IAS Gyan

Daily News Analysis


9th October, 2023 Environment

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Picture Courtesy: www.thenewsminute.com

Context: The National Green Tribunal's decision to seek a comprehensive report on the removal of the invasive mussel species, Mytella strigata,  in the Ennore-Pulicat wetland is a crucial step in addressing the ecological threat posed by invasive species.

Key Highlights


The Ennore-Pulicat wetland, a vital ecological area, is facing a significant threat due to the rapid proliferation of an invasive mussel species, Mytella strigata, known locally as kaaka aazhi.

This South American mussel variety has spread extensively, covering the riverbed and hindering the natural behaviour of local species like prawns, yellow clams (manja matti), and green mussels (pachai aazhi).

The situation has been brought to the attention of the National Green Tribunal (NGT) through an application filed by residents.

Complainant's Concerns

Impact on Local Species:  The invasive mussels have formed a dense carpet on the riverbed. This growth is preventing prawns from grazing and burying themselves in the sediment, disrupting their natural habitat and behaviour.

Commercial Impact: Apart from prawns, the invasive mussels are adversely affecting commercially valuable species such as yellow clams and green mussels, which are vital for the local economy.

Environmental Impact: The spread of these mussels has led to the formation of a deep layer of sludge, one foot in depth, consisting of black, foul-smelling slimy excreta. This situation is causing severe environmental degradation in the affected area.

Government's Response

The government pleader argued that the kaaka aazhi species is not an alien species. According to their argument, this species is listed in the Wildlife Protection Act, 1972 (WPA), indicating that it is not an invasive entity.

The government's stance raises a jurisdictional question, implying that the NGT might not have the authority to handle matters related to the WPA, as it is not listed in Schedule I of the NGT Act.

NGT's Response and Directives

The NGT Bench, acknowledging the legal complexity of the matter, ordered the Fisheries Department and the Tamil Nadu State Wetland Authority to provide a detailed report. This report is expected to include information about ongoing dredging activities and any action plans prepared to address the spread of the invasive mussel species.

The NGT Bench remarked that the jurisdictional aspect concerning the Wildlife Protection Act needs further examination, indicating that this legal matter will be explored in future hearings.

Implications and Significance

Ecological Impact: The unchecked proliferation of invasive species can severely disrupt local ecosystems, leading to imbalances in the natural habitat and threatening biodiversity.

Economic Consequences: Beyond the environmental concerns, the invasion of these mussels jeopardizes the livelihoods of local communities dependent on fishing and related activities.

Legal Precedent: The case sets a precedent for addressing jurisdictional challenges concerning invasive species within the framework of existing wildlife protection laws, balancing the need for conservation with legal regulations.

Invasive Species


  • Invasive species, also known as alien or exotic species, are organisms that are introduced to a new environment, often by human activities.
  • These species lack natural predators or controls in their new habitat, allowing them to reproduce and spread rapidly.
  • They can be plants, animals, fungi, or microorganisms.
  • The introduction of invasive species can upset the ecological balance of an area, leading to reduced biodiversity and significant economic and environmental consequences.


  • The impact of invasive species in India is significant and multifaceted, affecting various aspects of the country's environment, biodiversity, economy, and human health.
  • Biodiversity Loss: Invasive species often outcompete native species for resources, leading to a decline in native plant and animal populations. This competition can result in the extinction or endangerment of indigenous species, reducing the overall biodiversity of affected ecosystems.
  • Disruption of Ecosystems: Invasive species can disrupt natural ecosystems by altering nutrient cycling, fire regimes, and water availability. These disruptions can negatively impact other species in the ecosystem, leading to imbalances and ecological instability.
  • Agricultural Impact: Invasive species, such as the fall armyworm, can damage crops, leading to reduced agricultural yields. This affects food security, farmer livelihoods, and the overall economy. Invasive plants can also infest agricultural lands, reducing the productivity of farmlands.
  • Impact on Water Bodies: Aquatic invasive species like water hyacinth and African catfish can choke water bodies. This reduces water quality, disrupts aquatic ecosystems, hampers fishing activities, and affects the availability of clean water for human consumption and agriculture.
  • Health Impacts: Some invasive species can carry diseases that are harmful to humans, animals, and plants. For instance, invasive mosquitoes can spread diseases like dengue fever, malaria, and chikungunya, posing a direct threat to public health.
  • Economic Losses: The economic impact of invasive species includes costs related to agricultural losses, healthcare expenditures due to diseases spread by invasives, and expenses associated with controlling and managing these species. Invasive species can also damage infrastructure, such as roads and buildings, leading to additional economic burdens.
  • Loss of Indigenous Knowledge: Invasive species can replace native plant species used in traditional medicine and cultural practices. This leads to a loss of indigenous knowledge about the uses of native plants, affecting traditional healthcare systems and cultural heritage.
  • Tourism and Recreational Activities: Invasive species can negatively affect natural landscapes and biodiversity, diminishing the appeal of tourist destinations. Additionally, invasive species in recreational areas, such as parks and lakes, can hinder outdoor activities and impact tourism revenue.

Some of the invasive species in India

Water Hyacinth

Origin: Native to South America.

Effect: Water hyacinth forms dense mats on water bodies, blocking sunlight and reducing oxygen levels, which harms aquatic life. It obstructs waterways, making navigation and fishing difficult. Additionally, it hampers irrigation and affects agricultural productivity.


Origin: Native to the Americas.

Effect: Lantana is a highly invasive shrub that forms impenetrable thickets, preventing the growth of native vegetation. This reduces biodiversity, affects animal habitats, and inhibits the regeneration of forests and grasslands. Its leaves are toxic, making it unsuitable for livestock consumption.

