Diversity and habitat utilization of terrestrial gastropods in Lava, West Bengal, India, with particular emphasis on Deroceras laeve distribution

ABSTRACT: The eastern Himalayas comprise an extensive malacofauna diversity, but most of the earlier studies are based on taxonomy and little consideration was given to their ecology. In this context, the diversity, habitat utilization, and microhabitat preference of terrestrial gastropods occurring in Lava, India, were assessed in this study. As an extension, the season-wise availability of the non-native slug, Deroceras laeve, was evaluated along with the estimation of suitable habitats of D. laeve in the Darjeeling Himalayas under the current and future climates using species distribution modeling. During the survey, 5033 individuals belonging to 13 gastropod species were encountered, and Cryptaustenia heteroconcha was the most abundant gastropod, followed by Macrochlamys sp. and D. laeve. Macrochlamys sp. and Kaliella sp. were the most generalist and specialized species regarding microhabitat utilization. D. laeve and C. heteroconcha were mostly found on ornamental plants and crops, respectively. The abundance of D. laeve and its eggs was greater during the monsoon season than in the other seasons. The results of species distribution modeling identified discrete regions of the Darjeeling Himalayas with high and moderate suitability for D. laeve occurrence, which may reduce with climate change. The present observations may help to frame conservation (of native gastropods) and management (of pestiferous gastropods) strategies through the identification of microhabitat preferences and suitable habitats.