Spatial analysis and niche overlap of two lapwing (Genus: Vanellus) species in the confluence of two biodiversity hotspots in South Asia.

Environmental factors play a critical role in shaping species distribution and resource utilization patterns. However, a gap of knowledge exists in understanding the niche dynamics between the two species; the ‘Least Concern’- Vanellus indicus (Red-wattled Lapwing) and the ‘Near Threatened’-Vanellus duvaucelii (River Lapwing), a difference that could prove critical for long-term conservation efforts. Thus, the present study aims to understand whether environmental variables influence their spatial patterns and examine the potential impact of niche overlap. Using primary and secondary species occurrence data, combined with environmental datasets, we modelled suitable habitats using an ensemble approach for each species with the SSDM package in R. Ensemble models performed well, yielding good predictive performance for both Vanellus indicus (AUC = 0.89) and Vanellus duvaucelii (AUC = 0.88). Predicted habitat areas for V. indicus were 28,818.35 km2 (high suitability), 23,101.29 km2 (moderate suitability), and 29,815.65 km2 (low suitability). For V. duvaucelii, these values were 12,429.95 km2, 26,452.24 km2, and 53,775.59 km2, respectively. Niche overlap, measured with Schoener’s D, was 0.55, indicating moderate similarity, with 0.07 and 0.04 representing unique niches for V. duvaucelii and V. indicus, respectively, and 0.96 of the being niches shared. These results underscore the ecological implications of niche sharing between overlapping species and highlight potential risks for V. duvaucelii, as overlapping habitats and limited niche exclusivity could increase vulnerability under rapidly changing environmental conditions. These findings further highlight the ecological consequences of niche sharing between the species and point out possible risks for V. duvaucelii, and thus poor niche separation may increase vulnerability under rapid environmental change.