Invasive Alien Flora

Invasive Alien Plant Species in Flora of Pantnagar

Flora of an area is always made up of two types of plants- ‘natives’ or indigenous plants and ‘aliens’ also known as exotic plants or introduced plants or non-native plants. Invasive plants are a subset of naturalized alien plants that produce reproductive offspring, often in very large numbers, at considerable distances from the parent plants, and thus have the potential to spread over a large area. These include Transformers (plants that change the character, condition, form or nature of ecosystems over a substantial area) and Weeds (plants that are undesirable at a particular place) as defined by Pysek et al. (2004).

None of the flora of the world is exclusively composed of native elements and the percentage of blended alien elements with it simply indicates the ‘biological pollution’, which may have catastrophic economic and ecological ramifications (McNeely 2001, Carey 2002, Pimental et al. 2005). Therefore, the compilation of regional flora, keeping in mind the alien and native elements, is of immediate relevance (Pysek et al. 2004), not only for simply analyzing the floristic diversity but also for assessing the impact of human activities (intentional or unintentional) in deterioration of the native flora. Indian flora also includes a large number of invasive alien species of angiosperms. Botanical Survey of India has listed 173 species of invasive alien angiosperms with their families, habits and source of origin (nativity).

In the Pantnagar area, the landscape is completely devoid of natural Tarai forests and the land is mainly used for agricultural activities, monoculture plantations, building construction, roads, playgrounds, parks, lawns etc. Such an environment, continuously disturbed by different anthropogenic activities, is congenial for invasion by Invasive Alien Species (IAS) and their presence in the area has been sporadically reported earlier (Gaur & Rawat 2013, Joshi & Rawat 2011, Nisha et al. 2015, Rastogi et al. 2015). Thus this area provides a classic environment to study the impact of changed land use on floristic composition.

The Global Invasive Species Database (GISD) developed by the Invasive Species Specialist Group (ISSG) of IUCN has published a list of "One Hundred of the World's Worst Invasive Alien Species". A perusal of the Invasive Alien Species list of Pantnagar proves the presence of Arundo donax L. (Poaceae), Hiptage benghalensis (L.) Kurz (Malpighiaceae), Imperata cylindrica (L.) Raeusch. (Poaceae), Leucaena leucocephala (Lam.) de Wit (Fabaceae), and Lantana camara L. (Verbenaceae) in this area are among the listed 100 worst invasive alien species in GISD.

Preliminary information on the flora of Pantnagar indicates the presence of the following Invasive Alien Species (IAS) in this area. Invasion is a continuous process and as and when any other species is noticed, it will be added here. Larger images of these species can be seen by clicking on the name of the species.