Niche Partitioning Promotes Coexistence: Habitat Suitability and Spatial Overlap of Three Sympatric Ungulates in a Subtropical Mountain Reserve

Abstract

Understanding species–environment relationships and habitat overlap among sympatric ungulates is crucial for biodiversity conservation in mountainous ecosystems. Using a three-year camera-trap dataset (2021–2024) from Tongboshan National Nature Reserve, Jiangxi, China, we applied MaxEnt modeling to evaluate habitat suitability and niche overlap of Black muntjac (Muntiacus crinifrons), Reeves's muntjac (Muntiacus reevesi), and Wild boar (Sus scrofa). After spatial filtering, 103 independent occurrence records were analyzed against 12 environmental predictors representing topography, vegetation, soil, water, and anthropogenic disturbance. All models performed well (AUC > 0.90), with vegetation and topography contributing most to species distributions. Black muntjac exhibited a narrow spatial niche breadth, being strongly associated with mid- to high-elevation forests and close proximity to water sources, whereas Reeves's muntjac showed broad ecological flexibility, adapting to coniferous forests and moderately disturbed landscapes. Wild boar demonstrated generalist strategies, favoring forest edges and bamboo stands. Predicted suitable habitats covered 16.75%, 41.54%, and 31.17% of the reserve for Black muntjac, Reeves's muntjac, and Wild boar, respectively. Niche overlap analysis revealed the highest overlap between Reeves's muntjac and Wild boar (D = 0.822; I = 0.969), while Black muntjac showed limited overlap with either species. Species-specific habitat preferences and spatial partitioning emerge as key mechanisms enabling coexistence. We recommend prioritizing the maintenance of closed-canopy forest habitats for Black muntjac as the most critical conservation strategy, alongside enhancing forest heterogeneity in overlap zones and establishing ecological corridors to improve landscape connectivity. Our study provides quantitative evidence to guide adaptive management and support multi-species conservation in subtropical reserves.