The flower head shone softly, a wonder to see. It looked like a small flower within a flower, or perhaps a bunch of flower dots that together formed a larger one. As you caressed the leaves and flowers you smelled of mint, and as you walked through a tangle of lantana bushes you smelled of blossom: intoxicating and lingering.
You can choose Lantana colors the way you pick “gem” candies: yellow and pink flowers, red, purple, golden yellow, marigold rust and plain pink. Initial, Lantana camera dotted hedges, wound through abandoned plots and grew upright in stately, graceful rows. However, with the passage of time, lantana bushes were no longer polite borders waiting on thresholds – they formed the entire garden. In the tiger reserves I visited later, Lantana was the towering tree, the crouching bush, the foreground and the bokeh; he had actually confiscated entire tracts of land. A recent study (Mungi et al, 2020) estimates that 40% of Indian forests have been taken over by Lantana camera. Other observations indicate that the takeover of invasive species leads to conflict between humans and nature, as animals such as elephants venture out to meet their nutritional needs.
Fortune favors the brave, they say, but in ecology there is something fishy about things taking over an entire place. A single species of bright flower dominating an undergrowth or a single species of tree taking over the horizon does not mean survival of the strongest (or the bravest). It usually indicates an invasive species: a foreigner that outcompetes, outperforms, and outmaneuvers native species. Invasives cause enormous losses in terms of the economy, ecosystem services and carbon sequestration.
This month, the lantana of childhood came to mind when I visited the Mudumalai Tiger Reserve in the Western Ghats. All around me were trees with branches sticking out of them, like a crown of thorns. The crown was tipped with eye-melting yellow flowers. Like the lantana, these were decorative and pleasant. But also like the lantana, the Senna spectabilis is invasive in India. Invasives present a kind of easy beauty that is seductive, but this is also beauty with teeth and venom.
But for the first time we have a law that changes the state of affairs. An amendment to the Wild Life (Protection) Act (also known as WLPA) introduced last year provides guidance on how to tackle invasive species. If you have visited island countries like Great Britain and Australia, you already know that you are not allowed to transport foreign fruits or seeds to these countries because they are unknown exotics or invasive species. India also has islands, which are hyper-sensitive to invasive species; so is the mainland. But despite major economic and environmental threats, we still lack a national action plan to identify, eliminate and monitor invasive species. Shockingly, despite changes in the law, invasive fish and plant species are easy to buy. Nurseries sell Lantana camera in as many colors as you want – all gemstones in candy colors. You can sow a field of golden lantanas, bordered by pink and yellow, without feeling guilty about, say, owning an anachronism like a piece of ivory.
Water hyacinth covers a wetland in Haryana.
The WLPA is a start, but there is an urgent need to get started now. First, we need to establish a complete list of invasive species in land and water. Invasives are equal opportunity offenders who also end up in the waters. The water hyacinth, another striking, easy-to-grow invasive plant, covers wetlands with its emerald mat and purple blossoms; suffocating the wetland and causing hypoxia, or the reduction of oxygen.
Second, we must identify strategies to destroy invasive species. Some persistent invasive species need to be burned, completely uprooted and further controlled. Third, we must not act at cross purposes: all stakeholders must be made aware of the dangers of invasive species.
Then, innovative livelihood practices should be promoted to control invasive resources, such as reed-like furniture made from water hyacinth or lantana. And finally, we face a huge communication and outreach challenge: we must start educating local welfare organizations, farmers, gardeners, governments and more from the very beginning.
“We have taken an important first step in recognizing the problem of invasive species,” said Abi Vanak, senior fellow at the Ashoka Trust for Research in Ecology and the Environment. He adds: “From a policy perspective, this needs to be integrated across the board across all ministries and departments that handle biological material of any kind. This requires multi-sectoral coordination between all relevant ministries to ensure that minimum standards for inspection and quarantine are established, with the National Biodiversity Authority (NBA) being a coordinating body, as prescribed by the Biological Diversity Act. Moreover, we must ensure that ministries do not act in opposition to each other. For example, the Indian Council of Medical Research has issued guidelines for the introduction of the highly invasive Gambusia fish to control mosquitoes, without considering the fact that the NBA has classified them as an invasive species.”
Another complication is that invasive species can become perversely integrated into the way of life, even as they harm the overall ecosystem. In the famous Delhi Ridge forest, you can easily spot a thorny, feathery tree with a twisted trunk. This is more of a gray than a tree, and this gray covers miles of forest. This is the Vilayati kikar or Prosopis juliflora, the main enemy of ecosystems. This South American tree renders the land beneath it virtually unable to support other trees, in classic invasive fashion. Still, pastoralists use the tree in some landscapes. This means that there may be social barriers to clearing invasive species, implying that they must be destroyed before they can become established.
I have seen birds and animals sitting on it Vilayati kikar, but very few feed on the thorny branches. In the Delhi Ridge I watched a male gray hornbill gently feeding a female while perched on the ground Vilayati kikar. The birds were framed in a luminous, uniform green shade of other foreign birds kikars. It was a perfect, beautiful scene. But optics isn’t everything. As the Prosopis was actually a Goolar fig tree (which grows bunches of figs), a sprawling Banyan, or even a hardy Peepal, the birds would feed each other figs from the same tree. They would be joined by monkeys, barbets and bats, and probably argue with some of them. In fact, they would be the center of a thriving native ecosystem. This is what reclaiming hundreds of kilometers covered by invasive lantana, juliflora or senna will mean: native forests actually behave like forests.
Yesterday, state governments were willfully (and cheerfully) planting Prosopis julifora, looking for a quick green solution. Today, a huge, invasive apex predator from the Amazon – the Arapaima fish – swims in the waters of Kerala. And tomorrow will be a green desert if we don’t pay attention to our invasive invasions.
Neha Sinha is a conservation biologist and author of Wild and quirky: stories about 15 iconic Indian species. Opinions expressed are personal.