Effects of Plant Functional Group Loss on Soil Microbial Community and Litter Decomposition in a Steppe Vegetation.

Chunwang Xiao,Fan Yang,Yong Zhou,Jiaqi Su

doi:10.3389/fpls.2017.02040

Abstract

Globally, many terrestrial ecosystems are experiencing a rapid loss of biodiversity. Continued improvements in our understanding of interrelationships between plant diversity and soil microbes are critical to address the concern over the consequences of the decline in biodiversity on ecosystem functioning and services. By removing forbs, or grasses, or, to an extreme scenario, both forbs and grasses in a steppe vegetation in Inner Mongolia, we studied how plant functional group (PFG) loss affects soil microbial community composition using phospholipid fatty acid analysis (PLFA) and litter decomposition using a litter-bag method. PFG loss significantly decreased above- and below-ground plant biomass, soil microbial biomass carbon (SMBC) and nitrogen (SMBN), but had no effect on the ratio of SMBC to SMBN. Although the ratio of fungal to bacterial PLFAs remained unaffected, PFG loss significantly reduced the amount of bacterial, fungal, and total PLFAs. PFG loss decreased litter monthly mass loss and decay constant, and such decrease was significant when both forbs and grasses were removed. Our results provide robust evidence that PFG loss in grassland ecosystem can lead to a rapid response of soil microbial activity which may affect litter decomposition and soil nutrient cycling, suggesting that the assessment of plant–microbe interactions in soils is an integral component of ecosystem response to biodiversity loss.

Highlights

Species composition and numbers in terrestrial ecosystems are being modified by anthropogenic activities, generating concerns that ecosystem functioning and services would be affected by this unprecedented loss of biodiversity (Tilman, 2000; Jenkins, 2003; Reich et al, 2012; Tilman et al, 2014)
In addition to the potential alteration of organic resources, species/plant functional group (PFG) loss modifies soil environmental conditions that indirectly affect the behavior of soil microorganisms (Lorentzen et al, 2008), representing additional challenges to unveil the interrelationships between plant diversity and soil microbial communities
The overall objective of this study is to assess the effect of PFG loss on soil microbial community composition and litter decomposition rate

Summary

Introduction

Species composition and numbers in terrestrial ecosystems are being modified by anthropogenic activities, generating concerns that ecosystem functioning and services would be affected by this unprecedented loss of biodiversity (Tilman, 2000; Jenkins, 2003; Reich et al, 2012; Tilman et al, 2014). Some experimental studies have indicated that plant species loss leads to decreased soil microbial biomass (Eisenhauer et al, 2010), abundance and functional diversity of bacterial or fungal (Zak et al, 2003; Lamb et al, 2011; Chen et al, 2016), whereas many others have reported that responses of soil microbial communities to plant diversity/richness are insensitive (Orwin and Wardle, 2005; Loranger-Merciris et al, 2006; Berg and Smalla, 2009). In addition to the potential alteration of organic resources, species/PFG loss modifies soil environmental conditions that indirectly affect the behavior of soil microorganisms (Lorentzen et al, 2008), representing additional challenges to unveil the interrelationships between plant diversity and soil microbial communities

Objectives

Methods

Results