Invasive Alien Species

Syllabus
GS Paper 3 – Conservation, Environmental Pollution and Degradation, Environmental Impact Assessment.

Context
Among the seven countries in South Asia, India holds the distinction of having the largest land area and is home to 185 invasive alien plant species.

Invasive Alien Species

Table of Contents

Introduction

Invasive alien species pose a significant threat to global biodiversity, ecosystems, and human well-being. The surge in globalization, heightened trade, and human movement has intensified the proliferation of these invasive species, necessitating urgent attention and comprehensive management strategies. Notably, 34% of the impacts of biological invasions are reported in the Americas, 31% in Europe and Central Asia, 25% in Asia and the Pacific, and approximately 7% in Africa. The majority of these negative effects manifest on land, particularly in forests, woodlands, and cultivated areas. Islands, in particular, bear the brunt of invasive species, with over 25% of all islands now hosting more alien plants than native ones. Furthermore, 85% of the impacts of biological invasions on native species are detrimental.

Definition: Invasive species are non-native organisms that can inflict damage on the ecosystem, economy, or human health when introduced into a new environment. They often outperform or adversely affect native species, disrupt natural processes, and can lead to significant ecological imbalances. They can be plants, animals, fungi, or even microbes.
Terrestrial Invasive Species: These refer to non-native plants, animals, fungi, or microorganisms that have been introduced to and established in terrestrial ecosystems. These ecosystems include land-based environments such as forests, grasslands, deserts, and urban areas.
Aquatic Invasive Species: These are non-native plants, animals, microbes, and pathogens that have been introduced into aquatic ecosystems. This includes both freshwater and marine environments.
Invasiveness Criteria: Not all non-native species are invasive. To be classified as invasive, a species must easily adapt to the new area, reproduce rapidly, and harm property, the economy, or the native plants and animals of the region.
Historical Propagation: The number of species being introduced into new areas is increasing due to the rise in global movement of people and goods, the opening of new trade routes, and enhanced transportation. A study in 2017 found that over one third of all introductions in the past 200 years occurred after 1970.
Human Modifications: This refers to changes made by humans to natural landscapes, ecosystems, or habitats through activities such as urbanization, deforestation, and agricultural expansion. These modifications create new opportunities for invasive species to thrive.
Shifting Soil Moisture Regimes: Invasive species may gain a competitive edge in altered soil moisture conditions. Species adapted to drier or wetter soils may thrive when these conditions change, allowing them to outcompete native species.
Altered Cycle of Natural Disturbances: Changes in the frequency or intensity of natural disturbances like wildfires may favor invasive species that are adapted to such disturbances, allowing them to outcompete native species.

Key features of Invasive alien species

Origin from Foreign Lands: Invasive species are not native or indigenous to a specific location. Instead, they are introduced to a new area either intentionally or unintentionally through human activities such as agriculture, horticulture, aquaculture, pet trade, or transportation (for example, ballast water discharge from ships).
High Reproductive Speed: Invasive species often exhibit high reproductive rates, which allows them to proliferate rapidly in their new environment.
Absence of Natural Predators: Invasive species thrive due to the lack of competition and predation pressure, as they are introduced without their natural predators from their native habitat.
Adaptability to Ecological Conditions: Invasive species possess a wide range of environmental adaptability. This allows them to survive in diverse conditions, such as extreme temperatures, pH levels, or disturbances like fire or floods, enhancing their survivability.
Ecosystem Dynamics Modification: Invasive species have the ability to alter ecosystem processes, such as nutrient cycling and fire regimes. This can lead to changes in habitat structure and biodiversity.

