关键词: 南岭, 植被类型, 土壤微生物, 群落, 环境因子

Abstract: Soil microorganisms are the most species-rich group in terrestrial ecosystems and serve as crucial bioindicators for assessing soil quality and ecosystem health. We investigated soil microbial community structure and function under dry season five typical vegetation types (ravine evergreen broad-leaved forest, montane evergreen broad-leaved forest, mixed coniferous-broad-leaved forest, montane meadow, montane elfin forest) in Nanling. Utilizing high-throughput sequencing technology, combined with redundancy analysis and Mantel test methods, we explored soil microbial diversity and the influencing factors. The results showed that the phylum Acidobacteria had the highest relative abundance of bacteria, accounting for 40.2%-49.7%, followed by Proteobacteria (28.3%-36.9%) and Actinobacteria (5.9%-8.4%). The relative abundance of Acidobacteria was highest in the montane meadow, while Proteobacteria was most abundant in the ravine evergreen broad-leaved forest. The genus candidatus Solibacter was most prevalent in the montane evergreen broad-leaved forest and lowest in the montane elfin forest. Ascomycota (11.9%-71.9%) and Basidiomycota (19.2%-84.3%) were the dominant fungal groups. Basidiomycota predominated in the ravine evergreen broad-leaved forest and montane evergreen broad-leaved forest, whereas Ascomycota was dominant in the mixed coniferous-broad-leaved forest, montane meadow, and montane elfin forest. At the genus level, Russula was the dominant fungal genus in ravine evergreen broad-leaved forest and montane evergreen broad-leaved forest. Chemoheterotrophy was the primary functional group for bacteria, with an average proportion of 65.3%, being higher in the ravine evergreen broad-leaved forest and montane elfin forest but lower in mixed coniferous-broad-leaved forest. For fungi, symbiotrophic and saprotrophic nutritional modes were the main functional groups, with average proportions of 46.1% and 43.5%, respectively. Symbiotrophic fungi were more abundant in the ravine evergreen broad-leaved forest and montane evergreen broad-leaved forest, while saprotrophic fungi were more prevalent in the mixed coniferous-broad-leaved forest, montane meadow, and montane elfin forest. Soil pH, total nitrogen, and total potassium were the main factors influencing bacterial communities, whereas altitude, ammonium, and nitrate were the primary factors affecting fungal communities. Altitude, ammonium, and total phosphorus were identified as key drivers of the spatial variation in soil microbial diversity under typical vegetation types in the Nanling region during the dry season.

Key words: Nanling Mountains, vegetation type, soil microorganism, community, environmental factor