Study on Restoration Succession of Plant Community in Degenerated Leymus chinensis Steppe after Harrowing for Thirty Years
The study was conducted at Inner Mongolia Grassland Ecosystem Research Station of the Chinese Academy of Sciences in Xilingol Region to provide scientific basis for the restoration succession of degenerated Leymus chinensis grassland after harrowing for thirty years.The results showed that during the restoration succession for 30 years,community composition increased firstly and then decreased.The increase of community composition was due to the invasion of the annual or biannual forbs during the early treatment,the decrease of community composition attributed to annual or biannual forbs gradually replaced by the perennial gramineae plants in the free competition.Community density rose firstly and then declined sharply and finally was gradually stable.The rising of community density attributed to that gramineae plants occupied more niche by proliferation,the stable community density was due to the smooth and steady succession after fierce competition.Community species diversity and evenness both decreased firstly and then was gradually stable.The decrease of community species diversity and evenness attributed to the gradual increase of dominance of gramineae plants,the stable community species diversity and evenness was due to that the population structure tended to be stable after fierce competition.Degenerated steppe of Leymus chinensis restoration succession progress for 30 years can be divided into four stages:the first stage was a community of A.frigid+L.chinensis+Lower bunch grass (1 year after harrowing),the second stage was a community of L.chinensis+ A.cristatum+ annual or biannual forbs (2～3years after harrowing),the third stage was a transitional community of L.chinensis+ A.cristatum+perennial forbs (4～22 years after harrowing),the forth stage was a community of L.chinensis+ S.grandis + bunch grass (23～30 years after harrowing).
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万方数据
维普
