India is home to a rich diversity of flora and fauna, but it is also facing a serious threat from invasive plant species that have spread across its natural areas.
A new study, based on the world's largest wildlife survey, reveals that 66% of India's natural systems are threatened by invasive plant species, including Lantana camara, Prosopis juliflora, and Chromolaena odorata.
The impact of invasive plants on India's ecosystems
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Invasive plant species are plants that are introduced to a new region, either intentionally or accidentally, and become dominant over the native vegetation.
They can have negative impacts on the ecosystem by competing with native plants for resources, altering soil properties, changing fire regimes, reducing biodiversity, and affecting wildlife habitat and food availability.
According to the study, published in the Journal of Applied Ecology, invasive plant species have invaded 22% of the natural habitats and have the potential to reach up to 66% of green areas in India.
The study was based on the data collected from 158,000 plots of land across 358,000 square kilometers of tiger habitats in 20 Indian states.
The researchers used a mobile app to record the presence and abundance of 11 invasive plant species along with other habitat parameters as part of India's national assessment of tiger populations.
The study found that Lantana camara was the 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 also revealed that invasive plant species were more prevalent in dry deciduous forests, scrublands, and grasslands than in moist deciduous forests and evergreen forests.
The researchers said that invasive plant species pose a serious threat to India's natural habitats and wildlife, especially endangered species like tigers and elephants.
"Plant invasions end up altering these habitats and revealing intricate ecological changes," said Professor Qamar Qureshi from the Wildlife Institute of India, one of the authors of the study.
He added that invasive plants can reduce the availability and quality of food and cover for wildlife, affect their movement and dispersal patterns, and increase human-wildlife conflicts.
The need for strategic management of invasive plants in India
The study also proposed a model to identify priority restoration sites, where invasions are in their initial stages, with preference for those within already protected areas.
The researchers said that protecting these sites requires less investment and intervention, while still delivering promising biodiversity returns.
They said that personal judgments are often used to select and manage invasive species and areas, but such investments rarely achieve the objective of ecological restoration.
Moreover, they suggested that a national-level policy framework should be developed to address the issue of invasive plant species in India, involving multiple stakeholders, such as forest departments, research institutions, conservation organizations, local communities, and media.
They also recommended that awareness campaigns should be conducted to educate the public about the impacts and risks of invasive plant species and how to prevent their introduction and spread.
The study's inclusion in the recent tiger report published by the government of India underscores the highest political recognition of the threat posed by biological invasions.
The researchers hoped that their findings would help inform and guide effective conservation actions to safeguard India's natural habitats and wildlife from the menace of invasive plant species.
