Distinct soil bacterial communities along a small-scale elevational gradient in alpine tundra

Abstract

The elevational diversity pattern for microorganisms has received great attention recently but is still understudied, and phylogenetic relatedness is rarely studied for microbial elevational distributions. Using a bar-coded pyrosequencing technique, we examined the biodiversity patterns for soil bacterial communities of tundra ecosystem along 2000–2500 m elevations on Changbai Mountain in China. Bacterial taxonomic richness displayed a linear decreasing trend with increasing elevation. Phylogenetic diversity and mean nearest taxon distance (MNTD) exhibited a unimodal pattern with elevation. Bacterial communities were more phylogenetically clustered than expected by chance at all elevations based on the standardized effect size of MNTD metric. The bacterial communities differed dramatically among elevations, and the community composition was significantly correlated with soil total carbon (TC), total nitrogen, C:N ratio, and dissolved organic carbon. Multiple ordinary least squares regression analysis showed that the observed biodiversity patterns strongly correlated with soil TC and C:N ratio. Taken together, this is the first time that a significant bacterial diversity pattern has been observed across a small-scale elevational gradient. Our results indicated that soil carbon and nitrogen contents were the critical environmental factors affecting bacterial elevational distribution in Changbai Mountain tundra. This suggested that ecological niche-based environmental filtering processes related to soil carbon and nitrogen contents could play a dominant role in structuring bacterial communities along the elevational gradient.

Contrasting elevational diversity patterns for soil bacteria between two ecosystems divided by the treeline

“…Similarly, Wang et al revealed a hollow elevational diversity pattern of fungi in Tibet related to soil pH (Wang et al, 2015b). The monotonically decreasing diversity pattern in the grassland was consistent with a recent study in tundra where soil carbon and nitrogen were considered as the limiting factors (Shen et al, 2015).…”

“…Ding et al also demonstrated soil temperature as the main factor influencing microbial composition around the timberline (Ding et al, 2015). Total variation explained by soil temperature combined with available phosphorus, pH, and clay content reached 67% in the meadow, implying niche-based environmental filtering processes strongly structuring bacterial communities along the elevational gradient (Shen et al, 2015). However, the explanatory power of bacterial diversity in the forest is much lower than that in the meadow.…”

Interannual Variability of Soil N and C Forms in Response to Snow—Cover duration and Pedoclimatic Conditions in Alpine Tundra, Northwest Italy

“…5). The mean DOC (from 238 to 474 mg kg -1 ) recorded in our research site was comparable to that reported by Shen et al (2015) (~400 mg kg -1 ) in the Qinghai-Tibetan Plateau. The mean DON (from 11.7 to 24.6 mg kg -1 ) was on the same order of magnitude as that observed by Gao et al (2015) (13.9 mg kg -1 ) (Fig.…”

“…The mean N micr (from 52.5 to 160 mg kg -1 ) was comparable to that observed by Williams et al (2007), but higher than that reported by Hood et al (2003) (from ~9 to 27 mg kg -1 ) for the Colorado Rockies, and the C micr had values comparable or higher than other alpine and arctic areas (Fig. 7) (e.g., Edwards and Jefferies, 2013;Shen et al, 2015). To date, according to our knowledge, with the exception of works about the interannual changes in CO 2 fluxes in both alpine (e.g., Saleska et al, 1999;Kato et al, 2006) and arctic tundra (e.g., Harazono et al, 2003), very little is known about the interannual variability of soil N and C forms in alpine tundra soils.…”

Local Environmental Factors Drive Divergent Grassland Soil Bacterial Communities in the Western Swiss Alps

“…Furthermore, the soil composition can change over an elevation gradient due to the geological and/or land use history of mountain areas, giving each mountain ecosystem a unique geochemical profile that shapes the local endemic bacterial communities. For instance, the soil bacterial communities along the Changbai Mountain in China were driven by the soil total carbon and nitrogen, the C:N ratio, and dissolved organic carbon, which changed across the elevation strata (19), whereas in the Colorado Rockies, soil pH and elevation were strongly negatively correlated with each other (3). Elevational differences may also relate to human impact, as was shown in a study by Marini and coworkers (20) on the effect of farm size in the Italian Alps.…”