Survey of Invasive Plants at Hin Nam No National Park, Khammoune Province, Laos

This paper represented the first survey of invasive plants at the Hin Nam No National Park, Khammoune province, Laos. We identified 33 invasive species among 78 alliance species. These invasive species cause an impact on the open habitats of the national park, mostly to the secondary evergreen scrubs, secondary semi-deciduous scrubs, secondary evergreen grasslands, secondary semi-deciduous grasslands, abandoned cultivated lands, residential areas, and sometimes to the regenerating evergreen forest or regenerating semi-deciduous forest. The worst impacting species that were first observed are Lantana (Lantana camara), Siam weed (Chromolaena odorata), Blackjack (Bidens pilosa). The medium-impacting species are Mysore thorn (Biancaea decapetala) and Billy goat weed (Ageratum conyzoides). This research provides foundational insights to the national park and local stakeholders about biological conservation and potential invasive plant controlling activities, such as focusing on controlling invasive plants in the borders of the national park. It is necessary to conduct a detailed study to identify exactly the impact of each species, including the impacted areas, the impacting pathway, and controlling methods. The research also recommends that Centre for Agriculture and Biosciences International (CABI) change the alliance status of 12 species to native and reconsider Blue porterweed (Stachytarpheta jamaicensis) as an alliance species.