Spartina alterniflora invasion alters soil microbial community composition and microbial respiration following invasion chronosequence in a coastal wetland of China.

Wen Yang,Shuqing An,Xin Leng,Xiaoli Cheng,Nasreen Jeelani

doi:10.1038/srep26880

Abstract

The role of exotic plants in regulating soil microbial community structure and activity following invasion chronosequence remains unclear. We investigated soil microbial community structure and microbial respiration following Spartina alterniflora invasion in a chronosequence of 6-, 10-, 17-, and 20-year-old by comparing with bare flat in a coastal wetland of China. S. alterniflora invasion significantly increased soil moisture and salinity, the concentrations of soil water-soluble organic carbon and microbial biomass carbon (MBC), the quantities of total and various types of phospholipid fatty acids (PLFAs), the fungal:bacterial PLFAs ratio and cumulative microbial respiration compared with bare flat. The highest MBC, gram-negative bacterial and saturated straight-chain PLFAs were found in 10-year-old S. alterniflora soil, while the greatest total PLFAs, bacterial and gram-positive bacterial PLFAs were found in 10- and 17-year-old S. alterniflora soils. The monounsaturated:branched PLFAs ratio declined, and cumulative microbial respiration on a per-unit-PLFAs increased following S. alterniflora invasion in the chronosequence. Our results suggest that S. alterniflora invasion significantly increased the biomass of soil various microbial groups and microbial respiration compared to bare flat soil by increasing soil available substrate, and modifying soil physiochemical properties. Soil microbial community reached the most enriched condition in the 10-year-old S. alterniflora community.

Highlights

The role of exotic plants in regulating soil microbial community structure and activity following invasion chronosequence remains unclear
The highest salinity and the lowest water-soluble organic carbon (WSOC) were found in 20-year-old S. alterniflora soil, while the greatest soil organic C (SOC) concentration was found in 17-year-old S. alterniflora soil (Table 1)
Our findings added to various evidence that S. alterniflora invasion greatly accelerated soil organic C and N accumulation due to greater biomass input[14,29] (Table 1), and found that S. alterniflora invasion significantly increased microbial biomass carbon (MBC) concentration and the quantities of the total and all types of phospholipid fatty acids (PLFAs) compared with bare flat soil (Figs 1–3)

Summary

Introduction

The role of exotic plants in regulating soil microbial community structure and activity following invasion chronosequence remains unclear. Alterations in plant community structure may affect composition of soil microbial community and functioning by altering the quality and quantity of litter input and by modifying soil physical, chemical and biological environment[5]. Many invasive plants are considered to be more decay resistant owing to their higher levels of lignins, tannins, and other secondary compounds[12], and lower quality of invasive plant materials (higher carbon (C)/nitrogen (N) ratio of litter and/or root)[14] These invasive plants are the cause of higher soil C:N ratios relative to the native ecosystem[16]. The changes in the soil substrates and physicochemical properties altogether affect the soil microbial community structure and activity following plant invasion in a chronosequence

Methods

Results

Conclusion