Distribution and impact of invasive alien plant species in Bardia national park, western Nepal.
Invasive alien plant species (IAPS) are spreading into protected areas worldwide; however, knowledge of these invasions and their impacts in Nepal's protected areas is poor. Here, the spatial distribution pattern of IAPS in Bardia National Park (BNP), Nepal, was analysed using roadside surveys and grid sampling. The impacts of the most abundant IAPS, Lantana camara, on plant communities were analysed by comparing 60 pairs of non-invaded and invaded quadrats. Twelve IAPS, including two of the most prolific species globally, L. camara and Chromolaena odorata, were recorded from BNP. The Karnali floodplain in the south-western region of the park, a prime habitat of one-horned rhinoceros, was highly invaded by the IAPS. Tree canopy and distance to road, river and settlement were the major factors affecting IAPS occurrence. Lantana camara modified plant community structure and significantly reduced plant species richness and diversity; species richness of native plants was reduced to less than half in invaded plots. Plant invasions and impacts on native plant diversity have been increasing in BNP. We recommend management interventions involving immediate eradication of C. odorata and other species with single satellite populations and control measures for other widespread species such as L. camara and Ageratum houstonianum.