0023-6152

AA00697606

23767

査読無

0023-6152

AA00697606

The distributional pattern appearing with the population change of Microtus montebelli was examined in a very small restricted area of Mt. Hitome in the northern Kyushu. In native grassland, the places damaged intensely by the vole exhibited a patchy distribution bounded clearly by the uninjured area. In a grid established on the young plantation, the distribution of the points of capture was contagious and uneven during the growth phase (from December 1975 to April 1976), and the contagion was proved by Morisita's Iδ-index. Afterwards (from June 1976 of the peak phase to October 1976 of the beginning of the declining phase), the points showed a tendency to spread over the greater part except the part of the shrubs growing at the northwest of the grid. In the growing population, the vole was strongly sedentary, and there appeared frequently males with a placid temper. Accordingly, it seems likely that less agonistic behavior and reduction of the home range in the growing population result in the contagious distribution with the unusual high population density. Also, the population with the contagion of the vole's own property, the so-called “Great families”, appeared to consist of one to several families.