Habitat Selection of the Smooth-Coated Otter (Lutrogale perspicillata) in Shuklaphanta National Park, Nepal

Abstract

Smooth-coated otters are top predators, semi-aquatic carnivores, and keystone species in the aquatic ecosystem, serving as important biological indicators of wetland health. The species, once widespread across the Terai, is now limited to buffer zones and protected areas. This research investigated the habitat selection of smooth-coated otters within the Shuklaphanta wetland landscape, an ecologically significant area in the Western Terai lowland of Nepal. The field survey was conducted using line transects with a length of 200 m in a 600 m long section along the bank of the Chaudhar River and the wetlands. A total of 71 line transects were sampled, 53 in the Chaudhar River and 18 in the wetlands. Of these, 15 transects in the Chaudhar River and 18 in the wetlands revealed signs of the presence of smooth-coated otters. Five habitat variables (canopy cover, water channel width, river bank slope, bank substrate, and human disturbance) play important roles in the presence of otters. The relationship between otter presence and habitat variables was determined using binomial logistic regression. The probability of smooth-coated otter presence increased with an increase in canopy cover, a higher proportion of sand and mud, and wider water channels. In contrast, otter presence decreased with an increase in the Human Disturbance Index and bank slope. However, average depth and water current appeared to have no significant effect on the presence of smooth-coated otters. Regular monitoring of smooth-coated otter habitats and vegetation, along with reducing anthropogenic activities, is urgently needed to conserve the smooth-coated otter and its habitat in the western lowlands of Nepal.