Determinants of abundance and habitat association of mammals in Barandabhar Corridor Forest, Chitwan, Nepal

Barandabhar Corridor Forest (BCF), the biologically functional corridor, is surrounded by the large human settlements that exploit the corridor where large mammals such as tigers, leopards and their prey such as ungulates, primates, and rhinoceros occur. This study aimed to evaluate major determinants that affect the distribution of large mammals in BCF, Chitwan, Nepal that connects the biologically significant Chitwan National Park with the Mahabharat range. The status and distribution of large mammals along the habitat and disturbance gradients were determined by using 29 line transects (mean length = 4.59 ± 0.38 km) that covered a linear distance of 133.13 km. The chital were the most abundant mammals (density per km² (D) = 8.9095 ± 1.4570 and encounter rate per km (ER) = 1.49) followed by rhesus monkey (D = 38.896 ± 16.013, ER = 0.28), wild boar (D = 14.814 ± 3.57, ER = 0.62), northern red muntjac (D = 9.6566 ± 2.9514, ER = 0.62) and sambar (D = 5.392 ± 2.319, ER = 0.38). Similarly, the sign encounter rate of tiger and leopard was 0.435 and 0.503 respectively. Habitat types, human disturbances, and coverage of invasive and alien plant species (IAPs) played a key role in the distribution of large mammals. The occurrence of mammals was low nearer to the settlements and roads and coverage of IAPs and more nearer to the water resources. However, degradation of foraging grounds such as grasslands by succession and invasion of alien plant species added more threats to the survival of large mammals. Therefore, such a situation can be improved through the scientific management of forests and grasslands.