Fruit-feeding butterfly communities on Mt. Nimba, Liberia, are structured by habitat and elevation 

The Mount Nimba region of Liberia is one of West Africa’s most significant biodiversity hotspots, supporting over 600 butterfly species within a complex mosaic of lowland evergreen forests, submontane forests, and high-altitude edaphic savannah. Despite its global conservation importance as a UNESCO World Heritage Site and Key Biodiversity Area, the Nimba Mountains face escalating pressure from iron ore mining operations. In addition, climate change is expected to alter seasonal patterns in temperature and rainfall, potentially disrupting butterflies' ability to track shifting habitat quality. This study aims to describe how fruit-feeding butterfly communities are structured by elevation, habitat, and season. Field sampling was conducted between February 2024 and January 2025 using Van Someren-Rydon traps baited with fermented banana. The traps were deployed across six transects: at three different elevations, a primary forest and a savannah habitat were sampled for six days per month. A total of 3,876 fruit-feeding butterflies representing 131 species were recorded across the six transects. Forest transects yielded substantially higher abundance and species richness than savannah transects. Shannon diversity was also highest in forest habitats. Community composition differed markedly between habitats. Forest transects were dominated by specialists in the subfamily Satyrinae, while savannah transects were characterised by various widespread open-habitat species. In addition, some species shifted seasonally between habitats. Abundance and species richness tended to peak at intermediate elevation, and the community composition was also affected by elevation. We observed strong temporal variation. These results suggest that deforestation will lead to diverse communities being replaced by few widespread species at this West African mountain. This study was funded by the National Science Centre, NCN, Poland (2021/43/B/NZ8/00966).