モニタリンこよるノコギリモク群落の分布様式の解析

摘要

Sargassum macrocarpum (Fucales, Phaeophyta) is a perennial brown alga and forms dense populations called Sargassum beds. The beds play a major role in primary production in coastal ecosystems, and are important as nursery grounds for coastal fishes and other animals. This review focused on moni-toring data of the dispersion of individuals in the S. macrocarpum population on a flat rock area at the depth of about 8 m in Fukawa Bay, facing the Sea of Japan, Yamaguchi Prefecture, Japan. In the present study, the distribution patterns were analyzed using Morisita's Jo index. The patterns of individuals in the population in October 1993 had a random distribution. But, the young thalli under 2 years old and the adult thalli more than 3 years old had contagious and regular distribution, respectively. After that, the distributional patterns of individuals changed from random distribution to contagious distribution with the process of "gap regeneration" in the S. macrocarpum population.