Invasive alien plant species and their effect on the occurrence of mammal species in Shuklaphanta National Park, Nepal

Abstract

Abstract The introduction and colonization of invasive alien plant species (IAPS) is one of the major threats to the conservation of native flora and fauna. These species are noticed within several protected areas, including lowlands of Nepal, causing adverse effects on both the species and ecosystem services. The effects of IAPS on threatened mammalian species, especially with regards to their occurrences, remains little known. We identified the effects of IAPS on the occurrence of threatened mammalian species at Shuklaphanta National Park (ShNP), Nepal from 11 November 2020 to 11 June 2021. We categorized ShNP into IAPS invaded and non-invaded habitat. We recorded the occurrence of threatened mammal species from 210 plots of 10 m X 10 m along the line transect. Altogether, we recorded 11 invasive alien plant species. Among them blue billygoat weed (Ageratum houstonianum) had the highest abundance in the study area. We recorded 25 mammal species in the study area, whereas 11 were threatened. Among the threatened species, 10 were found in the habitats invaded by IAPS, while all 11 were identified in non-invaded habitats. We found the higher occurrence of threatened mammal species closer to the forest where the abundance of IAPS was observed to decrease. In addition, we observed the occurrence of mammal species increased as the distance from the water source, road, human settlement, and agricultural land increased, indicating that the abundance of IAPS also decreased with increasing distance to water source, road, human settlement and agricultural land. Our findings suggest that the threatened mammal species tend to utilize the non-invaded habitat of IAPS over the invaded habitats. For developing a more suitable habitat for threatened mammal species, we recommend the removal or control of IAPS from ShNP.