Proposed Multipurpose Project at Pancheshwar in the Western Himalaya affects rich butterfly diversity: a conservation concern

The Pancheshwar Multipurpose Project proposed for the construction of the largest dam in South Asia is located in the biodiversity rich fragile landscape of the Indian Himalayan Region. In the present scenario, the area at Pancheshwar is being perturbed and going through forest clearance on a regular basis for pre-dam construction operations such as tunnel, road building etc. Butterflies that are vital and crucial organisms for the functioning of terrestrial ecosystems get drastically affected by such large changes in their habitats. The present study therefore aims at describing the importance of butterfly conservation with respect to their diversity and composition along different habitat conditions prevailing at the main dam site of Pancheshwar in the Western Himalaya. Previously, the rich biological diversity of butterflies had remained relatively unknown from the region. By adopting the standardized sampling techniques during 2016–2018, a total of 5341 individuals of 98 species under six butterfly families were recorded from the five representative habitat types (sampling sites) with varying degrees of disturbance. The area was found to be enriched with 23.27% of the known species from the Western Himalaya. Based on global distribution 72.44% of the total recorded species were of the Oriental region, 10.20% species showed Palaearctic distribution while seven species were endemic to the Himalaya. Moreover, the richness and abundance of butterflies varied significantly among the habitat types under various threat levels. The highly disturbed habitat (a forest area altered for pre-dam constructions which was formerly covered with canopy) yielded least diversity and richness while the forest edge habitat in a moderately degraded forest showed the highest diversity, richness and uniqueness, rendering it as a key habitat for preservation and conservation of butterflies. The other three sites selected in the riparian zone had the high similarity of butterfly assemblages. A total of 28 butterfly species were identified on the utmost conservation priorities based on their national protection status, diet specialization, local and global geographic distributions. The high diversity and heterogeneity in community composition is attributed to complex vegetation and diverse habitat conditions prevailing in a fairly isolated geographical area proposed for the mega dam construction. IMPLICATIONS FOR INSECT CONSERVATION: At present, declines in the both quality and type of habitats due to the heedless on-going dam construction related activities are causing adverse affects on the rich butterfly diversity and posing paramount threats of habitat loss and extinction to butterfly fauna that include many rare, specialist, legally protected and endemic species of the fragile Himalayan ecosystem. This study thus substantiates the need for adoption of timely specified, decisive and effective conservation practices in such regions of prime biological importance.