Pointpattern analysis of Hedysarum laeve population in Mu Us sandy land
LIU Fa, Yang-Hai-Long, Gao-Jia-Rong, Cui-Jiang, Li-Bai
1. Key Lab. of Soil & Water Conservation and Desertification Combating, Ministry of Education,Beijing Forestry University, 100083, Beijing; 2. Yanchi Desert Ecosystem Research Station of Ningxia, Beijing Forestry University 751500, Yanchi ,Ningxia:China
Abstract：Hedysarum laeve is an important and widely planted sand fixation plant in north China arid region. Population pattern of this specie is studied with the method of point pattern analysis. Two 50m×50m typical sample plots with different aerieal seeding periods were selected as research sites in Mu Us sandy land, Ningxia Province. As to the analysis method, Ripley’s K function bivariate point pattern was performed to find the space correlation between the plants. The results show that: space distribution pattern of Hedysarum laeve depends on two factors, individual sizes and environments. Along with the increase of plant size, Hedysarum laeve is more likely to follow clumped distribution. The spatial association between plants will turn from negative correlation to positive correlation if their size differences are diminished. Unlike the Hedysarum laeve plants growing in fixed sandy land，those plants in semifixed sandy land are easier to follow clumped distribution and associate with each other positively．If Hedysarum laeve plants are transplanted into shifting sandy land for sand control and vegetation restoration，they ought to be arranged in the form of clumped distribution rather than regular distribution.
2011, Vol. 9 
