This study investigated butterfly communities in riparian zones adjacent to dams, comparing agricultural (AG) and non-agricultural (NAG) areas. From April to October 2024, biweekly butterfly surveys were conducted using a standardized line transect method across three dam regions in Jeollanam-do, South Korea. NAG sites consistently showed higher species richness and total abundance than AG sites, although these differences were not statistically significant. Extrapolated diversity estimates indicated variations between the two areas, except for species richness. Seasonal patterns of species richness and abundance differed between land-use types. Rank-abundance distribution analysis revealed that NAG areas had more even species distributions, best described by the Log-normal model, while AG areas exhibited steep dominance patterns consistent with the Zipf-Mandelbrot model. The five most dominant species comprised 73.4% of individuals in AG sites, compared to just 51.4% in NAG sites. NMDS ordination illustrated distinct community clustering between NAG and AG sites, though PERMANOVA and MRPP did not identify statistically significant group differences. These findings suggest that reduced disturbance and greater habitat heterogeneity in NAG areas promote more resilient and balanced butterfly communities. The study emphasizes the ecological importance of natural riparian zones and highlights the potential of butterfly assemblages as indicators for biodiversity monitoring and conservation planning.

The Pieris napi-complex in East Asia that comprises P. melete Ménétriés, 1857, P. dulcinea (Butler 1882), and P. nesis (Fruhstorfer 1909) has been taxonomically challenging to distinguish due to their similar appearances. In this study, P. nesis, typically found in central Japan, was discovered in the highlands on Jejudo Island, the southernmost part of the Korean Peninsula. We conducted a molecular phylogenetic analysis using mitochondrial COI gene to explore the relationship between P. dulcinea and P. nesis, and confirmed that P. nesis occurs in Korea. This paper provides the morphological characteristics of P. nesis compared to P. dulcinea, along with DNA data.