Spatial Variation in Butterfly Diversity Along the Gaula River, Haldwani, Kumaun Himalaya, India

This study examines spatial variation in the Gaula River riparian region, Haldwani, Uttarakhand. We divided a 10 km stretch into 7 sub-sites and conducted the study over 2 years (March 2022- April 2024). Researchers used the Pollard Walk method to record 108 butterfly species from 6 families, 23 subfamilies, and 73 genera. Nymphalidae was the most dominant family (48 species), and Riodinidae was the least dominant (3 species). Among all sites, Site 5 recorded the highest species richness (94 spp.) and abundance (2406 individuals), with Simpson’s Diversity Index of 0.9706 and Shannon-Wiener Diversity Index of 3.919. In contrast, Site 2 had the lowest species richness (23 species) and abundance (277 individuals), with a Simpson’s Diversity Index of 0.9078 and a Shannon-Wiener Diversity Index of 2.613. Species Accumulation Curves (SACs) showed sampling adequacy, and the stabilisation of the curves indicates a valid sample size. Nymphalidae and Pieridae were the dominant butterfly families. Sites 5, 1, and 4 clustered together and exhibited higher abundance. In contrast, Sites 2 and 6 clustered together and exhibited lower overall butterfly abundance. Of 108 species, 7 were recorded across all 7 sites, while 8 species had highly specialised distributions, restricted to a single study site. These specialised species could serve as ecological indicators and thus be useful for monitoring butterfly population dynamics from a conservation perspective.