Soil bacterial communities at the treeline in subtropical alpine areas

• Published in: Catena (Giessen) 2021-06, Vol.201, p.105205, Article 105205
• Main Authors: Lin, Yu-Te, Whitman, William B., Coleman, David C., Jien, Shih-Hao, Wang, Hsueh-Ching, Chiu, Chih-Yu
• Format: Article
• Language: English
• Subjects: Alpine soil; Forest; Grassland; Pyrosequencing; Treeline soil
• ISSN: 0341-8162; 1872-6887
• DOI: 10.1016/j.catena.2021.105205

[Display omitted] •Vegetation differences caused changes in soil properties among sites.•Differences in soil properties influenced the bacterial community structure.•Present vegetation at the treeline influences soil bacterial community structure.•Historical changes in vegetation had legacy effects on certain bacterial groups. As a temperature-sensitive transition zone, the subtropical alpine region responds quickly to global warming. However, little is known about soil microbial communities at the treeline, where changes in vegetation in response to global warming are anticipated. Barcoded pyrosequencing of the 16S rRNA gene was used to investigate the bacterial communities of coniferous forest and grassland soils at the treeline of four different peaks above 3,000 m a.s.l. Although the forest soils were more acidic than the grassland soils, the other soil properties were highly variable with no consistent pattern in C and N contents and microbial biomass between two vegetation types. The Acidobacteria and α-Proteobacteria were the most abundant phylogenetic groups, although their relative abundances differed among the forest and grassland soil communities and between sites. The composition of bacterial communities or β-diversity, varied significantly between the sites and vegetation types. In contrast, α-diversity only differed significantly between sites. Two of the grassland sites and one forest had converted from forests and grassland, respectively within the last 60 years. The abundances of some genera, such as Acidobacteria Gp2 in the grasslands converted from forests, more closely resembled those of the other forest sites than the historically grassland sites, while the abundance of Acidobacteria Gp1 in the forest converted from grassland was more similar to the historically grassland sites. These results suggest a legacy effect for the transition of forest to grassland. Bacterial community structure also correlated significantly with soil pH, organic C and C/N. These results suggest that the present vegetation at the treeline influences soil bacterial community structure, although there is also a significant legacy effect on the abundance of certain bacterial groups.