Chin J Plant Ecol ›› 2009, Vol. 33 ›› Issue (3): 499-507.DOI: 10.3773/j.issn.1005-264x.2009.03.009

• Research Articles • Previous Articles     Next Articles

RESPONSE OF PLANT SPECIES COMPOSITION AND COMMUNITY STRUCTURE TO LONGTERM GRAZING IN TYPICAL STEPPE OF INNER MONGOLIA

YANG Hao1, BAI Yong-Fei1,*(), LI Yong-Hong2, HAN Xing-Guo1   

  1. 1State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
    2New Zealand Institute for Crop & Food Research Limited, Private Bag 4704, Christchurch, New Zealand
  • Received:2008-09-03 Accepted:2008-12-20 Online:2009-09-03 Published:2009-05-31
  • Contact: BAI Yong-Fei

Abstract:

Aims We studied (a) spatial patterns in typical Leymus chinensis and Stipa grandis steppe communities along two grazing gradients and (b) changes in plant species composition and community structure over a 20-year period in Inner Mongolia, with the objective of understanding grazing-associated grassland dynamics.

Methods Grassland communities were investigated in 1985 and 2005 on 15 field sites, seven along a grazing gradient in S. grandis steppe and eight along a grazing gradient in L. chinensis steppe. Changes in spatial and temporal patterns of these steppe ecosystems were examined and analyzed in association with changes in land use intensity in the region.

Important findings For the S. grandis steppe, five of the seven sites showed a trend towards increas-ing dominance of S. grandis after 20 years, whereas the other two sites showed signs of degradation. For the L. chinensis steppe, six sites exhibited a trend towards restoration of community composition and structure and two sites displayed the reverse trend. Changes in spatial and temporal patterns in both S. grandis and L. chinensis successional communities were mainly due to a shift in grassland management regimes in 1985-2005. Long-term heavy grazing accelerated grassland degradation, and decreased grazing intensity promoted grassland restoration processes. During the past 20 years, especially after 2003, the change in grassland management policy has not resulted in overall grassland degradation in the region; rather it has brought about a more spatially balanced grassland use.

Key words: typical steppe, land use policy, succession, cluster analysis, aboveground biomass, species richness, species composition