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Acta Prataculturae Sinica ›› 2010, Vol. 19 ›› Issue (5): 239-249.

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The spatial distribution patterns of rare plant Gymnocarpos przewalskii communities in Subei

CHAI Yong-qing1,2, CAO Zhi-zhong1, CAI Zhuo-shan1, WAN Li-xia3, LI Xue-ling4   

  1. 1.College of Pratacultural, Gansu Agriculture University, Lanzhou 730070, China;
    2.Grassland
    Station of Subei County, Subei 736300, China;
    3.College of life Science of Northwest Normal
    University, Lanzhou 730070, China;
    4.College of Pastoral Agriculture Science
    and Technology, Lanzhou University, Lanzhou 730020, China
  • Received:2010-04-20 Online:2010-05-25 Published:2010-10-20

Abstract: In order to explore the spatial patterns of Gymnocarpos przewalskii in the Subei desert, as well as its causes and maintenance mechanisms, 60 quadrats are randomly set according to the vegetation types, the topography, geomorphology and the different altitudes. The variance/mean ratio, parameter of negative binominal, dispersal index, index of clumping, index of mean crowding, index of aggregation and index of patchiness, poisson distribution method are used to analyze the spatial distribution patterns and Kolmogogorov-Smirnov test for significance test. The results show that the population distributions of the G. przewalskii are contagious distribution at the dry beds of Gangou and One tree; taking on random distribution at the foreland dry bed areas of Lucaogou and Gangoukouzi, which is due to intense competition between middle-old plants against the background of their sexual reproductive decline and lack of seedlings; The intermediate type between random and contagious distribution at Yema River, which is due to the combined affect of intraspecies and interspecific competition, and the scouring of forceful deluge and mud-rock flow, coming close to contagious distribution at Jinmiaojing in Mazong mountain area, the reason of contagious distribution was related with its ecosystem environment. The seeds of G. przewalskii silted gradually in this area with eroding by flood and filling by silt because of which lies in puluvial fan plain. All of this caused the contagious distridution of G. przewalskii in the area.From the altitude standpoint, the population distributions of the G. przewalskii is weak contagious distribution at 1 500-1 550 m, random distribution at 2 400-2 450 and 2 450-2 500 m where mostly living from the Subei desert; the intermediate type between random and at 2 700-2 750 m. The spatial patterns of G. przewalskii in the Subei desert result from the major affect of its propagation characteristics and natural disaster, together with other factors, such as Human activity and environmental factors.

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