By Nobin Raja & Priya Ranganathan

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A beautiful flowering weed, Lantana camara adds colour to the green landscapes of India’s forests. It grows rampantly in people’s gardens and pops up in the least-expected places. Many rural communities use it to craft sturdy furniture and other artisan crafts to sell in markets. But the spread of Lantana across India marks an eerie, otherworldly presence – aliens in India.

Lantana camara, an invasive plant in southern India (Image: Priya Ranganathan)

Alien species are those that have colonized parts of the world where they are non-native. Take Lantana for instance; it hails from Central and South America but was imported into India in 1809 as an ornamental shrub. Now a menace in forests across southern India, Lantana suppresses the growth of native plants that herbivores such as gaur, deer, and elephants usually eat. When this happens, wild herbivores often seek out easier food sources in nearby agricultural fields.

Many of the plants we grow, fruits and vegetables we eat, and animals we see are not native to India. As people travel more often across the globe, the chances of animals and plants migrating thousands of kilometres away to foreign soil increase as well. While most of these alien invasive species are relatively harmless, certain species can spell trouble for local ecosystems. Let’s take a look at a few examples:

Water hyacinth (Illustration by Manini Bansal)

Towards the end of the 18th century, the British gifted a beautiful aquatic plant – the water hyacinth – to India. This plant, with its bright purple bloom and elegant green leaves, brightened up Indian lakes, ponds, and rivers. However, the water hyacinth is native to the Amazon River of Brazil, and its arrival in India soon created poor conditions in Indian water bodies. The plants grew out of control, spreading across the water surface in dense carpets and reducing oxygen levels and light in the water. This directly affected aquatic life, be it fish, insects, or plants, and the livelihoods of the people who depended on those lakes and rivers. The water hyacinth also blocks rivers and canals, causing flooding during the monsoons, and chokes wetlands. But it does have a good side – this plant is very good at surviving on polluted water and reduces the level of pollution considerably. It can even clean up wastewater polluted with heavy metals and oil, according to scientific research! Not all aliens are wholly bad, I suppose!

Gambusia (Illustration by Manini Bansal)

Another tiny invader is the mosquitofish (Gambusia affinis), introduced to India from the United States to control mosquito populations. We all know that malaria and dengue are two common mosquito-borne diseases in India. Well, this tiny fish eats mosquito larvae, making it a special guest in our country. However, due to the warm climate and plentiful food, the mosquitofish spread quickly through rivers and between lakes, using flooding waters from the monsoon as a mode of transport. Soon, it was found across the country and even in the creeks of the Andaman and Nicobar Islands far off the coast of India! Despite being incredibly useful in mosquito control, the mosquitofish also competes with native fishes, consuming food much faster than native species and reproducing quickly. This reduces the ability of local species to survive, reducing the fish diversity in India.

Invasive species have both good and bad effects on the countries that they invade, but they are undoubtedly here to stay! Scientists and the government are now looking into ways of controlling their spread and using them for other purposes to try and save the livelihoods of the people who have suffered because of these aliens. But for now, we can excitedly tell our friends and family that there are aliens living amongst us and they are not going away without a fight.

About the Authors:

Nobin Raja works on conservation genetics, focusing on invasive species, and is currently pursuing a Ph.D. with ATREE, Bangalore. A student of genomics, he adores physics, especially anything to do with Feynman.

Priya Ranganathan is a wetland ecologist and geologist by training who works in the wild Western Ghats. When she isn’t out wading through swamp forests, she can be found scribbling away in her notebook or practicing Bharatanatyam. Check out her website at ‘On Life and Wildlife.’

About the Artist:

Manini Bansal is a visual communication designer who loves her time in nature. She enjoys looking for marine creatures in tidepools and hidden insects during her treks.