Root trait-mediated belowground competition and community composition of a temperate steppe under nitrogen enrichment
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Shifts of plant community composition with enhanced atmospheric nitrogen (N) deposition in grasslands have occurred globally. Despite extensive studies on the effects of enhanced N deposition on plant species composition of grassland community, few studies have focused on belowground ecological processes and duration of N addition.
In situ long-term (14-year: 2004–2017) and short-term (4-year: 2014–2017) N-addition experiments in the same sites were conducted in a temperate steppe of northern China. We investigated the effects of N-addition on plant community composition and root traits by comparing results of short-term and long-term N addition.
Nitrogen-evoked changes in plant community composition were primarily dependent on N-addition duration and functional groups. Short-term N addition favored growth of grasses, and depressed growth of forbs, while long-term N addition favored growth of sedges, and concurrently depressed growth of grasses and forbs, ultimately leading to a time-dependent shift of plant community composition from co-dominance by grasses and forbs to dominance by grasses, then to dominance by sedges. Similar to the observed aboveground biomass, short-term N addition led to an increase in the relative belowground biomass (the proportion of belowground biomass of individual plant to community belowground biomass) of the grass Stipa krylovii and a decrease in the relative belowground biomass of the forb Artemisia frigida, respectively. In contrast, long-term N addition enhanced the relative belowground biomass of the sedge Carex korshinskyi, and reduced the relative belowground biomass of the grass S. krylovii and the forb A. frigida. Moreover, traits of absorptive fine roots (first-two orders) in the three species (grass: S. krylovii; forb: A. frigida; sedge: C. korshinskyi) that are representatives of three functional groups differed in their responses to short-term and long-term N addition, thus rendering them differentially competitive for acquisition of belowground resource. The changes in root traits of the three species in responses to N addition of varying duration were associated with their relative aboveground biomass.
Root traits play important roles in mediating the competition for belowground resource and changes in plant community composition of temperate grasslands under N enrichment. Our findings provide novel insights into N-deposition-induced changes in steppe community composition by linking root traits of functional groups and duration of N addition.
KeywordsNitrogen deposition Community dynamics Functional groups Inner Mongolia steppe
We thank Weile Chen from Pennsylvania State University Michigan State University, Amandine Erktan from University of Goettingen, and Zeqing Ma from Institute of Geographic Sciences and Natural Resources Research of Chinese Academy of Sciences for thoughtful comments on earlier version of the manuscript. This work was supported by National Natural Science Foundation of China (31830011 and 31470466).
- Bobbink R, Hicks K, Galloway J, Spranger T, Alkemade R, Ashmore M, Bustamante M, Cinderby S, Davidson E, Dentener F, Emmett B, Erisman JW, Fenn M, Gilliam F, Nordin A, Pardo L, De Vries W (2010) Global assessment of nitrogen deposition effects on terrestrial plant diversity: a synthesis. Eco Appl 20:30–59CrossRefGoogle Scholar
- Eshel A, Beeckman T (2013) Plant roots: the hidden half, Fourth edn. CRC press, Taylor & Francis Group, New YorkGoogle Scholar
- Fang Y, Xun F, Bai WM, Zhang WH, Li LH (2012) Long-term nitrogen addition leads to loss of species richness due to litter accumulation and soil acidification in a temperate steppe. PLoS ONE 7:e4736. https://doi.org/10.1371/journal.pone.0047369
- Freschet GT, Valverde-Barrantes OJ, Tucker CM, Craine JM, McCormack ML, Violle C, Fort F, Blackwood CB, Urban-Mead KR, Iversen CM, Bonis A, Comas LH, Cornelissen JHC, Dong M, Guo D, Hobbie SE, Holdaway RJ, Kembel SW, Makita N, Onipchenko VG, Picon-Cochard C, Reich PB, de la Riva EG, Smith SW, Soudzilovskaia NA, Tjoelker MG, Wardle DA, Roumet C (2017) Climate, soil and plant functional types as drivers of global fine-root trait variation. J Ecol 105:1182–1192CrossRefGoogle Scholar
- Garnier E, Stahl U, Laporte M-A, Kattge J, Mougenot I, Kühn I, Laporte B, Amiaud B, Ahrestani F, Bönisch G, Bunker DE, Cornelissen JHC, Díaz S, Enquist BJ, Gachet S, Jaureguiberry P, Kleyer M, Lavorel S, Maicher L, Pérez-Harguindeguy N, Poorter H, Schildhauer M, Shipley B, Violle C, Weiher E, Wirth C, Wright LJ, Klotz S (2016) Towards a thesaurus of plant characteristics: an ecological contribution. J Ecol 105:298–309CrossRefGoogle Scholar
- Harpole WS, Sullivan LL, Lind EM, Firn J, Adler PB, Borer ET, Chase J, Fay PA, Hautier Y, Hillebrand H, MacDougall AS, Seabloom EW, Williams R, Bakker JD, Cadotte MW, Chaneton EJ, Chu C, Cleland EE, D'Antonio C, Davies KF, Gruner DS, Hagenah N, Kirkman K, Knops JM, La Pierre KJ, McCulley RL, Moore JL, Morgan JW, Prober SM, Risch AC, Schuetz M, Stevens CJ, Wragg PD (2016) Addition of multiple limiting resources reduces grassland diversity. Nature 537:93–96CrossRefGoogle Scholar
- Marschner H (2012) Mineral nutrition of higher plants. Academic Press, LondonGoogle Scholar
- R Development Core Team (2018) R: a language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria: R foundation for Statistical computingGoogle Scholar
- Simkin SM, Allen EB, Bowman WD, Clark CM, Belnap J, Brooks ML, Cade BS, Collins SL, Geiser LH, Gilliam FS, Jovan SE, Pardo LH, Schulz BK, Stevens CJ, Suding KN, Throop HL, Waller DM (2016) Conditional vulnerability of plant diversity to atmospheric nitrogen deposition across the United States. Proc Natl Acad Sci U S A 113:4086–4091CrossRefGoogle Scholar
- Tian Q, Liu N, Bai W, Li L, Chen J, Reich PB, Yu Q, Guo D, Smith MD, Knapp AK, Cheng W, Lu P, Gao Y, Yang A, Wang T, Li X, Wang Z, Ma Y, Han X, Zhang WH (2016) A novel soil manganese mechanism drives plant species loss with increased nitrogen deposition in a temperate steppe. Ecology 97:65–74CrossRefGoogle Scholar
- Tilman D (1988) Plant strategies and the dynamics and structure of plant communities. Princeton University Press, PrincetonGoogle Scholar
- Tilman D, Pacala S (1993) The maintenance of species richness in plant communities. Species diversity in ecological communities: historical and Geographyraphical perspectives (eds R.E. Ricklefs & D. Schluter). University of Chicago Press, ChicagoGoogle Scholar