Journal of Ecology and Conservation

ABSTRACT

The Ibisbill (Ibidorhyncha struthersii) is a rare, habitat-specialist wader dependent on undisturbed riverine ecosystems in Asia’s high-altitude and mid-hill regions. This study examined the wintering ecology and habitat factors influencing Ibisbill abundance in the Rapti– Khulekhani III–Samari (RBS) River Complex in Makwanpur, central Nepal. Standardized 3 km transect surveys were conducted along the Rapti, Khulekhani III, and Samari rivers from November 2024 to March 2025. A total of 24 individuals were recorded, with the highest mean density observed in Khulekhani III (6 birds/km²), followed by Rapti (2 birds/km²) and Samari (1 bird/km²). One-way ANOVA revealed significant variation in density across sites (F = 8.33, p = 0.005), and Tukey’s HSD post-hoc test confirmed a significantly greater density in Khulekhani III compared to the other rivers. The species exhibited a clumped distribution pattern (S²/r̄=7), indicating aggregation in localized, suitable habitats. These habitats were characterized by native riverine grassland dominated by Saccharum spontaneum and Imperata cylindrica. Linear regression analysis revealed that human disturbance, sand extraction, and habitat fragmentation negatively influenced Ibisbill abundance, while native riverine grass cover and greater distance from settlements had significant positive effects. Elevation was not a significant predictor. These results highlight the ecological importance of the River Complex and underscore the need for targeted conservation actions. Effective protection of Ibisbill wintering habitat should prioritize the regulation of sand extraction, reduction of anthropogenic disturbance, and promotion of community-based conservation. Sustained monitoring and habitat management are critical to ensure the long-term survival of this habitat-specialist wader in Nepal’s mid-hill river systems.

KEYWORDS

1. Ibisbill
2. Riverine habitat
3. Riverine grassland
4. Ecology