Diversity of butterflies in different habitat types of Seethawaka wet zone botanic gardens and Indikadamukalana forest reserve of Sri Lanka

Abstract

Botanic gardens, forest reserves and other protected areas are established to conserve biodiversity. The present study was conducted to assess the butterfly diversity in a recently established botanic garden of Sri Lanka, the Seethawaka Wet Zone Botanic Gardens (SWZBG) and Indikadamukalana Forest Reserve (IMFR) adjacent to the garden. Three different habitat types within the botanic gardens, the undisturbed forest habitat within the forest reserve and the buffer zone between the Botanic Gardens and Forest Reserve were investigated for butterflies. Butterfly species richness, diversity, endemic species, family composition in different habitats and effects of habitat parameters on butterfly distribution were assessed. Butterflies were collected from five habitats – grassland, shrub, disturbed forest, undisturbed forest, buffer zone, of the SWZBG and IMFR using transect line method with hand netting and fruit baited traps. Collected butterflies were identified using published field guides. Climate and soil parameters of each habitat were measured using standard methods and equipment. Differences of habitat parameters between habitats were estimated using One-Way Analysis of Variance and Tukey’s Multiple Comparison method and butterfly diversity and evenness in different habitat types were assessed using Shannon-Weiner diversity index. The study revealed seventy-nine butterfly species from SWZBG and IMFR highlighting the importance of the sites for safeguarding and conservation of butterflies. Species richness and diversity of butterflies was highest in the buffer zone and lowest in the grassland habitat. The most common butterfly family in the study sites was family Nymphalidae. Endemic species were high in the forest habitat types. Significant differences were evident in habitat parameters between habitat types indicating their effect on butterfly species richness and diversity. The study revealed SWZBG and IMFR as important areas for butterfly occurrence when compared with similar botanic gardens and forest reserves elsewhere in the world.