Invasive Species in India

Lantana camara – The Dominant Invader

Lantana camara represents India’s most widespread invasive plant, affecting 38.8% of the country’s forests. In Tamil Nadu alone, Lantana covers 185,000 hectares, with management costs estimated at $18,700 per square kilometer. The species has invaded over 300,000 sq km (44%) of Indian forests, with over 60% of tiger reserve areas affected and spreading at 500 sq km per year.​

Ecological Impact: Lantana invasion alters soil nutrients, reduces native plant density, and displetes nutritious forage species like amla, chironji, and shatavar. This creates cascading effects on herbivore populations and subsequently impacts tiger prey bases.​

Prosopis juliflora – The Arid Land Invader

Covering 56,000 hectares in Tamil Nadu, Prosopis juliflora has created significant pastoral conflicts in the Rann of Kutch by blocking migratory routes and reducing access to water sources. The species thrives in arid rangelands across Rajasthan, Gujarat, and Tamil Nadu.​

Parthenium hysterophorus – The Agricultural Menace

Parthenium causes widespread agricultural losses and poses health hazards through allergenic properties causing respiratory and skin diseases. The species shows pan-India distribution across agricultural and urban landscapes.​

Aquatic Invasives

Eichhornia crassipes (Water Hyacinth) clogs major wetlands nationwide, impacting navigation, irrigation, and fisheries. The species, along with Salvinia and Ipomea, is specifically targeted in 19 Ramsar sites under national wetland management plans.​

Marine and Coastal Invasive Species

Ballast Water Invasions

India’s 13 major and 200 non-major ports handle 95% of trade by volume, making shipping the primary vector for marine invasions. Nearly 30 invasive species have been documented from ship ballast water, with comprehensive documentation showing 32 crustacean species including 5 decapods, 6 isopods, 9 amphipods, 7 cirripedes, and 5 copepods.​

Charru Mussel Crisis

The Charru mussel (Mytella strigata), native to South America, has created severe fisheries impacts in Kerala and Tamil Nadu. In Pulicat Lake, Tamil Nadu, and Ashtamudi Lake, Kerala, the species has nearly replaced all other species. The Tamil Nadu Water Resources Department has demanded ₹160 crore from Kamarajar Port for removal operations.​

Impact Characteristics:

• High survival rate and prolific egg production​

• Survives in both marine and freshwater environments​

• Forms dense colonies affecting boat movement​

• Displaces native species and alters habitat structure​

Marine Debris Transport

A Bay of Bengal coast study documented 17 marine species transported on plastic, rubber, glass, foam, metal and wood debris. This includes the invasive Mytella strigata, highlighting the dual problem of marine pollution and invasive species transport.​

Freshwater Ecosystem Threats

Invasive Fish Species

India’s freshwater systems face invasion by 12 major alien fish species with 31% of the country providing suitable habitat. Major river basins of Pennar, Kaveri, Godavari, Krishna, and Mahanadi in central and southern India show high vulnerability.​

Critical Species Include:

• Oreochromis niloticus and Cyprinus carpio: Displacing Indian major carps from Ganga and Yamuna rivers​

• Pterygoplichthys species: Four common species (P. pardalis, P. multiradiatus, P. anisitsi, P. disjunctivus) reported from inland waters​

• Tilapia: Shows prolific breeding with parental care, multiplying every three months​

Impact Assessment: Commercial fishery of Yamuna and Ganga rivers shows 24.56% decline in local fish catches while exotic fish catches increased by 115.80% during 2010.​

Interlinking of Rivers Threat

The Interlinking of Rivers (ILR) programme poses risks of spreading invasive fish to biodiversity hotspots including the Western Ghats, northeast India, and Sundarbans delta. The programme’s 30 river connections could facilitate countrywide species homogenization.​

Economic Impact and Cost Analysis

Documented Economic Losses

The most comprehensive economic analysis reveals:

• $127.3 billion (₹8.3 trillion) documented losses over 60 years from only 10 species​

• 35% of costs from animals, 15% from plants, 1% from fungi and bacteria​

• Management costs: $18,000-19,500 per sq km for major species like Lantana​

• Only 3% of known invasive species have documented cost data​

Projected Actual Impact

Based on global GDP and population correlations, India’s actual losses could reach:

