Impact of Invasive Alien Plant Species removal in the Forest Management: Findings from Terai and Mid-Hills of Nepal

Invasive Alien Plant Species (IAPS) are major threat to the earth’s plant biodiversity. With the rapid expansion of IAPS in Nepal, the techniques of using IAPS in form of charcoal have derived profound benefit to the forest condition. This study aims to analyse the effect of removal of IAPS on forest management in terms of plant diversity at regeneration level. In addition, the impact on the species richness, species evenness and stand density was also studied for three community forests representing different physiographic zones of Nepal. Each forest was divided into two blocks- treatment applied block and control block with size of 20 ha each. Treatment block represented the IAPS removed forest area while control block represented forest area with no intervention. The study was conducted using stratified random sampling. Forest inventory with nested circular plot of 500 m2, was performed in both blocks to figure out the changes in regeneration level. Shannon-Wiener diversity index was used to assess the change in diversities at regeneration level. Margalef index and Pielou’s evenness index were used to calculate species richness and evenness. According to Shannon-Weiner index, treatment block showed significantly higher plant diversity and a greater number of seedlings and saplings in comparison to control block. Similarly, the value of Margalef index and Pielou’s evenness index were greater in treatment applied block. Species density at regeneration level and growing stocks of trees were found higher in treatment applied block while species density at tree level in the control block. It is suggested that promotion of invasive species management through policy level/main actors of forest sector, capacity enhancement of local forest user and proper financing could be a strategy to secure dual benefit to forest and its user.