Chin J Plant Ecol ›› 2022, Vol. 46 ›› Issue (2): 176-187.DOI: 10.17521/cjpe.2021.0397

• Research Articles • Previous Articles     Next Articles

Diversity-productivity relationship of plant communities in typical grassland during the long- term grazing exclusion succession

ZHANG Yi1,2, CHENG Jie3, SU Ji-Shuai4, CHENG Ji-Min1,2,5,*()   

  1. 1Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling, Shaanxi 712100, China
    2University of Chinese Academy of Sciences, Beijing 100049, China
    3Key Laboratory of National Forestry Administration on Ecological Hydrology and Disaster Prevention in Arid Regions, Northwest Surveying, Planning and Designing Institute of National Forestry and Grassland Administration, Xi’an 710048, China
    4State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
    5Institute of Soil and Water Conservation, College of Grassland Agriculture, Northwest A&F University, Yangling, Shaanxi 712100, China
  • Received:2021-11-04 Accepted:2022-01-18 Online:2022-02-20 Published:2022-01-25
  • Contact: CHENG Ji-Min
  • Supported by:
    National Key R&D Program of China(2016YFC0500700);Chinese Academy of Sciences Field Station Alliance Project(KFJ-SW-YW028-07)

Abstract:

Aims Grazing exclusion is an important intervention for restoring degraded grasslands. Understanding the changes of grassland productivity and plant diversity during the long-term grazing exclusion succession, as well as the relationship between diversity and productivity, are helpful for grassland restoration management and utilization.

Methods This study was conducted in a typical grassland system with a long-term grazing exclusion gradient, located at Yunwu Mountain National Nature Reserve in Ningxia Huizu Autonomous Region. The grassland communities under continuous grazing, 9 years of grazing exclusion, 26 years of grazing exclusion, and 34 years of grazing exclusion were chosen as the study objects. We tracked changes in aboveground net primary productivity (ANPP), species diversity and functional diversity, and quantified the relationships between diversity and productivity.

Important findings The results showed that grazing exclusion significantly increased ANPP, litter biomass, functional richness, and functional dispersion of typical grassland, but did not alter species richness, Shannon- Wiener index and functional evenness. In contrast, Simpson dominance index and Pielou evenness index significantly decreased after long-term grazing exclusion (34 years). In addition, grazing exclusion showed diverse effects on community-weighted means of different functional traits. The results of random forest model and variance partition analysis indicated that community-weighted mean functional traits accounted for 70.70% of ANPP variation, and plant height was identified as the most important trait. Functional diversity explained 36.86% of ANPP variation, mainly contributed by functional richness. In contrast, species diversity only explained 14.72% of ANPP variation. Therefore, the contribution of mean trait values and functional diversity to ANPP was much higher than that of species diversity in grassland after grazing exclusion. We suggest that community mean trait values and functional diversity should be incorporated into the studies of plant community dynamics during restoration succession, which will contribute to a comprehensive understanding of the relationship between plant diversity and ecosystem function, and provide basis for better realization of ecological restoration goals.

Key words: functional diversity, plant functional trait, species diversity, grazing exclusion, aboveground net primary productivity