INVASIVE SPECIES
Environment
DEFINITION
An invasive species is any non‑native organism—plant, animal, fungus, microbe, egg or seed—that enters an ecosystem and causes environmental, economic, or health‑related harm. Since the 17th century, invasive alien species have contributed to nearly 40% of all known animal extinctions. India’s annual economic loss due to invasive species is estimated at USD 91 billion.
IMPACTS OF INVASIVE SPECIES
1. ENVIRONMENTAL IMPACTS
• Competition with native species: Invasive species displace native flora and fauna and disrupt ecological balance.
• Biodiversity loss: They dry wetlands, block sunlight, kill native plants and even alter soil chemistry.
• Food‑chain disruption: Example: Burmese Python in USA wiping out mammals needed for native predators.
• Bioaccumulation: Some species accumulate toxins which enter the human food chain (e.g., zebra mussels).
• Eutrophication: Algal invasions block light and kill aquatic life.
• Landscape change: Water hyacinth choking lakes in Bengal.
• Chemical contamination: Excessive pesticides used for control affect habitat quality.
2. ECONOMIC IMPACTS
• Agricultural damage: Invasive insects damage rice, wheat, vegetables (e.g., Japanese beetle).
• Fisheries impact: African Catfish destroys native fish breeding cycles.
• Soil fertility decline: Some species alter soil pH and chemistry.
• Infrastructure damage: Invasive plants weaken embankments, affecting irrigation structures.
REASONS FOR SPREAD
A. NATURAL FACTORS
• Wind dispersal of seeds and micro-organisms
• Ocean currents moving marine invasives
• Migratory birds transporting seeds and pathogens
• Floods carrying invasive weeds to new water bodies
B. ANTHROPOGENIC FACTORS
• Wildlife trade (example: Nilgai introduced in US became invasive)
• Introduction for pest control (Mosquitofish harming other fish)
• Transportation via ships, ballast water, airplanes
• Release of exotic pets into wild habitats
SOLUTIONS / MITIGATION
• Scientific prediction models to identify future spread zones
• Stringent wildlife trade laws
• Mandatory monitoring of imported plants/animals
• Ballast water treatment under IMO Ballast Water Convention
• Incentive-based culling (like Python culling in US)
• Mechanical removal (e.g., water hyacinth machines)
• Strong quarantine systems
• National database for tracking invasive species
• Genetic engineering for creating resilience in native species
GOVERNMENT INITIATIVES IN INDIA
• Forest Invasive Species Cell
• Plant Quarantine (Regulation of Import into India) Order 2003
• Destructive Insects & Pests Act, 1914
• Livestock Importation Act, 1898
• National Wetland Strategy (control of invasive species)
• Management Action Plans under MoEFCC
• Removal experiments (e.g., Senna spectabilis removal in Kerala forests)
INTERNATIONAL FRAMEWORKS
• Aichi Biodiversity Targets (Target 4: identification & management of IAS)
• Convention on Biological Diversity (CBD) obligations
• IUCN ISSG (Invasive Species Specialist Group)
• Global Invasive Species Database (GISD)
• Global Register of Introduced and Invasive Species (GRIIS)
NOTABLE INVASIVE SPECIES IN INDIA
• Lantana camara – Western Ghats, destroying native undergrowth
• Prosopis juliflora – Rajasthan & Gujarat, replacing native vegetation
• Giant African Snail – Damages crops from Assam to Kerala
• Water Hyacinth – Kanjli & Ropar wetlands
• Parthenium hysterophorus (Congress grass) – Causes allergies, suppresses crops
• Ashoka tree pests, papaya mealy bug etc.
STRATEGIC MITIGATION MEASURES
1. ENVIRONMENTAL
• Regeneration of lost biodiversity
• Banning bottom trawling, blast fishing
• Strict control of polluted water discharge
• Marine ecosystem preservation
2. SOCIAL
• Community participation in invasive control
• Training fishing & forest communities
• Strengthening food security
3. ECONOMIC
• Sustainable fishing opportunities
• Eco-tourism around restored ecosystems
• Diversified livelihood models
4. METHODS OF INVASIVE CONTROL
• Bio‑rock techniques for reef rehabilitation (in cases where corals are impacted)
• Asexual propagation to rebuild damaged plant communities
• Coral gardening (for reef-associated invasives)
• Structural restoration & physical removal
FUTURE PROSPECTS
• National-level awareness and education
• Immediate climate action under Paris Agreement targets
• Scientific restoration programmes (Force Blue model)
• Declaring more Marine National Parks
• Greater use of satellite mapping
• Monitoring invasive predators (e.g., starfish on coral reefs)
• Stronger legislation for invasive control
CONCLUSION
Invasive species pose one of the most severe threats to biodiversity, ecosystem stability, agriculture, fisheries, and public health. Effective policies, scientific monitoring, community engagement, and strict regulation of biological imports are essential for India to protect its ecosystems and livelihoods from invasive species threats.
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Subject: Environment
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