Soil Fungal Community Composition, Not Assembly Process, Was Altered by Nitrogen Addition and Precipitation Changes at an Alpine Steppe.

Yuanming Xiao,Yunfeng Peng,Changbin Li,Yuanhe Yang,Guoying Zhou,Yang Yang

doi:10.3389/fmicb.2020.579072

Abstract

Global climate change and nitrogen deposition have been having broad impacts on microorganisms. On the Qinghai-Tibetan Plateau (QTP), the responses of soil microbial community assemblage and diversity to nitrogen deposition and changes in precipitation are poorly understood, especially in the alpine steppe. In this study, we conducted a field manipulative experiment of nitrogen deposition and precipitation amount in an alpine steppe on the northeastern QTP and investigated the responses of community composition, diversity, and community assemblage of soil fungi. Soil fungal community compositions were significantly altered under nitrogen addition, precipitation change, and their interaction, and positively related with soil moisture, soil pH, and plant species richness. However, they were negatively related to soil mineralizable N and soil available P content. Operational taxonomic units (OTU) richness and Chao 1 index decreased under nitrogen addition combined with precipitation reduction treatment, whereas the Shannon–Wiener index declined only under precipitation increment treatment. Convergent fungal community assembly processes were not acutely altered by both nitrogen addition and precipitation changes, indicating that environmental filtering was a dominant ecological process controlling fungal community assemblage. By elucidating the above questions, the study enhanced our ability to predict the responses of soil fungal communities to nitrogen deposition and precipitation changes at alpine steppes on the QTP in the future.

Highlights

Dominant ecological processes controlling soil microbial community assemblage have attracted extensive attention (Dini-Andreote et al, 2015)
The Qinghai-Tibetan Plateau (QTP) is the largest and highest plateau in the world, and low temperature and strong evaporation are primary climatic features (Zheng and Zhao, 2017), which limit the rate of mineralization of soil organic matter and make this area more sensitive to global changes
It is important that the responses of soil fungal diversity, community composition, and assemblage process to nitrogen deposition and precipitation change are explored on the QTP

Summary

Introduction

Dominant ecological processes controlling soil microbial community assemblage have attracted extensive attention (Dini-Andreote et al, 2015). Global changes have broad and profound impacts on microbial communities (Hutchins et al, 2019); for example, Chen et al (2017) revealed that nitrogen addition enhanced the role of deterministic processes (i.e., environmental filtering) during soil arbuscular mycorrhizal fungal community assemblage in a temperate steppe. It is important that the responses of soil fungal diversity, community composition, and assemblage process to nitrogen deposition and precipitation change are explored on the QTP. We still poorly understand how soil fungal diversity, community composition, and assemblage process respond to nitrogen deposition, and relationships between fungal community composition and soil environmental variables remain to be unclear. Examining relationships between soil fungal community and plant diversity is important for comprehensively understanding the responses of soil fungal community to nitrogen deposition

Methods

Results

Conclusion