Variations of Soil Microbial Community Structures Beneath Broadleaved Forest Trees in Temperate and Subtropical Climate Zones.

Sihang Yang,Caiyun Yang,Tong Yuan,Hui Lu,Baohua Gu,Jing Cong,Mengxin Zhao,Diqiang Li,Yuguang Zhang,Jizhong Zhou,Mengmeng Wang,Yunfeng Yang,Changyi Xie

doi:10.3389/fmicb.2017.00200

Abstract

Global warming has shifted climate zones poleward or upward. However, understanding the responses and mechanism of microbial community structure and functions relevant to natural climate zone succession is challenged by the high complexity of microbial communities. Here, we examined soil microbial community in three broadleaved forests located in the Wulu Mountain (WLM, temperate climate), Funiu Mountain (FNM, at the border of temperate and subtropical climate zones), or Shennongjia Mountain (SNJ, subtropical climate). Although plant species richness decreased with latitudes, the microbial taxonomic α-diversity increased with latitudes, concomitant with increases in soil total and available nitrogen and phosphorus contents. Phylogenetic NRI (Net Relatedness Index) values increased from -0.718 in temperate zone (WLM) to 1.042 in subtropical zone (SNJ), showing a shift from over dispersion to clustering likely caused by environmental filtering such as low pH and nutrients. Similarly, taxonomy-based association networks of subtropical forest samples were larger and tighter, suggesting clustering. In contrast, functional α-diversity was similar among three forests, but functional gene networks of the FNM forest significantly (P < 0.050) differed from the others. A significant correlation (R = 0.616, P < 0.001) between taxonomic and functional β-diversity was observed only in the FNM forest, suggesting low functional redundancy at the border of climate zones. Using a strategy of space-for-time substitution, we predict that poleward climate range shift will lead to decreased microbial taxonomic α-diversities in broadleaved forest.

Highlights

The ecological effects of global warming have widely been documented, with range shifts toward the poles at the rate of averagely 6.1 km per decade, and mean advancement of spring events by 2.3 days per decade (Camille and Gary, 2003)
FNM is located in Henan Province, the boundary of temperate and subtropical climate zones
A total of 24 environmental factors were measured, which could be classified as climatic, aboveground vegetation and soil geochemical factors (Supplementary Table S1)

Summary

Introduction

The ecological effects of global warming have widely been documented, with range shifts toward the poles at the rate of averagely 6.1 km per decade, and mean advancement of spring events by 2.3 days per decade (Camille and Gary, 2003). The taxonomic α-diversity decreased with latitudes (Supplementary Table S2), and microbial OTU compositions differed significantly (P < 0.005) among three forests based on three nonparametric statistical tests of adonis, MRPP and anosim (Table 1). DCA showed that samples of WLM, FNM and SNJ forests were well-separated from each other (Supplementary Figure S1A).

Results

Conclusion