Lin Yongxin, Hu Hang-Wei, Yang Ping, Ye Guiping
State Key Laboratory for Subtropical Mountain Ecology of the Ministry of Science and Technology and Fujian Province, School of Geographical Sciences, Fujian Normal University, Fuzhou 350007, China.
School of Agriculture and Food, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria 3010, Australia.
Sci Total Environ. 2022 May 20;822:153517. doi: 10.1016/j.scitotenv.2022.153517. Epub 2022 Jan 29.
The invasion of Spartina alterniflora poses a serious threat to the sustainability of native ecosystems worldwide. However, compared with other non-native plants (e.g., Phragmites australis and Kandelia obovata), how Spartina alterniflora invasion influences the community structure of bacteria and their assembly processes and functionality remains elusive. Here, we characterized the diversity, community structure, assembly processes and functional guilds of bacteria underneath five plant species and a bare tidal flat at three soil depths in an estuarine wetland. We found that plant species played a more important role than soil depth in mediating the bacterial community structure. Compared with bare tidal flats, the native species Cyperus malaccensis, rather than Scirpus triqueter, significantly changed the bacterial community structure. However, S. alterniflora invasion increased bacterial alpha diversity and significantly altered the bacterial community structure by enriching Chloroflexi, Bacteroidetes and Firmicutes while reducing Acidobacteria, Nitrospirae and Gemmatimonadetes. The invasion of P. australis and translocation of K. obovata had less pronounced effects on the bacterial community structure. Total carbon, total nitrogen and salinity were the key environmental factors mediating the bacterial community structure. Overall of all the non-native plant species, the invasion of S. alterniflora increased the relative importance of stochastic processes in the assembly of bacterial communities, and shifted the bacterial functional profiles by stimulating sulfur cycling groups and suppressing nitrogen cycling groups. Altogether, our results suggest that S. alterniflora invasion has a greater effect than P. australis invasion or K. obovata translocation on the profiles and assembly processes of the bacterial communities, with important implications for soil biogeochemical processes in coastal wetlands.
互花米草的入侵对全球原生生态系统的可持续性构成了严重威胁。然而，与其他非本地植物（如芦苇和秋茄）相比，互花米草入侵如何影响细菌群落结构及其组装过程和功能仍不清楚。在这里，我们对河口湿地中三种土壤深度下的五种植物和一个裸露潮滩下的细菌多样性、群落结构、组装过程和功能类群进行了表征。我们发现，在介导细菌群落结构方面，植物物种比土壤深度发挥着更重要的作用。与裸露潮滩相比，本地物种短叶茳芏而非三棱藨草显著改变了细菌群落结构。然而，互花米草入侵增加了细菌的α多样性，并通过富集绿弯菌门、拟杆菌门和厚壁菌门，同时减少酸杆菌门、硝化螺旋菌门和芽单胞菌门，显著改变了细菌群落结构。芦苇的入侵和秋茄的移栽对细菌群落结构的影响较小。总碳、总氮和盐度是介导细菌群落结构的关键环境因素。总体而言，在所有非本地植物物种中，互花米草的入侵增加了随机过程在细菌群落组装中的相对重要性，并通过刺激硫循环类群和抑制氮循环类群改变了细菌功能谱。总之，我们的结果表明，互花米草入侵对细菌群落的分布和组装过程的影响比芦苇入侵或秋茄移栽更大，这对沿海湿地的土壤生物地球化学过程具有重要意义。
