Box-Counting Dimensions of Spatial Distribution Pattern of Ceratoides ewersmanniana and Haloxylon ammodendron Populations in Southern Rim of Gurbantunggut Desert,Xinjiang

Ceratoides ewersmanniana and Haloxylon ammodendron were the edificators and dominant species in the Gurbantunggut Desert,playing an important role in wind breaking and sand fixing.Box-counting dimension method of the fractal theory was used in comparative analysis of spatial distribution of the populations of the two shrub plants in two sample plots(200 m×200 m),different in type of habitat.Results of the analysis indicate that the box-counting dimension of spatial distribution of the population of C.ewersmanniana was 1.709 and 1.527 0 in plot A and B,respectively,and of H.ammodendron,1.406 3 and 1.568 6,respectively.All in all,the former was comparatively higher than the latter in capability of occupying and exploiting space.The box-counting dimension of interspecies spatial distribution of the two shrub plants varied slightly between Plot A and Plot B,being 1.780 5 and 1.735 7,respectively,both higher than the box-counting dimension of spatial distribution of the population of a single species,which suggests that when deemed as a whole,C.ewersmanniana and H.ammodendron populations were much higher in capability of occupying and exploiting space,and their ecological functions was similar in either Plot A or B.