Chin J Plant Ecol ›› 2013, Vol. 37 ›› Issue (11): 979-987.DOI: 10.3724/SP.J.1258.2013.00101

Special Issue: 生态化学计量

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Relationships between species diversity and C, N and P ecological stoichiometry in plant communities of sub-alpine meadow

CHEN Jun-Qiang1,ZHANG Rui1,HOU Yao-Chen1,MA Li-Na1,DING Lu-Ming2,LONG Rui-Jun1,SHANG Zhan-Huan1,*()   

  1. 1College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730020, China
    2School of Life Sciences, Lanzhou University, Lanzhou 730000, China
  • Received:2013-07-01 Accepted:2013-08-27 Online:2013-07-01 Published:2013-11-06
  • Contact: SHANG Zhan-Huan


Aims Our objective was to investigate relationships between species diversity of pasture and C, N and P stoichiometry characteristics of plants at the community level.
Methods This field survey focused on plant nutrient stoichiometry of two-level yields in alpine meadow in Eastern Qilian Mountain, China was conducted in early August 2012. Two survey sites were identified as high-yield grassland and low-yield grassland. At each survey site, two 8 m × 8 m plots were selected and divided into 64 1 m × 1 m subplots. For each subplot, the number of species was counted, and newly matured leaves were randomly selected after collecting the aboveground parts by clipping the plant at the soil surface. The collected leaves were sun-dried in the field and oven-dried at 80 °C to constant weight. All samples were finely ground and passed through a 40-mesh screen. Plant C concentration was analyzed by ash determination, plant N concentration was tested by Kjeldahl acid-digestion method and plant P concentration was analyzed by phosphorus vanadium molybdate yellow colorimetric method. Pearson’s bivariate correlation was used to test the relationship between plant C, N, and P stoichiometric traits and number of species. Two-tailed Student’s t-tests were used to compare plant stoichiometric variables.
Important findings Mean values of plant C, N and P concentrations in high-yield grassland were 53.05%, 1.99%, and 0.22%, respectively, and those in low-yield grassland were 52.51%, 2.28% and 0.19%, respectively. In high-yield grassland, the number of species was significantly positively correlated with plant N concentration and N:P ratio, while significantly negatively correlated with plant C:N ratio. In low-yield grassland, the number of species was significantly negatively correlated with N and P concentrations, but significantly positively correlated with C:N and C:P. Results indicated that the species of high-yield grassland were primarily limited by N concentration and positively correlated with N concentration. However, the species of low-yield grassland was co-limited by N and P concentrations and negatively correlated with N and P concentrations, thus indicating heterogeneity in C, N and P stoichiometry characteristics between high- and low-yield grasslands.

Key words: ecological stoichiometry, high-yield grassland, low-yield grassland, species diversity, sub-alpine meadow