Niche Dynamics of Dominant Species during the 30 Years Restoration Process of Natural Grassland in Yunwu Mountain
In order to explore the niche dynamics of dominant species during 30 years restoration process of natural grassland in Yunwu Mountain,the ecological niches of the main species in different enclosure years were calculated using Levin's and Pianka's indices,based on the field survey data got by “quadrat method”.Results showed that the species composition and community types differed among the grasslands of different enclosure years.The niche breadths of Heteropappus altaicus,Stipa grandis,Potentilla bifurca and Thymus mongolicus,which appeared in the grasslands of five treatments,were larger than that of other species.Stipa bungeana that used to be a dominant species of Yunwu Mountain with large niche breadth was not found in the quadrats of 30 year enclosure grassland.The species with largest niche breadth in grasslands of enclosure 5-year,9-year,14-year,18-year and 30-year were Stipa bungeana,Artemisia gansuensis,Artemisia scoparia,Stipa grandis and Stipa grandis,respectively.The niche breadth of dominant species fluctuated with the increase of enclosure years.The niche breadth of Stipa grandis showed “up-down-up” trend along with the increasing of enclosure years.The niche breadth of Stipa bungeana initially declined then increased after 18 year enclosure.The niche breadth of Stipa przewalskyi,which appeared only in 30-year enclosure plots,ranked only second to Stipa grandis.There was no a linear relationship between the niche overlap and niche breadth of tested species in the grasslands at different enclosure years.The average value of niche overlap indices was the largest in 9-year enclosure grassland.The grassland ecosystem was gradually restored with long time enclosure.Meanwhile,interspecific competition was also increased.
NETL
NSTL
万方数据
维普
