BIODIVERSITY AND COMMUNITY STRUCTURE OF TEMPERATE BUTTERFLY SPECIES WITHIN A GRADIENT OF HUMAN DISTURBANCE - AN ANALYSIS BASED ON THE CONCEPT OF GENERALIST VS SPECIALIST STRATEGIES

We monitored nine butterfly communities with varying degrees of human disturbance by conducting a census twice a month during 1980 by the li ne transect method in and around Tsukuba City, central Japan. We analy zed the biodiversity and community structures using the generalist/spe cialist concept. The site (community) order based on decreasing human disturbance was positively correlated with butterfly species diversity (H'), species richness (the total number of species), and the number of specialist species in a community, but not with the number of gener alist species. The number of generalist species was rather constant, i rrespective of the degree of human disturbance. Thus, both the butterf ly species diversity and species richness were more dependent on the s pecialists than the generalists. Our analyses also showed that the gen eralist species were distributed widely over the communities, and they maintained high population densities, resulting in high rank status i n abundance in a community, with more spatial variation in density per species. Specialist species showed the opposite trends. These results demonstrate that the generalist/specialist concept is a powerful tool applicable to analyse the biodiversity and structure of natural commu nities.