The unwanted guests

Parthenium and Lantana plants have encroached many parts of Mudumalai Tiger reserve,a herd of Spotted deer looking for food in the reserve. Photo: M. Sathyamoorthy   | Photo Credit: M_Sathyamoorthy;M_Sathyamoorthy -

It’s a joy to find a new plant sprouting in your garden, unless it is an invasive species. Invasive species are like unwanted guests. They are species not native to a specific region, but can grow exponentially and encroach into the space of the native species.

These introduced species may be plants, fungus and animals that invade and slowly dominate the region, causing damage to the habitat, environment and ecology. That does not mean all introduced species are invasive. On the contrary, even a native species could become invasive, if they could colonise the natural areas.

Some invasive species of plants in India include Senna spectabilis (calceolaria shower), Lantana, Eupatorium and Parthenium.


Invasive species are characterised by rapid reproduction, high dispersal ability, ability to adapt to new environment and ability to survive eating/consuming wide variety of food. They can outperform the native species and take away their nutrition, light, space and food.

Favourable environment

An invasive species can capitalise on the rich availability of resources in the new environment, which the native species had not utilised.

Invasive species often exploit disturbances to an ecosystem such a wildfire to colonize an area. Wildlife can sterilise soil and add nutrients to it. The native species lose their hold. Making the most out of the situation, invasive species, especially those that can regenerate from their roots start to grow here and multiply.

What harm can they do?

Invasive species can disrupt the balance in an ecosystem. When there is a land clearing, for instance, invasive species colonise the area, leaving no room for local ecosystem.

Weeds reduce yield in agriculture. They can accumulate nutrients from the subsoil and deposit them on the topsoil. They also attract insects and pests. The new plants also reduce food for grazing cattle and honeybees who visit the region for nectar. Some can spread diseases to the local plants. Invasive species can impact outdoor recreation, such as fishing and hunting.

Can't tackle them? Let's eat them

Invasivorism is a movement that supports the idea of eating invasive species in a way to keep a check on them. Lionfish, which is taking over the waters of Caribbean and Mexico, has found its way into menus in Miami. Purslane, Japanese Knotweed, Dandelion, Kudzu (in the picture) and Curly Dock are some of the plant species that can be eaten.

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Printable version | Sep 24, 2021 11:37:26 AM |

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