INVESTIGATION OF PATTERN IN PLANT COMMUNITIES I. PATTERN IN CAREX KOBOMUGI OHWI POPULATION

抄録

1. Distributional pattern of the Carex kobomugi OHWI population in Hamasaka Sand Dune, Tottori, was investigated and the clump size of it was estimated by making use of MORISITA's Io_<(p)> index and the values of Io_<(s)>/Io_<(2s)>. 2. Individuals of ahoot were found to be distributed contagiously forming the clump, and two scales of pattern were found in this population. The scales of the pattern were about 1/32 and 1/2 square meters. 3. The correction method of the frequency distribution of clump size is described to remove the error based on the edge effect of quadrat. It is found that this method is of use with a reasonable degree of accuracy. 4. The smaller scale of clump size is ascribed to the mode of frequency distribution of clump size ; in other words, the primary scale of pattern shows the frequent or common clump size. The larger is due to the maximum total clump area, that is, it shows the maximum of the product of the number of clumps and the area of clump. The frequency distribution of the clump size of the population follows the lognormal distribution. As these two scales of pattern are determined in relation to the lognormal distribution, in such population that the frequency of clump size shows the lognormal form there may be two scales of pattern in any other species population. If the quadrat size is small, the secondary scale of pattern may not be found. 5. MORISITA's Is technique may be applied to the population which has not the normal frequency distribution of clump size.