Role of biological characteristics in the success of invasive alien plant species in tropical ecosystems of Thiruvananthapuram District, Kerala, India

Biological invasion is a leading threat to the abiotic and biotic equilibrium of natural landscapes and ecosystems through competition and habitat alteration in many countries, including India. The Invasive Alien Plant Species (IAPS)¹ have become an important biological and ecological component in Kerala, south-west tropical province of the Indian Union. These alien plant species were deliberately or accidentally introduced to the state from different biogeographical realms and are persisting. The characteristics of IAPS, as well as their preferences and advantages in invasion, have received little attention. This article provides a summary of the identifying characteristics of 69 IAPS reported from the study area, with an emphasis on botanical passport data, nativity, ecosystem preference, life form, sociability pattern, reproductive phenology, mode of dispersal, and period of introduction. Phytosociological research was conducted using a random sampling survey and line transect technique. The ecological performance of IAPS was statistically assessed according to seven concepts of invasion success. The findings show that 25 IAPS are considerably more aggressive as a result of their reproductive advantage and generally adhere to the concepts of invasion success for characteristics such as residence time, dispersal strategy, and ecosystem preference. Thus, reproductive characteristics appear to be a key determinant of aggressiveness in IAPS. The characteristic similarities of IAPS frequently result in niche overlap, and those with structural and functional differences will be more adaptable in ecosystems. This information describing the relevant characteristics serves as an essential tool for early detection and rapid response in the systematic management of biological invasion in the state of Kerala and specifically in the district of Thiruvananthapuram.