Species Diversity and Ilabitat Preference of Herpetofauna in Lumbini Region, Nepal

Abstract

The herpetofauna (amphibians and reptiles) are diverse and poikilothermic vertebrates that serve as excellent bio-indicators of stressed ecosystems. There is little information on the taxonomy, diversity, abundance, and distribution of herpetofauna in the Lumbini region. The aim of this study is to explore the species diversity and habitat preferences of herpetofauna in this region. The study was conducted from March 2016 to July 2020, in six districts. A total of 36 stations were chosen in these districts. From each station, sampling was done in five different habitats, namely agricultural fields, forests, riparian habitats, wetlands, and human habitats. Five transects, each of 200 m, were fixed in each habitat. In each transect, four quadrats of 20 m x 20 m were used for searching specimens using raking and digging methods. Additionally, pitfall, visual encounters, and opportunistic surveys were used to maximize the collections. The morphometric measurements and the use of specified keys, all species were classified at the species level. The abundance, species richness, diversity, and habitat preference were analyzed in Microsoft Excel, PAST (4.11 version), and R (version 3.6). Arc GIS was used to prepare a distribution map of herpetofauna. A total of 4,589 and 2,629 individuals of amphibians and reptiles were observed, respectively. There were 58 species of herpetofauna that included 17 species of amphibians and 41 species of reptiles. Amphibians included 12 genera and 6 families: Bufonidae, Megophryidae, Microhylidae, Ranidae, Rhacophoridae, and Ichthyophidae. Reptiles included 30 genera and 12 families: Crocodylidae, Trionychidae, Bataguridae, Agamidae, Gekkonidae, Varanidae, Scincidae, Typhlopidae, Boidae, Colubridae, Elapidae, and Viperidae. Euphlyctis cyanophlyctis, Minervarya nepalensis, Minervarya teraienesis, Duttaphrynus melanostictus, Hoplobatrachus tigerinus, and Microhyla ornate were highly observed individuals among amphibians, whereas Ichthyophis sikkimensis, Uperodon taprobanicus, Sphaerotheca breviceps, and Nanorana liebigii were least observed individuals among amphibians. The habitat-wise species richness of amphibians was 14, seven, 11, 16, and seven in agricultural fields, forests, human habitats, riparian areas, and wetland areas, respectively. D. melanostictus, D. stomaticus, E. cyanophlyctis, Hoplobatrachus, Minervarya species, and M. ornata were common species found in every study site. I. sikkimensis was a new distributional record among amphibians in the Lumbini region. Polypedates leucomystax was distributed in both the Terai and mountainous regions. Simpson's Index, Shannon index (H), and Pilou’s evenness (J) of amphibians were found to be the highest in riparian areas, whereas it was found the lowest in wetlands. Among reptiles, Calotes versicolor, Ptyas mucosa, and Xenochrophis piscator were the most observed species, whereas Crocodylus platuris was the only species observed throughout the survey period. C. versicolor is a widely distributed species, Laudakia tuberculata was found in the mountains, and turtles were found in the Terai region. Snakes were prevalent in human habitats and forests, while geckos dominated the lowlands, and skinks inhabited the forests only. C. palustris is a new distributional record of this region. The Simpson index, Shannon indices (H'), and Pilou’s evenness were recorded high in forests while low in wetlands. Among the 27 identified snakes, eight were venomous, and 19 were non-venomous. Three species of Boiga among non-venomous were semi-venomous. The present study shows that herpetofauna utilized more than two habitats and are also species-specific. Amphibians preferred riparian areas, while reptiles preferred the forest. These habitats were protected for the conservation of amphibians and reptiles. This area has a taxonomically rich herpetofauna, but C. palustris, Varanus flavescens, Python species, Oligodon erythrogaster, Trachischium tenuiceps, and Ophiophagus hannah were the least observed species and also marked as threatened species in the IUCN Red List of threatened species. The protection of these species is essential.