African Catfish

Origin: Native to Africa.

Effect: African catfish are aggressive predators that disrupt local aquatic ecosystems by preying on native fish and other aquatic organisms. This predatory behaviour can lead to a decline in native fish populations, upsetting the balance of the ecosystem.

Parthenium Weed

Origin: Native to North America.

Effect: Parthenium weed is allelopathic, releasing chemicals that inhibit the growth of other plants. It displaces native vegetation, reducing forage for livestock and affecting agricultural productivity. Additionally, its pollen causes respiratory allergies in humans and livestock.

Prosopis juliflora

Origin: Native to South America.

Effect: Prosopis juliflora invades drylands, displacing native vegetation. It consumes large quantities of water, leading to soil salinity and reduced soil fertility. Its thorny nature makes it difficult to clear, impacting agricultural practices and grazing lands.


Origin: Native to Central and South America.

Effect: Mikania grows rapidly and forms dense thickets, smothering native vegetation and reducing biodiversity in forests. Its aggressive growth inhibits natural regeneration and disrupts the ecological balance of affected areas.

Apple Snail

Origin: Native to South America.

Effect: Apple snails feed on aquatic plants, damaging rice crops and affecting agricultural yields. Their voracious appetite makes them a threat to rice paddies, impacting food security and the economy.


Origin: Native to South America.

Effect: Salvinia forms dense floating mats, blocking sunlight and oxygen from reaching the water. This disrupts aquatic ecosystems, depleting oxygen levels and impacting fish and other aquatic life. It also hampers water transportation and affects the livelihoods of fishing communities.


Origin: Native to Central and South America.

Effect: Mimosa invades wetlands and waterways, displacing native plants. Its dense growth disrupts natural habitats, reduces biodiversity, and alters the structure of affected ecosystems.

Red-vented Bulbul

Origin: Native to South Asia.

Effect: The red-vented bulbul competes with native bird species for resources, including nesting sites and food. This competition can lead to declines in native bird populations, affecting biodiversity and potentially disrupting local ecosystems.

Acacia species

Origin: Native to Australia, Africa, and Asia.

Effect: Certain Acacia species become invasive, displacing native vegetation. They alter soil composition and structure, affecting the growth of native plants and disrupting natural habitats.


  • Lack of Awareness: Many people, including policymakers, may not fully understand the impact and risks posed by invasive species, hindering the implementation of effective policies.
  • Globalization: Increased international trade and travel facilitate the accidental introduction of invasive species, making it difficult to regulate their entry.
  • Climate Change: Altered climate patterns can create new habitats suitable for invasive species, expanding their range and making them harder to control.
  • Limited Research: There is a need for comprehensive research on invasive species to understand their behaviour, ecological impacts, and potential control methods in the context of Indian ecosystems.
  • Resource Constraints: Limited funds, manpower, and infrastructure hinder the development and implementation of robust invasive species management strategies

Way Forward to address the challenges posed by invasive species


Strict Regulations: Enforcing stringent regulations on the importation of plants, animals, and other potentially invasive species is crucial. This includes proper quarantine protocols and border controls.

Public Awareness: Educating the public, industries, and policymakers about the risks associated with invasive species is essential. Awareness campaigns can promote responsible behaviours.

Early Detection: Developing systems for early detection and rapid response to new invasive species arrivals is vital to prevent their establishment and spread.


Research and Monitoring: Investing in research to understand the behaviour and impact of invasive species is fundamental. Regular monitoring programs can track their spread and assess the effectiveness of control measures.

Biological Control: Introducing natural predators or diseases specific to invasive species can help control their population without harming native species.

Mechanical and Chemical Control: Utilizing methods like manual removal or targeted chemical control, under strict supervision, can be employed to manage invasive species. However, this must be done with care to minimize collateral damage.

Restoration and Conservation

Ecosystem Restoration: Restoring degraded ecosystems can enhance their resilience against invasive species. Healthy ecosystems are more resistant to invasions.

Conservation Efforts: Protecting and conserving native species and their habitats is crucial. Preserving biodiversity makes it harder for invasive species to establish themselves.

International Cooperation

Collaboration: Collaborating with neighbouring countries and international organizations is essential. Sharing knowledge, technologies, and best practices can enhance the collective ability to manage invasive species.

Policy Harmonization: Working towards harmonizing policies related to invasive species can ensure consistent regulations and responses, particularly in regions with porous borders.

Research and Innovation

Innovation: Encouraging innovation in the development of new techniques and technologies for invasive species management is vital. This includes exploring advanced biological control methods and sustainable chemical alternatives.

Capacity Building: Investing in training and building the capacity of scientists, policymakers, and local communities is necessary. A well-informed and skilled workforce is essential for effective invasive species management.


  • The case before the NGT underscores the complexity of managing invasive species within legal boundaries, emphasizing the need for a holistic approach that combines scientific understanding, legal considerations, and timely, effective action to preserve fragile ecosystems and the communities reliant on them. The future hearings and the NGT's decisions in this case will likely have far-reaching implications for similar issues in India's ecological landscape.

Must Read Articles:

National Green Tribunal (NGT):  https://www.iasgyan.in/daily-current-affairs/national-green-tribunal-8


Q. The term “Mytella strigata” is frequently seen in the news, it is related to:

A) A type of fish found in freshwater bodies

B) A species of invasive mussel

C) A type of edible seaweed

D) A marine mammal species

Answer: B



Q. What are the ecological and economic impacts of invasive species, and what strategies can be employed to effectively manage and control their spread in natural ecosystems?