Prominent examples of Invasive Alien Species in India

Lantana Invasion: Lantana (Lantana Camara) is a highly invasive shrub that forms dense thickets, outcompeting native vegetation. It is prevalent in various parts of India, particularly in the Western Ghats.
Water Hyacinth Proliferation: Water Hyacinth (Eichhornia Crassipes) is an aquatic plant that proliferates rapidly, forming dense mats on water surfaces. It is common in water bodies across India.
Prosopis Juliflora Spread: Prosopis juliflora (Vilayati Keekar) is an invasive plant that has spread rapidly across India, leading to the degradation of native ecosystems. It is found in arid and semi-arid regions.
Needle Bush Distribution: Originating from South America, the Needle Bush is now distributed throughout India. It is found in thorny scrub and dry degraded forests, often creating close thickets.
Black Wattle Introduction: Black Wattle, originating from South East Australia, was introduced for afforestation in the Western Ghats region. It regenerates rapidly after fire and forms dense thickets.
Goat Weed Colonization: Goat Weed, originating from America, acts as an aggressive colonizer. It is a troublesome weed in gardens, cultivated fields, and forests, affecting the native species.
Prickly Poppy Colonization: Prickly Poppy also acts as an aggressive colonizer. It is a winter-season weed found in cultivated fields, scrublands, and fringes of forests.
Touch-Me-Not Plant Distribution: The Touch-Me-Not Plant or Sleeping Grass, originating from Brazil, is a common weed of cultivated fields, scrub lands, and degraded forests. It is distributed throughout India.
4 ‘0’ Clock Plant Invasion: The 4 ‘0’ clock plant, originating from West Asia, runs wild in gardens and near habitation. It is distributed throughout India.
Black Mimosa Invasion: Black Mimosa, originating from North America, invades water courses and seasonally flooded wetlands. It is distributed in the Himalayas and Western Ghats.

Status of Invasive Alien Species

Invasive Alien Flora Inventory: For the first time, scientists from India and six other countries have compiled an inventory of 241 plants that were introduced in South Asian countries and have over time become Invasive Alien Species (IAS).
Country-wise Invasive Species: India, with its largest land area among the group of seven countries, tops the list with 185 invasive alien plants listed by the team. It is followed by Bhutan (53), Sri Lanka (45), Bangladesh (39), Nepal (30), and Pakistan (29). The Maldives has the fewest invasive plants with just 15 species.
Major Contributors of Invasive Species: The major contributors of invasive species are Southern America, Northern America, Africa, and Europe.
Introduction Pathways of Alien Species: The introduction of alien species occurs through various pathways: escape pathway (40%), stowaway such as in ballast water of ships (24%), and released into the environment (21%).
Restricted Invasive Species At least 150 plant species of the 241 identified were still restricted to a single country.

IPBES report – Highlights

The Intergovernmental Platform on Biodiversity and Ecosystem Services (IPBES) has recently published an “Assessment Report on Invasive Alien Species and their Control.” This comprehensive study highlights the alarming spread of invasive alien species worldwide and their devastating impact on global biodiversity.

Magnitude of Alien Species Invasion: The report discloses the existence of approximately 37,000 alien species, introduced by human activities, across various regions and biomes. More than 3,500 of these are classified as invasive alien species, posing severe threats to local ecosystems.
Invasive Alien Species Statistics: About 6% of alien plants, 22% of alien invertebrates, 14% of alien vertebrates, and 11% of alien microbes are known to be invasive.
Dominant Invasive Species: The water hyacinth is ranked as the world’s most widespread invasive alien species on land. Lantana, a flowering shrub, and the black rat hold the second and third positions on the global invasion scale. The brown rat and house mouse are also widespread invaders.
Intentional Introduction of Invasive Species: Many invasive alien species were intentionally introduced for perceived benefits in sectors such as forestry, agriculture, horticulture, aquaculture, and as pets.
Role of Invasive Species in Extinctions: Invasive alien species have played a significant role in 60% of documented global plant and animal extinctions.
Invasive Species as Biodiversity Loss Drivers: These species are now recognized as one of the five primary drivers of biodiversity loss, alongside land and sea use change, direct exploitation of organisms, climate change, and pollution.
Negative Impacts of Invasive Species: Nearly 80% of the documented impacts of invasive species on nature’s contribution to people are negative.

Factors responsible for growth of Invasive Alien Species

Impact of Globalization and Trade: The surge in the movement of goods and people around the world due to globalization has facilitated the easy infiltration of invasive species into new ecosystems. For instance, ships carrying ballast water can transport aquatic organisms across oceans, while planes and cars can unknowingly transport insects, seeds, and other plant material.
Climate Change and Invasive Species: Rising temperatures and shifting weather patterns due to climate change create new habitats that are suitable for invasive species. For example, warmer winters enable insects like the Asian longhorned beetle, native to eastern Asia, to survive in colder regions, posing a threat to hardwood forests.
Habitat Degradation and Invasive Species: Construction projects, deforestation, and unsustainable land-use changes have led to the expansion of human settlements and urban areas. This disrupts and degrades native ecosystems, making it easier for invasive species to establish themselves in disturbed habitats.
Economic Introductions of Invasive Species: Some invasive species were intentionally introduced for economic purposes, such as agriculture, aquaculture, or ornamental plants. However, these species can lead to unintended ecological consequences as they outcompete or negatively interact with native organisms.
Inadequate Biosecurity Measures: Weak biosecurity measures, such as inadequate inspection protocols for imported goods, ineffective quarantine practices, and insufficient regulations on the movement of potentially invasive species, have contributed to their spread.
Lack of Awareness and Invasive Species: Public ignorance, inadequate management strategies, and insufficient funding and resources for research, monitoring, and eradication programs have further exacerbated the spread of invasive alien species.

