of 251 sampling sites were set up in the Yangtze River basin to explore the assembly mechanism under different land-use intensities. Briefly, a "source" landscape can generate pollution, whereas a "sink" landscape can prevent pollution. Firstly, our result showed that higher land-use intensity might disturb the balance between the "source" and "sink" landscape patterns, resulting in water quality deterioration. Then the prokaryotic community assembly was classified into five ecological processes, namely homogeneous selection, homogenizing dispersal, undominated processes, dispersal limitation, and variable selection. The higher land-use intensity was found to strengthen the homogeneous selection, leading to the homogenization of the community at the whole basin scale. Finally, our findings demonstrated that the Yangtze River Basin's prokaryotic community displayed a distance-decay pattern when land-use intensity was low, with a greater contribution from neutral theory to its assembly. On the other hand, with a higher land-use intensity, the degradation of the aquatic environment increased the impacts of environmental filtering on the prokaryotic community, and niche theory played a stronger role in its assembly. Our findings show how land-use intensity influence the formation of prokaryotic communities, which will be an invaluable guide for managing land use and understanding the prokaryotic community assembly mechanisms in the Yangtze River Basin.
土地利用强度的变化会对河流水质和原核生物群落组成产生深远影响。虽然已有研究探讨原核生物群落的组装机制，但在不同土地利用强度下，中性理论和生态位理论对原核生物群落组装的贡献仍不清楚。在本研究中，长江流域共设置了251个采样点，以探究不同土地利用强度下的组装机制。简而言之，“源”景观会产生污染，而“汇”景观则可防止污染。首先，我们的结果表明，较高的土地利用强度可能会扰乱“源”与“汇”景观模式之间的平衡，导致水质恶化。然后，原核生物群落组装被分为五个生态过程，即同质选择、同质化扩散、非主导过程、扩散限制和可变选择。研究发现，较高的土地利用强度会加强同质选择，导致整个流域尺度上群落的同质化。最后，我们的研究结果表明，当土地利用强度较低时，长江流域的原核生物群落呈现出距离衰减模式，中性理论对其组装的贡献更大。另一方面，随着土地利用强度的提高，水生环境的退化增加了环境过滤对原核生物群落的影响，生态位理论在其组装中发挥了更强的作用。我们的研究结果表明了土地利用强度如何影响原核生物群落的形成，这将为长江流域的土地利用管理和理解原核生物群落组装机制提供宝贵的指导。
