Although Sri Lanka is a small island, it has a wide variety of climatic, topographic and soil conditions that has resulted in a diverse array of aquatic and terrestrial habitats such as forests and grasslands, rivers, streams, mangroves, inland and coastal wetlands and coral reefs. Thus, Sri Lanka together with the Western Ghats of India, has been identified as one of the 34 Global Biodiversity Hotspots based on the number of endemic plants and vertebrates, their density and remaining vegetation relative to the original extent (Myers et al., 2000, Mittermeier et al, 2005). Birdlife International (BI) has also identified Sri Lanka as an endemic bird area (Myers et al., 2000). Furthermore, the island’s lowland rainforests, montane rainforests and south western rivers and streams are listed in the WWF’s Global 200 eco-regions as one of the most biologically distinct terrestrial, freshwater and marine eco-regions of the planet, and as such they are considered priorities for conservation (Myers et al., 2000).
The Global Invasive Species Database of the IUCN Invasive Species Specialists Group (ISSG) lists approximately 82 Invasive species or potentially invasive species as being present in Sri Lanka. These species have invaded human modified landscapes such as agriculture land, abandoned lands, irrigation systems, and home gardens. Some of the alien invasive species have also invaded natural ecosystems and therefore may have an impact on the rich biodiversity of the island. Most of these invasive species are either pets or ornamental plants used and distributed by man, which by accident have been released to the natural environment where they have become established. Some of the species however, have been introduced intentionally by various government line agencies or non governmental entities for specific purposes without realizing the invasive potential of these organisms.