Impacts of Invasive Alien Species

Ecological Consequences:
- Invasive species can outcompete native species, leading to a decline in their populations and even causing species extinction.
- Invasive plants can alter soil composition, nutrient cycling, and fire regimes, making survival difficult for native vegetation.
- They can disrupt food webs, change predator-prey relationships, and alter the energy flow within an ecosystem. For instance, Cane toads secrete skin with harmful bacteria, harming native predators that attempt to eat them.
Biodiversity Loss: According to the IUCN Red List of Threatened Species, invasive alien species (IAS) are one of the top causes of biodiversity loss and the second most common cause of species extinctions.
Economic Ramifications:
- Invasive species can damage crops, trees, and livestock, leading to food insecurity and decreased income for rural communities.
- Some invasive species, like termites or rodents, can damage infrastructure like roads and bridges, costing millions in repairs and maintenance. For example, Zebra mussels attach to surfaces such as pipes or boat hulls, causing damage to infrastructure.
- They have substantial economic costs, affecting not only local ecosystems but also water, biology, and security. The estimated global cost of invasive species was 423 billion dollars with costs increasing fourfold every decade since 1970.
Health Implications:
- Invasive species can act as vectors for diseases like West Nile virus or Lyme disease. For example, the Giant African land snail has become a pest in agriculture, which poses a risk of transmitting diseases to humans. These species can pollute water bodies, leading to various health impacts.
- IAS pose a threat to human health directly or indirectly. The Asian tiger mosquito (Aedes albopictus), native to South-East Asia, is a vector of a number of human diseases such as Dengue fever and West Nile virus.
Cultural and Recreational Effects: Invasive plants may alter the aesthetics of landscapes, impacting recreational experiences. This, in turn, affects the tourism sector and local economies that rely on this sector.
Species Extinction: IAS alone have contributed either solely or alongside other drivers, to 60% of recorded global extinctions. Islands are particularly vulnerable as 90% of global animal and plant extinctions are occurring here.
Impact on Vulnerable Populations: The economic costs are disproportionately borne by poor and disadvantaged populations living in degraded environments heavily infested by alien species.
Impact on India: A study indicates that about 66% of India’s natural systems are threatened by invasive species. They negatively impact ecosystems crucial for the survival of apex predators like tigers.
Reduced Navigation:
- Water hyacinth, native to South America, has been intentionally introduced around the world for ornamental purposes and as animal food, but it has rapidly invaded waterways, irrigation channels, lakes, and rice paddies.
- Under the right conditions, it can double in biomass within two weeks, forming dense mats with potentially disastrous consequences. In Africa’s Lake Victoria, water hyacinth infestations covering 12,000 hectares have blocked shipping trade and access to ports, and halted fishing activities.
Impact on Food Security: Agriculture and fisheries are particularly vulnerable to the impacts of IAS, placing food security at risk. The fall armyworm was introduced to sub-Saharan Africa, it is spreading rapidly across the continent causing yield losses of over 40% for smallholder maize farms in some countries.
Climate Change: The resilience of natural habitats can also be reduced by IAS, making them more vulnerable to the impacts of climate change. Introduced grasses and trees may alter fire regimes, particularly in areas that are becoming warmer and drier due to climate change, putting habitats and human life at risk.

