Environment

Invasive species

Also: invasive alien species, IAS, exotic species

Definition

Species introduced, deliberately or accidentally, outside their natural range that establish themselves, spread rapidly and harm native biodiversity, ecosystems, the economy or human health.

Summary card: Invasive species. A leading driver of biodiversity loss worldwide. India: Lantana, Prosopis, water hyacinth, Parthenium. CBD Article 8(h): prevent, control or eradicate. Kunming-Montreal Target 6: cut introduction rates by 50% by 2030. WPA amendment 2022 lets the Centre regulate invasive alien species — Summary card © UPSCPrep.in

Background and evolution

Species have always moved, but humans have accelerated this hugely through trade, travel, farming, gardening and the pet trade. Most introduced species fail to survive or remain harmless. A small proportion, however, find conditions ideal: no natural predators or diseases, plenty of resources and disturbed habitats. They then spread explosively, crowding out native species, changing soils and water flows, and sometimes causing extinction.

India's experience is typical. Lantana camara, an ornamental shrub from tropical America brought by the British in the nineteenth century, now covers large parts of India's forests, including tiger reserves, reducing grass for herbivores and fuelling forest fires. Prosopis juliflora, introduced to green dry areas and supply firewood, has taken over grasslands in Kachchh, including the Banni grasslands, and parts of Tamil Nadu. Water hyacinth, a South American aquatic plant, chokes lakes and rivers. Parthenium, believed to have arrived with imported wheat in the 1950s, causes allergies and harms crops.

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Last reviewed: 23 October 2026 · Original UPSCPrep.in content.