Invasive Species: The Hidden Invaders

How plants and animals introduced to new places spread out of control, the huge economic costs they cause, and what can be done.

Invasive species are plants, animals or microorganisms introduced, often by humans, to places where they didn’t naturally occur, and which spread rapidly, causing harm.

The global cost

In 2023, a major assessment by IPBES estimated that the costs of invasive species exceed 423 billion dollars a year globally, and that these costs have roughly quadrupled every decade since 1970.

Examples in India

Lantana camara, an ornamental shrub from the Americas introduced during colonial times, has spread across large parts of India’s forests, crowding out native plants and reducing food for wildlife.
Water hyacinth clogs lakes and rivers, blocking boats, harming fisheries and breeding mosquitoes.
Prosopis juliflora, a tree introduced to provide fuelwood, invaded grasslands and dry areas.
Fall armyworm, a crop pest from the Americas, arrived in India in 2018 and attacked maize crops.

Economic effects

Agriculture: crop pests and weeds reduce yields.
Fisheries and water supply.
Health: some invasive species spread disease.
Biodiversity loss: invasive species are a major cause of extinctions.
Control costs for removal and management.

How they spread

Trade: pests hitchhike in shipments.
Deliberate introduction for gardens, pets or forestry.
Travel and ballast water in ships.

Prevention is cheaper

Once established, invasive species are costly or impossible to remove. Prevention through biosecurity, border inspections and quarantine is far cheaper.

Turning invaders into resources

Some communities make products from invasive species, such as furniture and crafts from lantana, or biogas and handicrafts from water hyacinth, turning a problem into income.

The clogged lake

Water hyacinth spreads across a lake near a city, choking fish and blocking boats. The city spends heavily on removal each year. A local group trains women to make baskets and mats from the harvested plants, earning income while helping clear the lake.

Thinking introduced species are always harmless or beneficial

Many introduced species become invasive, causing costs estimated at over 423 billion dollars a year globally.

Key takeaways

Invasive species are introduced organisms that spread and cause harm.
IPBES estimated global costs above 423 billion dollars a year in 2023.
Lantana, water hyacinth and fall armyworm affect India.
Prevention through biosecurity is far cheaper than removal.