Lantana I.A.S. (Invasive Alien Species)

by Ranjini Murali

How can a flower look so pretty, yet…

 

Have you seen this plant before? Where have you seen it? Around your house? In the forest? I see that plant everywhere. When I was growing up, I used to eat the berries of that plant. I loved it. It was only later I was told that plant was called Lantana and it was evil.

Lantana is not originally from India. It is originally from the American tropics but it was brought to India in the 19{+t}{+h} century as an ornamental garden plant.

But this plant escaped from the gardens and started spreading around the cities and from there it entered the forests. In this way, Lantana became an invasive plant in India.

So why are invasive plants like Lantana evil, you might ask? They spread extremely fast and cover large areas. It is estimated that Lantana has invaded more than 1,30,000 km{+2} of area in India. This is about the size of Tamil Nadu! Can you imagine an area as big as Tamil Nadu covered with only one plant?

Scientists think there are many reasons Lantana spread so fast. For one, it is extremely adaptable and can grow in tropical, subtropical, and temperate climates. It produces a large number of seeds that are dispersed by birds and other animals that eat the fruits of Lantana.

Even water helps disperse the seeds of Lantana. It can use the soil nutrients and water much better than the native plants. It can prevent the young plants of the native vegetation from growing by releasing chemicals into the environment that are toxic to other plants. Finally, once it has established itself it grows as clumps and prevents anything else from growing.

What’s the big deal, you might ask. In fact invasive species are one of the biggest threats to conservation in the world today.

Instead of there being multiple kinds and types of trees and plants that a variety of animals can use, now the forest has mainly Lantana. As the trees in the forest disappear, the animals depending on them will also slowly start to disappear. Lantana is also a dense shrub with thorns and this is capable of restricting animal movement.

If it’s so bad, why is it not evil in the country it originally comes from, you might ask? When species evolve, several species evolve together and they place natural checks on each other. In this way, one species doesn’t take over the landscape. With invasive species, they are taken out of their natural environments and placed in a new environment.

Here, the natural checks – the animals and plants they evolved with, that control them – are removed. This along with favourable environmental conditions can cause certain species to spread in new landscapes. This is one explanation for Lantana spreading in India.

What can we do about this? Many methods have been used to try to control the spread of Lantana right from individually plucking the plants out of the soil to burning them.

However, none of these strategies have worked very well. Scientists have been studying this plant and its spread so that we are able to better understand this plant and the change it brings. Until they come up with a solution, Lantana remains a formidable enemy.

This article appeared in the Hindu in School on 7 August 2013.

Photo: A butterfly sucking nectar from lantana flowers Credit: Ch. Vijaya Bhaskar