Plant and Soil

, Volume 338, Issue 1, pp 483–495

Effects of plant species richness and evenness on soil microbial community diversity and function

Authors

    • Department of Plant SciencesUniversity of Saskatchewan
  • Nabla Kennedy
    • Ecosystem Science and Management ProgramUniversity of Northern British Columbia
  • Steven D. Siciliano
    • Department of Soil ScienceUniversity of Saskatchewan
Regular Article

DOI: 10.1007/s11104-010-0560-6

Cite this article as:
Lamb, E.G., Kennedy, N. & Siciliano, S.D. Plant Soil (2011) 338: 483. doi:10.1007/s11104-010-0560-6

Abstract

Understanding the links between plant diversity and soil communities is critical to disentangling the mechanisms by which plant communities modulate ecosystem function. Experimental plant communities varying in species richness, evenness, and density were established using a response surface design and soil community properties including bacterial and archaeal abundance, richness, and evenness were measured. The potential to perform a representative soil ecosystem function, oxidation of ammonium to nitrite, was measured via archaeal and bacterial amoA genes. Structural equation modeling was used to explore the direct and indirect effects of the plant community on soil diversity and potential function. Plant communities influenced archaea and bacteria via different pathways. Species richness and evenness had significant direct effects on soil microbial community structure, but the mechanisms driving these effects did not include either root biomass or the pools of carbon and nitrogen available to the soil microbial community. Species richness had direct positive effects on archaeal amoA prevalence, but only indirect impacts on bacterial communities through modulation of plant evenness. Increased plant evenness increased bacterial abundance which in turn increased bacterial amoA abundance. These results suggest that plant community evenness may have a strong impact on some aspects of soil ecosystem function. We show that a more even plant community increased bacterial abundance, which then increased the potential for bacterial nitrification. A more even plant community also increased total dissolved nitrogen in the soil, which decreased the potential for archaeal nitrification. The role of plant evenness in structuring the soil community suggests mechanisms including complementarity in root exudate profiles or root foraging patterns.

Keywords

Plant–soil interactionStructural equation modelingCommunity structureEcosystem function

Supplementary material

11104_2010_560_MOESM1_ESM.doc (182 kb)
ESM 1Supplementary methods and figures detailing the relationships between mesocosm plant community composition and plant species richness, evenness, density, functional group composition, and harvest plant evenness. Supplementary tables include variable ranges and transformations, detailed structural equation model results, and variance–covariance matrices of the data reported in this paper. (DOC 182 kb)
11104_2010_560_MOESM2_ESM.xls (88 kb)
ESM 2A spreadsheet containing the raw data and accompanying metadata used in this study is also provided. (XLS 87 kb)

Copyright information

© Springer Science+Business Media B.V. 2010