[Answered]“Climate change and unprecedented floods resulting from cloud bursts have facilitated the introduction of aquatic invasive alien species into new habitats in India.” Discuss the threat posed by invasive alien species on native ecosystem and how it should be tackled.

 An alien species is a species introduced outside its natural past or present distribution; if this species becomes problematic, it is termed an invasive alien species. The climate change, movement of people and goods around the world increases the threat for introduction of invasive alien species. Invasive alien species are such a problem that Aichi Biodiversity Target 9 and one clause of UN Sustainable Development Goal 15 – Life on Land specifically address the issue. The harmful impact of invasive alien species on the natural environment, biodiversity and ecosystem services may, therefore, have direct and indirect adverse effects on human wellbeing.

Threat posed by invasive alien species on native ecosystem:

1. Invasive alien species are the most common threat to amphibians, reptiles and mammals on The IUCN Red List. Increase growth of the grass paspalum distichum has changed the ecological character of large areas of the Keoladeo National park.
2. They may lead to changes in the structure and composition of ecosystems detrimentally affecting ecosystem services, human economy and wellbeing.
3. Worldwide, invasive alien species constitute one of the leading threats to biodiversity, second only to the destruction and fragmentation of entire habitats. Papaya Mealy Bug, is believed to have destroyed the huge crops of Papaya in Assam and West Bengal.
4. Alien species may threaten indigenous species by competing with them for the same resources, by predation, by spreading diseases or parasites, or by cross-breeding with these species in the wild.
5. Alien species are also known to have changed the structure of food chains and to have affected the functioning of entire ecosystems.
6. Invasive alien species cause harmful social impacts and substantial financial losses to a variety of actors. Many invasive alien species are major pests for agriculture and forestry industries.
7. Fishing and fish farming may also suffer from the spread of invasive alien species. Alien species can also pose a health hazard or function as disease carriers.
8. Invasive alien species cause significant financial costs worldwide. In 2001, it was estimated that the annual damage caused by invasive alien species worldwide exceeded around 2 to 3% of combined global GDP.

Measures needed to control invasive alien species:

1. Building awareness and support: High awareness of risks posed by invasive alien species and about the need of prevention and mitigation for native biodiversity is needed. All the stakeholders must be actively engaged in developing best practices to prevent invasive species impacts.
2. Collecting, managing and sharing information: A clear understanding of alien species established on national territory is need to be developed to help identify species that are invasive, set priorities for research, prevention, monitoring and mitigation and rapidly detect new arrivals not already present in the country or part of the country.
3. Regional cooperation and responsibility: States need to recognize the risk that activities within their jurisdiction or control may pose to other states as a potential source of invasive alien species and take appropriate individual and cooperative actions to minimize that risk. States must act with centre and other states to prevent invasive species attacks.
4. Prevention: Countries must cooperate to strengthen and prioritize border control and quarantine measures for alien species that are or could become invasive, making best use of existing resources and information systems.
5. Early detection and rapid response: A comprehensive and cost-effective surveillance procedures must be put in place (key actions include setting up an early warning system and organizing regular surveillance of high-risk areas).
6. Mitigation of impacts: A clear draft of mitigation measures and procedures must be prepared by consulting and involve affected communities and stakeholders. Realistic priorities for eradication, containment and control are needed.
7. Restoration of native biodiversity: Strategies for eradication and control programmes must be prepared. Restoration measures for native biodiversity must be clearly planned.

A holistic approach, strategies and programmes relating to invasive alien species go beyond focus on prevention/management to promote restoration measures for native biodiversity and, wherever possible, the use of native species of local provenance. Increased resilience of native biodiversity can, in turn, provide greater protection against re-invasion or new incursions.