Nitrogen enrichment modifies plant community structure via changes to plant–soil feedback
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We tested the hypothesis that N enrichment modifies plant–soil feedback relationships, resulting in changes to plant community composition. This was done in a two-phase glasshouse experiment. In the first phase, we grew eight annual plant species in monoculture at two levels of N addition. Plants were harvested at senescence and the effect of each species on a range of soil properties was measured. In the second phase, the eight plant species were grown in multi-species mixtures in the eight soils conditioned by the species in the first phase, at both levels of N addition. At senescence, species performance was measured as aboveground biomass. We found that in the first phase, plant species identity strongly influenced several soil properties, including microbial and protist biomass, soil moisture content and the availability of several soil nutrients. Species effects on the soil were mostly independent of N addition and several were strongly correlated with plant biomass. In the second phase, both the performance of individual species and overall community structure were influenced by the interacting effects of the species identity of the previous soil occupant and the rate of N addition. This indicates that N enrichment modified plant–soil feedback. The performance of two species correlated with differences in soil N availability that were generated by the species formerly occupying the soil. However, negative feedback (poorer performance on the soil of conspecifics relative to that of heterospecifics) was only observed for one species. In conclusion, we provide evidence that N enrichment modifies plant–soil feedback relationships and that these modifications may affect plant community composition. Field testing and further investigations into which mechanisms dominate feedback are required before we fully understand how and when feedback processes determine plant community responses to N enrichment.
KeywordsNitrogen deposition Decomposition Soil community Nutrient availability Plant competition
This work was funded by the UK Natural Environment Research Council via the CPB. We thank the Ecotron support staff and Dina Koulama for their assistance. The experiments described in this paper complied with the laws of the United Kingdom at the time the experiments were performed.
- Anon (2007) Integrated taxonomic information system. http://www.itis.usda.gov.index.html
- Jones TH, Thompson LJ, Lawton JH, Bezemer TM, Bardgett RD, Blackburn TM, Bruce KD, Cannon PF, Hall GS, Hartley SE, Howson G, Jones CG, Kampichler C, Kandeler E, Ritchie DA (1998) Impacts of rising atmospheric carbon dioxide on model terrestrial ecosystems. Science 280:441–443PubMedCrossRefGoogle Scholar
- Manning P, Newington JE, Robson HR, Saunders M, Eggers T, Bradford MA, Ellis RJ, Gange AC, Marhan S, Kandeler E, Tscherko D, Reid E, Grayston SJ, Bonkowski M, Bardgett RD, Godfray HCJ, Rees M (2006) Decoupling the direct and indirect effects of nitrogen deposition on ecosystem function. Ecol Lett 9:1015–1024PubMedCrossRefGoogle Scholar
- Pinheiro JC, Bates DM (2000) Mixed-effects models in S and S-PLUS. Springer, New YorkGoogle Scholar
- Rodwell JS (2000) British plant communities, volume 5, maritime communities and vegetation of open habitats. Cambridge University Press, CambridgeGoogle Scholar
- Tilman D (1988) Plant strategies and the dynamics and structure of plant communities. Princeton University Press, PrincetonGoogle Scholar
- Venables WN, Ripley BD (2002) Modern applied statistics with S. Springer, New YorkGoogle Scholar
- Vitousek PM, Aber JD, Howarth RW, Likens GE, Matson PA, Schindler WH, Schleslinger WH, Tilman DG (1997) Human alteration of the global nitrogen cycle: sources and consequences. Ecol Appl 7:737–750Google Scholar
- Wardle DA (2002) Communities and ecosystems: linking the aboveground and belowground components. Princeton University Press, PrincetonGoogle Scholar