• $3.4 trillion based on GDP analysis​

• $1,700 trillion based on population analysis​

• Underreporting by 1.16 billion percent – the highest global discrepancy​

Sectoral Impact Distribution

Recent studies estimate invasive species cost the global economy $2.2 trillion since 1960, with non-native plants accounting for $926 billion in management costs. India’s contribution remains severely underestimated compared to global patterns.​

Regulatory Framework and Management Strategies

National Policy Framework

National Biodiversity Action Plan (NBAP) 2024 aligns with the Kunming-Montreal Global Biodiversity Framework, establishing comprehensive invasive species management targets. Key provisions include:​

Target 6: Invasive Alien Species Management:​

• Reduce invasive alien species impacts by 50% by 2030​

• Develop unified national quarantine systems​

• Strengthen domestic quarantine measures​

• Create national invasive species database​

• Establish early warning systems​

Legislative Measures

Wildlife Protection Amendment Bill 2021 introduces India’s first regulatory framework for invasive alien species, defining IAS as “species not native to India whose introduction may adversely impact wildlife or habitat”. However, the definition excludes native species that become invasive in new habitats within India.​

Plant Quarantine Order 2003 regulates import of plants and plant materials but requires strengthening for comprehensive species management.​

Ballast Water Management: India follows the International Maritime Organization’s BWM Convention (2017), requiring ships to manage ballast water to prevent aquatic organism transfer.​

Institutional Framework

Centre for Biodiversity Policy and Law (CEBPOL), under the National Biodiversity Authority, developed comprehensive strategies for five worst invasive plant species: Lantana camara, Prosopis juliflora, Mikania micrantha, Parthenium hysterophorus, and Eichhornia crassipes.​

Recommendations include:

• Nationally coordinated early warning system​

• Definite funding source identification​

• Periodic monitoring and inventories​

• International cooperation strengthening​

State-Level Initiatives

Tamil Nadu leads with the first dedicated invasive species removal policy, targeting 268,100 hectares affected by five major species. The state has removed invasives from 4,185 hectares using Tamil Nadu Newsprint and Papers Limited for wood utilization.​

Forest College and Research Institute (TNAU) organized international workshops to develop policy recommendations for integrated management approaches.​

Management Challenges and Future Directions

Knowledge Gaps

• 97% of invasive species lack economic impact data​

• Central, Eastern, and Northeast India show “silent impact” with no cost reports​

• Marine invasive species impact assessment remains inadequate​

• Taxonomic gaps particularly for microbial and marine invasives​

Integrated Management Approach

Successful management requires:

• Early detection and rapid response systems​

• Community involvement and awareness​

• Restoration with native species post-removal​

• Economic incentivization through value-addition of invasive biomass​

• Regional cooperation for uniform quarantine measures​

Climate Change Interactions

Rising temperatures and human disturbances facilitate invasions in previously resilient higher Himalayan regions. Climate-driven range expansions require adaptive management strategies incorporating future climate scenarios.​

Recommendations for Enhanced Management

Immediate Actions

1. Establish national invasive species coordination center with dedicated funding​

2. Strengthen ballast water management at all major ports​

3. Develop comprehensive economic impact assessment for all 330 known invasive species​

4. Implement integrated management for priority species across affected landscapes​

Long-term Strategy

1. Create predictive modeling systems for invasion risk assessment​

2. Develop native species restoration programs for degraded ecosystems​

3. Establish regional cooperation frameworks with neighboring countries​

4. Integrate invasive species management with climate adaptation strategies​

Research Priorities

1. Economic valuation of ecosystem services lost to invasions​

2. Climate-invasion interaction modeling​

3. Community-based management effectiveness assessment​

4. Biocontrol potential for major invasive species​

Conclusion

India’s invasive species crisis represents a national emergency requiring immediate, coordinated action across multiple sectors. With documented losses of ₹8.3 trillion potentially representing only 3% of actual costs, the true economic and ecological impact could exceed ₹280 trillion. The threat to 66% of natural systems and critical biodiversity hotspots demands urgent implementation of comprehensive management strategies, enhanced regulatory frameworks, and substantial investment in prevention, early detection, and control measures.

Success depends on integrating scientific research, policy implementation, community engagement, and international cooperation to address this unprecedented challenge to India’s biodiversity and economic security. The window for effective action is rapidly closing, making invasive species management a critical priority for India’s sustainable development and conservation goals.

ENVIRONMENT 

THE HINDU