The butterflies of Ngazidja and their main habitats significances

Abstract

Ngazidja, the biggest island of Comoros, is characterized by the higher level of endemism that is threatened by the rapid habitat degradation. This study was carried out to investigate the butterfly fauna of the forests of the Karthala (North and North-eastern slopes) and La Grille (Eastern slopes) in order to help the biodiversity conservation and protection. Transect counts were carried out to assess the endemicity, abundance and species richness of four zones of studies from 500m elevation. Natural forest, regenerated forest, plantation and grasslands were covered. 48 species in 5 families were observed and the distribution demonstrated to be influenced by the sites’ elevation and the vegetation. The remains slots of natural forest at higher altitude shelters had higher abundance of endemicity but lower specific richness in contrast to plantation habitat that housing the biggest number of endemic species with lower abundance. Relatively common and migratory butterflies were mainly abundant in the open areas, where human activities intended to increase the variety of plants. The long term survival of this fauna and vegetation depends on one another. We argue that it is proper time to set longtime plans to conserve and protect areas of Comoro islands into action, with conservation strategies taking account the global endemicity and richness in all habitats.