Invasive species

noun phrase (countable; plural unchanged)

/ɪnˈveɪ.sɪv ˈspiː.ʃiːz/

A non-native (alien or exotic) species that, when introduced into a new environment, spreads aggressively, outcompetes native species, and causes measurable harm to local biodiversity, ecosystems, economies, or human health. The IUCN identifies invasive species as the second leading cause of global biodiversity loss after habitat destruction. In India, notable examples include Lantana camara (shrub invading forest undergrowth), Eichhornia crassipes (water hyacinth choking wetlands), and Prosopis juliflora (mesquite degrading grassland), all of which are subject to management programmes under National Biodiversity Authority guidelines.

✍️ Usage in a UPSC answer

The rampant spread of Lantana camara across Mudumalai Tiger Reserve has significantly reduced the availability of native forage for sambar deer, indirectly depressing prey density for resident tiger populations.

Synonyms

alien speciesexotic speciesnon-native speciesintroduced speciespest species

Antonyms

native speciesendemic speciesindigenous species

🌱 Word Family

invade (verb), invasion (noun), invasiveness (noun), alien species (noun phrase), naturalised species (noun phrase)

🔡 Root

Latin invasivus from invadere = to invade (in- = into + vadere = to go); Latin species = appearance, kind

📜 Etymology

The ecological term 'invasive species' was popularised by British ecologist Charles Elton in his seminal 1958 work The Ecology of Invasions by Animals and Plants, which first systematically described biological invasions as an ecological phenomenon. 'Invasive' derives from Latin invadere (to go into, attack).

🧠 Memory Hook

INVASIVE = INVADE. An invasive species invades a new land like a conqueror — it arrives, spreads, and pushes out the locals. Water hyacinth invades Indian lakes exactly as an army invades territory: rapidly, relentlessly, and with devastating effect on the existing order.

📝 Seen in UPSC Question Papers

Prelims 2023 — Biodiversity
Prelims 2019 — Ecology
Prelims 2012 — Wildlife Conservation
Prelims 2011 — Biogeography

Real UPSC previous-year questions whose text uses “Invasive species” — proof this word earns its place on your list.

🌿 Environment & Ecology 📖 Seen in: Ecology Fundamentals — Ecosystems, Foo...

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