DEEP INVASION

Invasive ornamental shrub lantana is altering traits, fast spreading across India's forests

- SHUCHITA JHA

IT IS not easy for any species to outperform the natives that have already adapted to local surroundings. But lantana (Lantana camara), an ornamental shrub, has mastered the art of invasion and is further honing its skills.

Since lantana was first introduced to the country from Latin America in the early 1800s, the weed has spread all over the country. The "India State of Forest Report 2021", released in January 2022, states that more than 9,793 sq km-an area larger than Sikkim-is under lantana. In fact, the spread of lantana is only marginally less than the combined spread of 28 other invasive species. At places, it has also taken over the biodiversity, choking out the native flora. For instance, in 1997, some 96 per cent of the Western Ghat reserve was under native flora, while 4 per cent was under lantana. By 2018, the area under native flora had shrunk to 53 per cent, while lantana occupied 47 per cent of the reserve, as per Bengaluru-based non-profit Ashoka Trust for Research in Ecology and the Environment.

Now, researchers say that the invasive weed has started to infiltrate the dense forests in the country. Almost 44 per cent of India's forests might have already been invaded by lantana, suggests a 2020 study published in the journal Global Ecology and Conservation (see 'Major attack'). For the study, "Expanding niche and degrading forests: Key to the successful global invasion of Lantana camara (sensu lato)", researchers Ninad Avinash Mungi, Qamar Qureshi and Yadvendradev Jhala of the Wildlife Institute of India, Dehradun, surveyed 207,100 sq km of forests in 18 states and found the weed across 86,806 sq km.

The study, based on spatial data, says that lantana has expanded its climatic niche worldwide, with more than 11 million sq km suitable for its invasion.