Variation in Near-Surface Airborne Bacterial Communities among Five Forest Types

• Main Authors: Jianbo Fang, Qiyu Dong, Weijun Shen, Xiaoling Liu, Ning Dou, Lihua Xian, Hongyue Chen
• Format: Article
• Language: English
• Published: MDPI AG 2020-05-01
• Series: Forests
• Subjects: airborne bacteria; 16S rRNA; soil physicochemical properties; vegetation; microclimate
• Online Access: https://www.mdpi.com/1999-4907/11/5/561

Airborne bacteria play important roles in air pollution, human health and biogeochemical cycles. However, their spatial variation and determinant factors in forest environments are poorly understood. In this study, we selected five forest types in the Liuxihe National Park, South China, to analyze how near-surface bacterial community structure is related to the forest community structure and soil physicochemical properties. The results indicated that the dominant communities were mainly constituted by seven bacterial genera of the phyla Proteobacteria (49.7%–55.4%) and Firmicutes (44.2%–49.8%), including <i>Exiguobacterium</i> (42.0%–46.4%),<i> Citrobacter </i>(20.7%–25.8%),<i> Acinetobacter</i> (20.1%–22.1%), and<i> Pseudomonas</i> (7.8%–8.9%) etc. However, differences in the composition and diversity of the airborne bacterial communities were evident among the five forests, especially with respect to the dominant taxa. The relative abundance of <i>Enterococcus</i> and <i>Bacillus</i> in coniferous and broad-leaved mixed forest (MF), broad-leaved mixed forest (BF), and pure <i>Cunninghamia</i> <i>lanceolata</i> forest (CL) was significantly higher than that of the other forests, while the relative abundance of <i>Citrobacter</i> was significantly lower. The relative abundance of <i>Citrobacter</i>, <i>Acinetobacter,</i> and <i>Pseudomonas</i> in Proteobacteria were significantly negatively correlated with plant diversity and acid phosphatase activity but positively correlated with soil pH and soil available potassium. Contrastingly, the correlation between the relative abundance of most genera of Firmicutes and the above environmental factors is just the opposite of that for Proteobacteria. We provide direct evidence that native plant communities in the middle stage of succession, compared to planted forests and forest open space, generally had higher airborne bacterial diversity. Airborne bacterial diversity showed a significantly positive correlation with plant diversity (<i>p</i> < 0.05). Over all, soil pH, soil available potassium, and soil available phosphorus contributed to a high rate of the diversity of the airborne bacterial community in near-surface, followed by the plant diversity of the arbor layer and the near-surface air temperature. These results extended our understanding of the ecological patterns of airborne bacteria in forest ecosystems.