Diversity of Alien Invasive Plants Species by Random Sampling Method and Impact on Local Flora at Kokrajhar, Assam

Studies recorded 43 invasive alien species (IAS) belonging to 19 different families from four different sub areas of Kokrajhar town. Frequency class was studied from selected area and results were compared with Raunkiaer’s frequency class to find homogeneity among the species. Random sampling methods shows highest density value with 1.2, 1.4, 2.3 and 2.4 in Ageratum conyzoides with least values as seen in Cleome gynandra (0.1), Crotalaria pallida, Oxalis corniculata (0.2) and Solanum viarum, Ipomea carnea, Eichhornia crassipes (0.3). Distributional pattern shows that majority of these invasive species are native of Tropical America. Thus, IAS recorded from the study area are found to be highly disturbed and it does not follow Raunkier’s frequency class. Ethnomedicinal usage for the recorded species shows that most of them are used externally for cuts, burns and wounds with some of them also being consumed internally by the ethnic tribes residing in Kokrajhar town.