Invasive Species Threaten India’s Biodiversity, Say Scientists

Conservation scientists are raising alarm over the growing spread of ‘stealth invader’ species that are threatening biodiversity and altering ecosystems across India and the world.
Invasive alien species (IAS) are non-native organisms introduced—intentionally or accidentally—into new environments. They often arrive as exotic ornamental plants, aquarium fish, or land-revegetation solutions, but soon establish themselves and outcompete native flora and fauna.

Global and National Impact

According to K.V. Sankaran, former Director of the Kerala Forest Research Institute (KFRI), around 37,000 alien species have become established globally due to human activity, with 200 more added each year.
India alone harbours an estimated 139 invasive alien species, most of them insect pests of crops, with others indirectly harming agriculture by disrupting native insect populations.

Examples of Invasive Species

• Yellow Crazy Ant (Anoplolepis gracilipes): This invasive ant reduces populations of native ants that naturally control crop pests.
• Lantana camara: Introduced during the British colonial period as a decorative shrub, it now blocks elephant corridors and disrupts habitats of large herbivores.
• Prosopis juliflora: Brought to India from South America and the Caribbean in the 19th century, and later planted in Gujarat’s Banni grassland to combat soil salinity, it now covers 50–60% of the original grassland, earning the local name ‘Gando Bawar’ (mad tree).

Aquatic Ecosystems Under Threat

India’s water bodies face similar challenges from invasive aquatic weeds, including:

• Water hyacinth (Pontederia crassipes)
• Alligator weed (Alternanthera philoxeroides)
• Duckweed (Lemnoideae species)
• Water lettuce (Pistia stratiotes)

Water hyacinth, among the world’s 10 worst invasive species, has spread widely—from paddy fields and village ponds to major wetlands and even the Kaziranga National Park in Assam, affecting both agriculture and migratory bird habitats.

Urgent Call for Action

Experts warn that unchecked invasion by these alien species could irreversibly damage local biodiversity, disrupt ecosystems, and undermine conservation efforts. They urge for early detection, scientific management, and public awareness to curb further spread.

Source: TH