Distribution and richness of mammals in a tropical protected area of Bangladesh

Biodiversity loss continues to accelerate globally, with Protected Areas (PAs) serving as key tools for conservation. However, spatially explicit evidence on mammal distributions within many tropical PAs remains limited. This study addressed this gap by integrating systematic field surveys with species distribution modelling to map mammalian habitat suitability and richness in Inani National Park (INP), a coastal protected area in southeastern Bangladesh. Using transect surveys and camera trapping conducted in INP from November 2022 to November 2023, we recorded 23 mammal species, of which 19 were modelled by MaxEnt v3.4.4 using 1124 georeferenced occurrence records. Habitat suitability was predicted using environmental variables including land cover, vegetation productivity (NDVI), topography, and distance to water bodies. Model performance was strong across all species (AUC = 0.801–0.855), indicating robust predictive reliability. Results showed that mammal distributions were primarily driven by land cover and proximity to streams and khals, while topographic variables played a minor role. Species richness was highest in riparian corridors and shrub with scattered tree habitats, particularly in the southern and western parts of the park. Agricultural and settlement areas supported very low suitability and richness, indicating strong habitat filtering in human-modified landscapes. Overall, INP supports a spatially structured mammal community, with semi-natural vegetation and riparian systems acting as key biodiversity refuges. These results provide the first fine-scale, multi-species distribution maps for the park and a baseline for long-term monitoring. They highlight the need to maintain habitat heterogeneity and protect riparian corridors to sustain mammal diversity under increasing anthropogenic pressure.