Effects of land management on species composition of butterflies and nectar resources in a semi-natural grassland near Mt. Fuji, central Japan

Abstract

We investigated the effects of land management on species composition of plants and nectar flowers, butterflies in a semi-natural grassland at the foot of Mt. Fuji in central Japan. The study area included five site types with different vegetation structures and management regimes: (1) firebreaks where grass was mowed and removed, (2) Larix kaempferi plantation areas where grass was mowed alone, (3) unpaved roads with mowed banks, (4) abandoned grassland, and (5) scrub forest. In these sites, the largest number of annual plant species was found in the firebreaks, while woody plant species were more abundant in the plantations and the road areas. The smallest number of perennial plant species was found in the scrub. A two-way indicator species analysis divided the species composition of plants and nectar flowers into the scrub and the other sites, and secondarily, the firebreaks and the mowed areas, the road areas, and the abandoned grassland. The flowering season of indicator species of nectar flowers was July for the firebreaks, and August and September for the other sites. On the other hand, butterfly species composition in the firebreaks differed from all the other sites, and the indicator species in the firebreaks appeared in July, suggesting that butterfly species composition is affected by flowering season of nectar plants in this grassland. Moreover, the shrub species in the scrub were host plants for the larvae of certain butterfly species. These results indicate that butterfly diversity can be maintained by the diverse management regimes and vegetation structures in grasslands.