Determinants of Herpetofaunal Diversity in a Threatened Wetland Ecosystem: A Case Study of the Ramaroshan Wetland Complex, Western Nepal

Abstract

Wetlands are among the highly threatened ecosystems due to anthropogenic activities. The Ramaroshan Wetland Complex (RWC) of Achham District, Nepal is one of the high-altitude wetlands facing human induced degradation and loss. Herpetofauna are key bio-indicators of environmental health and habitat quality and are useful to assess habitat conditions of such threatened ecosystems. This study quantified the land use and land cover (LULC) change in the RWC and documented the diversity and distribution pattern of herpetofauna. The LULC in the area (13.94 Km2) was analyzed for 1989, 2000, 2010 and 2021 by supervised classification of remote sensing images. Surveys were conducted along 25 transects, each of 200 m in length and environmental variables were recorded for every observation of herpetofauna. The LULC analysis revealed an overall loss of 16% of the total water body between 1989 (0.25 Km2) and 2021 (0.21 Km2). Eleven species of herpetofauna (five amphibians and six reptiles) within five families and two orders (i.e., Anura and Squamata), were recorded with low diversity (H’ = 1.88312) and evenness (E = 0.3642) indices. The herpetofauna had a hump-shaped distribution along the elevation gradient with the highest richness and abundance at 2300 m asl. Amphibian abundance decreased with increasing distance to nearest water sources, whereas reptile abundance increased. Amphibians were more abundant in agricultural field and marsh land, whereas reptile abundance was higher around human settlements. Results indicate that the wetland area in the RWC is declining at an alarming rate and, in turn, might account for the low diversity and abundance of the herpetofauna.

Wetland biodiversity of Ramaroshan Lake complex: a need for conservation

“…Like other wetlands in Nepal, the lake complex is also affected by land encroachment. In 30 years, the wetland area of the complex has shrunk by 16% due to land use and land cover changes (Paudel et al 2022).…”

Addressing the impacts of climate change on agricultural adaptation strategies: a case study in Nepal

“…Over 61% of the population conducts subsistence agriculture and small-scale livestock husbandry in the middle mountain regions. According to Paudel et al (2022), household farmlands in Mangalsen Municipality are primarily located in the challenging wetland ecosystem. The soil texture is silty clay with an average organic soil carbon content of 1.8%.…”

Effect of water physicochemistry on amphibian abundance in Sub-tropical Kupinde Lake of the Nepal Himalaya

“…They play important roles in the trophic levels of the ecosystems (Mifsud 2014;Thakuri and Pokhrel 2017;Ali et al 2018). Amphibians are excellent indicators of wetland ecosystem health because they rely heavily on water (Hecnar 2004;Amankwaa et al 2020;Riyanto and Rahmadi 2021;Paudel et al 2023) and play a key role in forecasting environmental quality in their habitats (Mifsud 2014;Amarasinghe et al 2021). They provide various ecosystem services, such as religious and cultural services, food, and medicine (Shah and Tiwari 2004;Paulding and Randhir 2021).…”

“…Wetlands of the Himalayan region are threatened due to anthropogenic pressure and climate change (Paudel et al 2023). Lakes in the mid-hill region of the Nepal Himalayas are important ecosystems providing multifaceted services.…”