BharatNotes What is Invasive Alien Species?
An Invasive Alien Species (IAS) is an organism introduced outside its natural geographic range — intentionally (e.g., for ornament, fodder or fisheries) or accidentally (e.g., via trade, ballast water, packaging) — that establishes, spreads and causes harm to native ecosystems, economies or human health. The Convention on Biological Diversity (CBD) frames the obligation under Article 8(h), which calls on parties to "prevent the introduction of, control or eradicate those alien species which threaten ecosystems, habitats or species."
A key exam distinction: every invasive species is alien, but not every alien species is invasive. The "invasive" label requires demonstrable spread and harm.
Why they matter
IAS are among the principal direct drivers of biodiversity loss worldwide. They out-compete or prey on native species, alter fire and nutrient regimes, spread disease, and degrade the ecosystem services people depend on. According to the IPBES Thematic Assessment on Invasive Alien Species (approved September 2023):
| Indicator | Finding (IPBES, 2023) |
|---|---|
| Alien species introduced globally | More than 37,000 |
| Harmful invasive species among them | More than 3,500 |
| Role in recorded global extinctions | A factor in 60%; sole driver in 16% |
| Documented local extinctions linked to IAS | Over 1,200 (driven by 218 species) |
| Global economic cost | Exceeded US$423 billion per year in 2019, having at least quadrupled each decade since 1970 |
Impacts are unevenly distributed — the assessment attributed roughly 34% of reported impacts to the Americas, 31% to Europe and Central Asia, and 25% to Asia and the Pacific (IPBES, 2023). Islands are especially vulnerable, with alien plants now outnumbering native plants on more than a quarter of all islands.
India and IAS
India faces heavy ecological and economic burdens from invaders. Lantana camara — introduced as an ornamental around 1809 and listed by IUCN among the world's worst invasive species — has spread across vast tracts of natural habitat, displacing native flora and altering fire dynamics. Other widespread invaders include Parthenium hysterophorus (linked to skin and respiratory ailments) and water hyacinth (Eichhornia), which chokes wetlands and waterways. Peer-reviewed work (Biological Invasions, 2022) found India's economic losses from biological invasions are large and substantially under-reported.
Governance and the UPSC angle
India introduced its first dedicated IAS provision through Section 62A of the Wild Life (Protection) Amendment Act, 2022, empowering the Central Government to regulate or prohibit the import, trade, possession or proliferation of invasive alien species threatening wildlife or habitat. Globally, Target 6 of the Kunming-Montreal Global Biodiversity Framework (adopted December 2022) seeks to reduce the rate of introduction and establishment of priority IAS by at least 50% by 2030.
For UPSC, master the alien-vs-invasive distinction, the named Indian invaders, the IPBES headline numbers, and the CBD–WLPA–GBF governance chain.
Sources: IPBES Media Release & Assessment (ipbes.net); CBD (cbd.int); PRS India / Wild Life (Protection) Amendment Act, 2022; InforMEA Target 6; European Commission (Environment); Biological Invasions (Springer, 2022).
