Invasive Alien Species (IAS): Definition, Examples, Impacts, and Management in India
Relevant for UPSC Prelims GS Paper 1 (Environment & Ecology – Biodiversity, Conservation) and GS Paper 3 (Environmental Issues and Management).
Invasive Alien Species (IAS) are organisms introduced intentionally or accidentally into regions beyond their natural habitats, where they establish, spread rapidly, and cause harm to native biodiversity, ecosystems, agriculture, economy, and human health. Understanding IAS is crucial for UPSC aspirants as this topic links environment, ecology, biodiversity conservation, and sustainable development.
What are Invasive Alien Species?
According to the Convention on Biological Diversity (CBD), IAS are species whose introduction or spread outside their natural range threatens biological diversity. They include plants, animals, fungi, pathogens, and microorganisms characterized by their ability to “arrive, survive, and thrive” in new environments, often outcompeting native species for resources such as food, water, and habitat.
In India, the Wildlife Protection Act (Amended 2022) defines IAS as species not native to India whose introduction or spread may adversely impact wildlife or habitat.
Common Examples of Invasive Alien Species in India
- Flora:
- Lantana camara: A highly invasive shrub forming dense thickets, displacing native vegetation.
- Parthenium hysterophorus (Congress weed): Invades grasslands and farmlands, reducing productivity.
- Water hyacinth (Eichhornia crassipes): Chokes water bodies, impacting aquatic biodiversity.
- Prosopis juliflora: Introduced for afforestation but now a threat to native flora in dry regions.
- Fauna:
- African catfish (Clarias gariepinus): Introduced for aquaculture, it preys on native fish species.
- Chital (Spotted deer): Introduced in Andaman Islands, they lack natural predators and overgraze native plants.
- Papaya Mealy Bug: A pest damaging papaya crops in northeastern states.
- House Crow: Native to mainland India but invasive in Andaman and Nicobar Islands.
Ecological and Economic Implications
- Biodiversity Loss: IAS outcompete native species for resources, resulting in reduced biodiversity and altered ecosystem dynamics.
- Disruption of Ecosystem Functions: Changes in nutrient cycling, soil composition, and water availability.
- Agricultural Damage: Crop losses due to pest species and invasive weeds, impacting livelihoods.
- Health Risks: Some IAS act as vectors for diseases or cause allergic reactions.
- Economic Burden: Control and management of IAS cost billions, diverting resources from other development goals.
Causes of the Spread of IAS
- Global trade and transport accelerates unintentional introduction.
- Deliberate introduction for agriculture, aquaculture, and ornamental purposes.
- Climate change creates favourable conditions for IAS establishment.
- Lack of strict quarantine and biosecurity measures.
Management and Control Strategies in India
- National Action Plan on Invasive Alien Species: Focuses on prevention, early detection, control, and management.
- Legal provisions under the Wildlife Protection Act to regulate and prohibit trade and proliferation.
- Restoration of native habitats and biocontrol agents like insects and fungi targeted at specific IAS.
- Public awareness and stakeholder participation in monitoring and management.
- Research and database development like the National Biodiversity Authority’s invasive species list.
- International cooperation aligned with the Kunming-Montreal Global Biodiversity Framework (2022) to reduce IAS introduction.
Conclusion
Invasive Alien Species pose a multifaceted threat to India’s rich biodiversity, ecosystems, and economy. Addressing this challenge requires coordinated multi-sectoral approaches, policy implementation, scientific research, and awareness campaigns. For UPSC aspirants, mastering this topic deepens understanding of ecological balance, conservation issues, and sustainable development in India.
