Invasive Alien Species of Asteraceae and their Economic Importance in Nilgiri District, Tamil Nadu, India

Nilgiris is one of the major biological communities affected by alien and invasive species in the plant kingdom. Nilgiris has a rich biodiversity of invaded by alien species. The present study deals with the Asteraceae member of invasive plants species in Nilgiri District. The Nilgiris hills were colonized by the British who introduced a number of Mediterranean and European plants. Most of the invasive exotic plants belong to Asteraceae family. A total of 103 invasive species of Asteraceae plants were recorded, belonging to 68 genera during the present study. 25 percentages of the invasive species are considered to be of medicinal value; namely, Galinsoga parviflora, Silybum marianum, Erigeron canadensis, Taraxacum officinale. But some of the species like Lagascea mollis, Senecio vulgaris, Solidago canadensis and Parthenium hysterophorus are considered to have high allelopathic properties as well as having harmful effects on nature and plant population. Exotic species are normally introduced in a habitat by humans rarely in a planned manner but or by accident. These aliens in due course, by proliferation, get naturalized. Even though they get acclimatized and naturalized with the habitat they have to be considered as invasive. In addition a prolific alien has every chance of creating it’s own micro climate in the habitat, alienating the endemic species of the habitat. To stop proliferation of such weeds, timely monitoring and removal must be done. Best method of stopping further proliferation is by removing en masse the flowering tops of the weeds by mechanical or any other practicable means.