Trade may open doors to Invasive Alien Species

Context: Shifting trade agreements and new ties between previously unlinked nations may further increase the spread of new invasive alien species between continents.

Freight transport between growing economies is projected to triple by 2050, especially maritime and air cargo transport, increasing invasion risk by reducing travel time and improving the survivability of alien species.

What are Invasive Alien Species?

• They are non-native species introduced (intentionally or accidentally) into new environments where they cause harm.
• They outcompete native species, disrupt ecosystems, and harm human livelihoods and health.
• E.g., Giant African snail arrived in India around the 1870s, displaced native snails, damaged crops and ecosystems, and spread the rat lungworm parasite, threatening human and wildlife health.

How do Invasive Alien Species enter? 

The introduction of these exotic species can be deliberate or accidental.

Deliberate Introduction (Biocontrol): 

• Gambusia (mosquitofish), Poecilia reticulata (guppies), and Pterophyllum scalare (angelfish)- introduced for mosquito control and ornamental trade.
• Tilapia- introduced to boost food security, but has outcompeted native freshwater species.

Accidental Introduction (Biofouling, Trade & Transport): 

• Parthenium grass- entered into India with the US wheat imports under the PL-480 ‘Food for Peace’ programme in 1955.
• Giant African snail- likely arrived around the 19th century through East African trade.
• Asian paddle crab- introduced to New Zealand via biofouling in ballast water. 

Biofouling: 

• When ships travel between countries without cargo, they are filled with ballast water to help the ship stay stable on the high seas. 
• Biofouling is the undesirable accumulation of plants, animals, and algae on surfaces, sometimes during the filling and flushing of ballast water, which can transport exotic species from one region to another. 
• E.g., The Asian paddle crab was introduced from the Northwest Pacific and East Asian waters to New Zealand, where it carries the white-spot syndrome virus, via Biofouling.

Impacts on India

• A 2022 study found that India has lost $127.3 billion (₹830 crore) to invasive alien species over the last 60 years. This makes India, the second-most financially affected nation by invasive alien species in the world, after the US.
• The estimate is based on costs from only 10 out of 2,000+ invasive species in India. Economic impacts are known for just 3% of these species; data for the rest is incomplete or missing.
• Semi-aquatic and aquatic invasive alien species pose a greater fiscal burden than terrestrial species as they often affect high-value sectors like public health, water infrastructure, and fisheries.
• E.g., The yellow fever mosquito is the most financially damaging invasive semi-aquatic species in India. It poses threats to both public health and the economy.

Way Forward

To reduce the risk of importing invasive alien species, India needs to: 

• Strengthen National Policy: Enforcing stricter biosecurity at ports and other entry points and developing real-time species-tracking and early-warning systems that can catch invasion events before they get out of control.
• Stronger Collaboration between government departments and researchers to track potentially invasive species and their spread under changing climate and trade patterns.
• Mandatory Implementation of post-trade biological impact assessments, typically in quarantine facilities managed by the respective departments.

Strengthening policies to reduce the spread of invasive species is one step towards managing their consequences on native biodiversity. Like One Health, the implementation of a ‘One Biosecurity’ framework will better our chances of managing invasive alien species.