Chin J Plan Ecolo ›› 2016, Vol. 40 ›› Issue (3): 187-199.DOI: 10.17521/cjpe.2015.0343

Special Issue: 青藏高原植物生态学:群落生态学

• Research Articles •     Next Articles

Effects of clipping and fertilization on the temporal dynamics of species diversity and functional diversity and their relationships in an alpine meadow

Bin-Bin KONG1, Xin-Hua WEI1, Jia-Li DU1, Ying-Nian LI2, Zhi-Hong ZHU1,*()   

  1. 1College of Life Sciences, Shaanxi Normal University, Xi’an 710119, China

    2Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining 810008, China
  • Received:2015-09-08 Revised:2016-02-06 Online:2016-04-11 Published:2016-03-25
  • Contact: Zhi-Hong ZHU

Abstract: Aims

Strong disturbance and environment stress have significant influence on species diversity (SD) and functional diversity (FD) in plant community. However, the changes in SD, FD and their relationships over time remain controversial. Previous studies showed that the SD-FD relationship along disturbance gradients can represent positive correlation, negative correlation and/or sigmoid curve, respectively. Our aim here is to explore the temporal dynamics patterns of SD and FD in a community experienced disturbance. Particularly, we explored how specific disturbance factor and/or disturbance intensity affect the SD-FD relationship over time.

Methods

The experiment was conducted in the alpine Kobresia humilis meadow at Haibei Research Station of the Chinese Academy of Sciences with clipping (unclipping, stubbled 3 cm and 1 cm) and fertilizing (12.75 g·m-2·a-1 urea + 3.06 g·m-2·a-1 ammonium phosphate) treatments from 2007 to 2013. GLMRMANOVA regression analysis and ANCOVA were used for analyzing the effects of different treatment factors and their interaction on SD, FD, the patterns of temporal dynamics of SD and FD and their relationship over time.

Important findings

SD and FD significantly increase with increasing clipping intensity. In contrast, fertilization decreased SD and increased feebly FD. During the experiment period, SD declined with time while FD increased. The SD-FD relationship was positively correlated in unclipped and moderate clipped plots, but was not correlated in heavy clipped plots. The slope of SD(x)-FD(y) relationship declined with the increase in clipping intensity. In contrast, fertilization did not change the shape and slope of the SD(x)-FD(y) relationship. The effects of the interaction of clipping and fertilization on SD and FD were not significant, and the slope changes along clipping gradients were identical in fertilized and unfertilized plots. These results suggest that clipping disturbance may induce trait divergence rather than trait convergence in this meadow community, while the strong interspecific competition resulted from fertilizing may not significantly intensify the trait divergence. These findings were inconsistent with the predictions of plant community assembly theory. Compared with fertilizing disturbance, clipping disturbance should play a more important role in shaping the SD-FD relationship.

Key words: clipping, fertilization, plant functional traits, species diversity, functional diversity