Chin J Plant Ecol ›› 2014, Vol. 38 ›› Issue (5): 440-451.DOI: 10.3724/SP.J.1258.2014.00040

• Research Articles • Previous Articles     Next Articles

Plastic responses of stem and leaf functional traits in Leymus chinensis to long-term grazing in a meadow steppe

LI Xi-Liang1,2,HOU Xiang-Yang1,*(),WU Xin-Hong1,null null1,JI Lei1,CHEN Hai-Jun1,LIU Zhi-Ying1,2,DING Yong1,*()   

  1. 1Institute of Grassland Research, Chinese Academy of Agriculture Sciences, Hohhot 010010, China
    2Graduate School of Chinese Academy of Agriculture Sciences, Beijing 100081, China
  • Received:2013-12-26 Accepted:2014-02-17 Online:2014-12-26 Published:2014-05-13
  • Contact: HOU Xiang-Yang,DING Yong

Abstract:

Aims Adaptation of plants to their habitats through phenotypic plasticity in which they trade off various kinds of functional traits is an important ecological strategy. Whereas plant functional traits and its effects on grassland ecosystem functioning have received much attention, the importance of grazing effects on functional traits is poorly understood. This study, therefore, aimed to analyze the responding model of Leymus chinensis functional traits to long-term grazing in semi-arid grassland.
Methods The study was conducted in a field experiment involving treatments with various grazing and enclosure schemes in Nei Mongol. We compared the effects of long-term enclosure, short-term enclosure (SE), moderate grazing (MG), and heavy grazing on plant functional traits in L. chinensis. Partial Least Squares Regression was used to analyze the contributions of controlling factors on changes in biomass in response to grazing.
Important findings The size of L. chinensis became smaller in plots subject to long-term grazing compared with in the plots of enclosures. It had a significant conservative property of plant dwarf which can be found in the SE plot. Interestingly, the variability increased significantly with the increasing of plasticity index of different functional traits. Also, some functional traits, such as aboveground biomass, plant height, mean leaf length etc., were sensitive traits to grazing. However, other indicators, such as leaf numbers, stem diameter, mean leaf width etc., which were inert functional traits. Stem length, plant height and other traits were main factors which cased the decreasing of L. chinensis aboveground biomass. On the whole, phenotypic change is an important adaptive strategy of L. chinensis to long term grazing.

Key words: functional trait, Leymus chinensis, meadow steppe, overgrazing, phenotypic plasticity, plant dwarf of grassland