Terrestrial Gastropod Fauna in Shivapuri Nagarjun National Park, Kathmandu

Abstract

A total of 1140 specimens representing 12 families, 20 genera and 39 species were reported from Nagarjun forest within altitudinal range 1300 to 1960 m above sea level. Family Ariophantidae was the most dominant family containing 10 species following Cyclophoridae (9), Heliocarionidae (6), Glessulidae (3), Diplommatinidae (3), Camaeinidae (2), Pyramidulidae (1), Clausiliidae (1), Subulinidae (1), Plectopylidae (1), Euconulidae (1) and Bradybaenidae (1). The numbers of specimens per 100 m² plot were ranges from 5 to 143 per whereas the species diversity in each plot ranges from 3 to 15 species. Shannon index of species diversity was calculated (H= 1.087) indicating high species diversity. Among the collected specimens Alycaeus burti was the most abundant (Pi = 0.147) and Alycaeus cf inflatus, Cyclophorus sp., Pyramidula humilis, Macrochlamys sp.C, and Bradybaena radicicola were the least abundant and found as singleton in Nagarjun forest (pi=0.00076). Species density was ranged from 0.18 to 28.03 per 100 m². The species diversity of terrestrial snails with altitude was negatively correlated (r = -0.10) but positively correlated with soil pH (r = 0.33).