Abstract
Spatial pattern of live-shoot biomass of individual plant species was observed in two sown grasslands differing in their species composition to clarify the relationships between dominance and spatial heterogeneity of each species. Three surveys were carried out. In each survey, one hundred 50 cm×50 cm quadrats were arranged along a straight-line 50m long in a grassland, and the plants within each quadrat were harvested at a height of 3cm above the ground surface. The harvested samples were separated into live shoots based on species and whole dead shoots to measure the dry weight. The spatial heterogeneity of the respective materials was evaluated using p, one of the parameters of gamma distribution. The main results were as follows: (1) the live-shoot biomass of most species was distributed spatially more heterogeneously than in a random expectation, and the only two most dominant species exhibited a low heterogeneous pattern ;(2) Spatial heterogeneity for individual species showed a strong negative correlation with the degree of dominance; and (3) The total aboveground biomass, total live-shoot biomass and dead-shoot biomass showed a less heterogeneous pattern than in a random case although the live-shoot biomass of each species exhibited a strong heterogeneous pattern.
