Shift of Dominant Species in Plant Community and Soil Chemical Properties Shape Soil Bacterial Community Characteristics and Putative Functions: A Case Study on Topographic Variation in a Mountain Pasture.

Myung-Hyun Kim,Soon-Kun Choi,Min-Kyeong Kim,Jinu Eo

doi:10.3390/microorganisms9050961

Myung-Hyun Kim, Soon-Kun Choi + Show 2 more

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https://doi.org/10.3390/microorganisms9050961

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Abstract

Reducing management intensity according to the topography of pastures can change the dominant plant species from sown forages to weeds. It is unclear how changes in species dominance in plant community drive spatial variation in soil bacterial community characteristics and functions in association with edaphic condition. Analysing separately the effects of both plant communities and soil chemical properties on bacterial community is crucial for understanding the biogeographic process at a small scale. In this paper, we investigated soil bacterial responses in five plant communities (two forage and three weed), where >65% of the coverage was by one or two species. The structure and composition of the bacterial communities in the different microbiome were analysed using sequencing and their characteristics were assessed using the Functional Annotation of Prokaryotic Taxa (FAPROTAX) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. Firmicutes and Planctomycetes responded only to one specific plant community, and each plant community harboured unique operational taxonomic units (OTUs) at the species level. There were a large percentage of uniquely absent OTUs for specific plant communities, suggesting that a negative effect is critical in the relationship between plants and bacteria. Bacterial diversity indices were influenced more by soil chemical properties than by plant communities. Some putative functions related to C and N recycling including nitrogen fixation were correlated with pH, electrical conductivity (EC) and nutrient levels, and this also implied that some biological functions, such as ureolysis and carbon metabolism, may decline when fertilisation intensity is reduced. Taken together, these results suggest that a shift of dominant species in plant community exerts individual effects on the bacterial community composition, which is different from the effect of soil chemical properties.

Highlights

Introduction published maps and institutional affilMountain pastures have been developed for agricultural purposes due to the intensification of lowland farming
Decreasing management intensity causes spatial variation in the soil chemical properties accompanied by vegetation succession [2]
The electrical conductivity (EC) was significantly higher in P. pratensis than in S. miyabei × S. salicifolia, and the concentrations of NO3 − and available P tended to be lower in S. miyabei × S. salicifolia

Summary

Introduction

Mountain pastures have been developed for agricultural purposes due to the intensification of lowland farming. These pasture habitats are subject to abandonment and decreased management due to their intensive labour requirements and for economic reasons [1]. Decreasing management intensity causes spatial variation in the soil chemical properties accompanied by vegetation succession [2]. Plant communities dominated by single or a few species may be formed due to changes in resource availability [5]. Pasture vegetation is mainly comprised of a few forage species and the substitution of dominant species greatly influences ecosystem processes at a local scale [6]

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