Mon. Apr 22nd, 2024


Invasive plant species have invaded 22% of the natural habitats and have potential to reach up to 66% of green areas in India, a new study released on Thursday said, basing its findings on the study of 3,58,000 square km of tiger habitats across 20 states.

Lantana camara was found to be most invasive of the 11 invasive plant species studied by the scientists. (HT)
Lantana camara was found to be most invasive of the 11 invasive plant species studied by the scientists. (HT)

Biological invasions threaten biodiversity and human well being, with developing tropical countries such as India being more vulnerable, said the study done by two Wildlife Institute of India (WII) scientists, Ninad Avinash Mungi and Omar Qureshi and the institute’s former dean, Y V Jhala.

The five-year long study published in the peer reviewed Journal of Applied Ecology on Thursday studied 1.58 lakh plots covering 358,550 sq km and focussed on spotting 11 most prevalent invasive species in the country.

The sampling covered 31% of savannas, 51% of dry deciduous forests, 40% of moist deciduous forests, 29% of semi-evergreen forests, 44% of evergreen forests and 33% of moist grassland savannas.

“High-concern plant invasions were recorded in 22% natural areas and modelled to potentially threaten 66% natural areas. These estimates were statistically robust as suggested by accuracy indicators,” the study said.

Savannas had highest suitability for invasions (87%) followed by moist grasslands and dry deciduous forests (~72% each), while evergreen forests were relatively least suitable (42%), the study said. Lantana camara was found to be most invasive of the 11 invasive plant species studied covering around 50% of the natural habitat found invaded. Mikania micrantha had relatively least expanse and was predominantly found in moist grasslands and forests, the study said.

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It also found that anthropogenic disturbance in form of livestock grazing and climate change-induced agro-climate conditions facilitated spread of invasive species. Invasive species have the potential to take over native species and impacts natural forage and habitat quality, the study said.

“These prevalent human modifications likely explain the pervasive invasions across India. The influence of other environmental drivers could be broadly segregated in dry and wet systems. Proximity to water was found to facilitate invasive plants of dry systems (savannas, dry deciduous forests, etc.), whereas proximity to fire facilitated invasive plants of wet systems (semi-evergreen and evergreen forests),” the study said.

Jhala said that it was for the first time that the magnitude of the problem through country-wide surveys has been documented. “The study identifies high invasive potential zones and could help the government in putting policies in place to deal with them as they have potential to destroy the ecological systems,” Jhala said.

The study found high potential of invasive species in central India and Western Ghats, where almost half of the India’s 3,682 tigers live, as per the 2022 tiger estimation. The environment ministry has already identified the problem of invasive species in tiger habitats. The ministry has implemented national-scale invasive plant monitoring by integrating it with the umbrella project on tiger assessment.

Using the surveys conducted for tiger estimation in 2018, the WII scientists found that two-thirds of India’s natural areas are under multiple plant invasions, owing to the legacy of anthropogenic modifications. The study said “one-time management” of invasive species in Indian forest will need US $ 13.5 billion, which would be a difficult task and therefore, recommended “restoration priority” to be assigned to least invaded areas to maximise biodiversity returns.


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