Chin J Plant Ecol ›› 2014, Vol. 38 ›› Issue (10): 1074-1081.DOI: 10.3724/SP.J.1258.2014.00101

Special Issue: 青藏高原植物生态学:群落生态学

• Research Articles • Previous Articles     Next Articles

Effects of fertilization and grazing on species richness in an alpine meadow of Qinghai-Xizang Plateau

YANG Zhong-Ling1,*(), SU Fang-Long1, MIAO Yuan1, ZHONG Ming-Xing1, XIAO Rui2,*()   

  1. 1School of Life Science, Henan University, Kaifeng, Henan 475000, China
    2College of Resources and Environmental Science, Nanjing Agricultural University, Nanjing 210000, China
  • Received:2014-01-28 Accepted:2014-09-07 Online:2014-01-28 Published:2021-04-20
  • Contact: YANG Zhong-Ling,XIAO Rui


Aims Plant species diversity often declines when nutrients are added in grassland. However, the mechanisms for explaining biodiversity loss due to nutrient enrichment have remained controversial. Our objective was to explore the potential mechanisms of diversity decline.
Methods In this paper, based on a four-year experiment of nutrient addition and grazing in an alpine plant community, we investigate the potential mechanisms of diversity loss by comparing the above- and below-ground competitions using coefficient of variation and nitrogen use efficiency under fertilization scenario both in grazed and non-grazed plots.
Important findings Fertilization increased the size inequality of individuals by 15%, increased species height by different degrees, and reduced the number of species pairs that differed significantly in nitrogen content by 65% in the non-grazed plots. The results indicate that the large-sized individuals out-competed the small-sized individuals due to competition for light, which led to a decline in species richness by 29.6% in the non-grazed plots following fertilization. In contrast, fertilization did not change the size inequality of individuals and species height in the grazed plots, and increased the number of species pairs that differed significantly in nitrogen content by 11.4%, implying that an increased competition for soil nitrogen among species reduced the species richness by 17.3%. Our study also suggests that grazing delayed the effect of fertilization on species richness as inferred by the lower rate of species loss in the grazed plots.

Key words: alpine meadow, belowground competition, community ecology, light competition, size inequality, species richness