Butterflies are weakly protected in a mega-populated country, Bangladesh

Abstract

Protected areas have been established around the world to preserve samples of biodiversity from pressing threats. Yet the adequacy of protected area systems in many tropical nations is poorly understood, and assessments are usually focused on vertebrates. Here, we model the occurrence of 246 butterfly species, and determine the extent to which they occur in protected areas in Bangladesh, a country that forms part of the Indo-Burma biodiversity hotspot. We develop ecological niche models, and measure overlap with protected areas using three methods to map species distributions (habitat suitability, area of occupancy, and extent of occurrence). Suitability maps identify the north-east and south-east regions as the main centres of butterfly diversity, yet there is marked variation among families, and between non-threatened and threatened species. Using the suitability map approach, a mean of 1.27% of the geographic range of species is covered by protected areas. Only two species (Euploea crameri and Danaus melanippus) have >15% coverage, 25% of species have no coverage and 70% of species have <1% coverage. Overall, protected area coverage is slightly higher for threatened species. Tracts of suitable, but unprotected habitat still exist in the north-east and south-east regions of Bangladesh, and designation of new protected areas in these regions will strengthen butterfly conservation in the country. Enhanced management of existing protected areas, and a strategy for conserving butterflies and other insects outside protected areas will also help secure the long-term future for biodiversity in Bangladesh.