Legacy invasives cannot be allowed to run wild

The flowerhead gleamed softly, a wonder to behold. It looked like a bunch of flower-dots making up a bigger one. The leaves and blooms, when fondled, smelt of mint, and walking through a jumble of lantana bushes made you smell like a blossom: heady and lingering.

- NEHA SINHA

You could pick lantana colours in the way you pick "gems" candies-yellow and pink flowers, red, purple, golden yellow, marigold rust, and just pink. Initially, Lantana camara dotted hedges, snaked through abandoned lots, and grew upright in genteel, decorous rows. With the passing of time though, lantana bushes were no longer polite borders waiting on thresholds-they were the entire garden. In tiger reserves I visited later, lantana was the towering tree, the crouching bush, the foreground and the bokeh-it had essentially taken over entire swathes of land. A recent study (Mungi et al, 2020) estimates that 40% of Indian forest has been taken over by Lantana camera. Other observations note the takeover of invasive species leads to human-wildlife conflict, as animals like elephants venture out to fulfil nutritional needs.

Fortune favours the brave, they say, but in ecology there is something suspect about things that conquer an entire place. A single kind of bright flower dominating an understorey or a single kind of tree taking over the horizon does not signify survival of the fittest (or bravest). It usually denotes an invasive species a foreigner that outcompetes, outperforms and outmanoeuvres native species. Invasives lead to huge economic, ecosystem service and carbon sequestration losses.

This month, the lantana of childhood came to mind as I visited the Mudumalai tiger reserve in the Western Ghats. All around me stood trees with branches that speared out, like a crown of thorns. The crown was tipped with eye-meltingly yellow flowers. Like the lantana, these were ornamental and pleasing. But also like the lantana, the Senna spectabilis is invasive in India. Invasives present a kind of easy beauty that is beguiling, but this is also beauty with teeth and venom.