An invasive alien species [IAS] is categorized as a plant or in some cases animal species that poses as a threat to the surrounding environment. It doesn’t necessarily have to be a non-native species. Examples can include certain weeds, water hyacinth, or critters and rodents.

Water garbage infiltrates the Perungulathur Lake water body in Chennai

Plant species specifically can be identified as invasive if they tend to grow and spread aggressively. These species are extremely damaging to the overall ecosystem and biodiversity. On the urban level, it’s interesting to know that such species can also set off a chain reaction affecting health and economic conditions of a country.

The Typha angustifolia is one such wetland species that poses as an invasive species.

India accounts for about 8% of the global biodiversity. Its diverse and rich set of habitats provide for its wide array of flora and fauna. About 40% of the Indian flora is alien, of which 25% are invasive alien species. Many such species are found interfering with green spaces and natural water bodies. One of the most common species found in wetlands is the water hyacinth. When the IAS affects water reservoirs and catchment areas, there is a threat to the water levels. There is also a possibility of waterways and irrigation systems getting choked up by such species

IMG_2776As for the infrastructure, clogged up waterways and irrigation systems in urban areas are only going to increase costs for municipalities. Floods are the next immediate set of consequences that towns and cities will face, with even a potential of water-borne diseases affecting citizens.

To combat the detrimental affects of invasive species, people resort to using pesticides. Releasing and breathing in these chemicals into the air only leads to indirect health problems, such as respiratory or allergic reactions.

Duck weedNot only is the overall ecosystem, and the health of citizens harmed, but these types of species deteriorate the soil, destroying our crops. Dependency on agricultural crops is then reduced. Without proper regulation and monitoring, such species can pose a threat to international horticultural trade and food security, challenging a country’s ability to produce safe and secure food. Trade and management policies will need to be re-looked at for each and every country if this were to happen.


Workers help de-weed the surrounding areas of Perungulathur Lake, Chennai.

This set of chain reactions will be unavoidable if the invasive species is not taken under control. There needs to be more intensive research on invasive species with a centrally accessible reservoir of data available to all. A proper detection, categorization and monitoring of these species is also necessary before it begins to spread. This needs to be done according to the level of threat and rate of spread in each bioclimatic zone. Best practices of IAS control from other countries need to be adapted and applied to the Indian context. Citizens can also get involved by gaining more awareness of the types of invasive species commonly found in their own backyards or vicinities. Local civic bodies need to mobilize volunteers to not only gain knowledge, but to involve them in the removal of invasive species.

Words: Arushi Dutt

Photos: Dr. Subramanean Janakiraman