Butterfly assemblages of forest, grassland and disturbed ecotones near Goba, southern Mozambique

Abstract

Transect surveys of adult butterflies and diurnal moths were conducted at seven study sites in Goba-Maputo, southern Mozambique. Four hundred and fifty individuals representing 83 Lepidoptera species were recorded. Species composition and ecological indices (similarity, richness, dominance and diversity) were calculated for total and specialist species. Forest, with more than 80% canopy cover with height grater than 2 meters has the lowest species richness. Three species were restricted to forest. Grasslands showed greater canopy cover for the vegetation less than 0.5 meter high, and ranked second on lepidopteran species diversity. The forest edges with more than 50% of canopy cover of a mixture of middle-sized trees, between 1 and 2 m, has the highest species richness. Charaxes candiope was the dominat species in the study area. However Hamanumida daedalus, Bicyclus safitza safitza, Charaxes jasius saturns na Catacrotera cloanthe cloante were the most dominante species in Apiario grassland (G), Mandimbe edge (E), Mbilambi fores (F) and Movene grassland (G). Grassland and forest edges shred more species than forest and disturbed forest edge. Most forest species avoided forest edges and/or grassland indicating that they are probably more sensitive to fragmentation and edges. Thus, the results show that fragmentation generally increase species diversity (forest edges contained the greatest species richness.) However in the long term, habitat disruption can reduce overall species diversity, reducing species with low geographic ranges and forest endemics, whilst gaining generalist species. For conservation purpose core areas of the forest should be preserved, a measure which would protect other (uncensored) species.