Efforts to tackle Invasive Alien Species

Global initiatives

United Nations Convention on Biological Diversity: The United Nations Convention on Biological Diversity (CBD – 1992) emphasizes the need to prevent the introduction of, control, or eradicate invasive alien species that threaten ecosystems, habitats, or species.
Kunming-Montreal Global Biodiversity Framework: The Kunming-Montreal Global Biodiversity Framework (KMGBF – 2022), agreed under the UN CBD, aims to reduce the rate of introduction and establishment of invasive alien species by at least 50% by 2030.
Global Invasive Species Programme: The Global Invasive Species Programme (GISP) supports research, capacity building, and management strategies to address invasive species issues worldwide.
Invasive Species Specialist Group: The Invasive Species Specialist Group (ISSG) is a global network of scientific and policy experts on invasive species. It is organized under the auspices of the Species Survival Commission (SSC) of the International Union for Conservation of Nature (IUCN).
International Plant Protection Convention: The International Plant Protection Convention (IPPC) is an intergovernmental treaty that aims to protect the world’s plants, agricultural products, and natural resources from plant pests. One of its objectives is to mitigate the introduction and spread of invasive species.
Regional Agreements and Initiatives: Various regional agreements and initiatives, such as the European Union’s Regulation on Invasive Alien Species, address invasive species at a regional level.

Indian initiatives

Conservation Laws and Regulations: Various laws and regulations have been enhanced for the conservation of biological diversity, aiding in the management of threats posed by invasive species. Notable examples include the Biological Diversity Act of 2002, and the National Biodiversity Authority Act of 2002.
National Action Plan on Invasive Alien Species: The Ministry of Environment, Forest and Climate Change (MoEFCC) launched the National Action Plan on Invasive Alien Species (NAPINVAS). This plan focuses on the prevention, early detection, control, and management of invasive species.
National Invasive Species Information Center: The National Invasive Species Information Center (NISIC) provides information and resources on invasive species in India.
Himalayan Environmental Foundation’s Efforts: The Himalayan Environmental Foundation is actively working to control invasive species like Lantana camara in the Himalayas.
Centre for Wildlife Studies’ Research: The Centre for Wildlife Studies is conducting research on the impacts of invasive species on Indian ecosystems.

Suggestions and the way forward

Enforcement of Strict Regulations: Implement and enforce strict regulations that govern the import and transport of goods, including live plants and animals. Conduct a thorough ecological, economic, and social risk assessment associated with the species.
Biosecurity Training: Provide training to individuals working at key entry points such as ports, airports, and borders. This can be highly effective in intercepting invasive species before they enter a new environment.
Community-Involved Habitat Restoration: Involve local communities in habitat restoration and rehabilitate them by replanting native vegetation. This promotes ecosystem recovery.
Early Detection and Rapid Response: Early detection of new infestations is crucial for successful eradication. This requires proper monitoring programs, surveillance networks, and public reporting systems.
Global Collaboration Against Invasive Species: As the threats posed by invasive species transcend boundaries, sharing information, resources, and expertise across borders becomes essential to addressing this global menace.
Integrated Pest Management: This may include biological control, chemical control, and mechanical control methods. These methods are applied in a strategic and environmentally sustainable manner.

Conclusion

In conclusion, the prevention and management of Invasive Alien Species (IAS) is a multifaceted challenge that requires a comprehensive and collaborative approach. By integrating diverse strategies, conducting continuous research, raising public awareness, and fostering international cooperation, we can mitigate the damaging impacts of IAS on our ecosystems and livelihoods. The most cost-effective strategy is to prevent their introduction in the first place. A collaborative approach involving various sectors is crucial. Understanding the impacts of IAS is essential for governments, donors, and agencies to integrate prevention and management measures into projects, including those supporting the Sustainable Development Goals (SDGs).

Sources and References: Down to earth | Hindustan Times | Indian Express

Practice Question

Invasive alien species pose significant threats to biodiversity and ecosystems. Discuss the impacts of invasive alien species on India’s biodiversity and suggest measures for their management. (250 words)

How to approach this question?

Introduction (20 words):

Start by defining what invasive alien species are.
Briefly mention their global presence and their relevance to India.

Body (180 words):

Impacts:
- Discuss the impacts of invasive alien species on biodiversity. You can mention specific examples of such species in India and the threats they pose.
- Discuss the impacts on ecosystems. Explain how these species can disrupt the balance of ecosystems and lead to the extinction of native species.
Measures for Management:
- Discuss the measures that can be taken to manage and control these species. This can include preventive measures, early detection and rapid response, containment and long-term control measures.
- Discuss the role of government policies and international conventions in managing these species. Mention any specific initiatives taken by the Indian government or non-governmental organizations.

Conclusion (50 words):

Summarize the main points discussed in the body of the answer.
Emphasize the importance of managing invasive alien species to protect biodiversity and maintain the health of ecosystems.
End with a forward-looking statement, such as the need for continued research, public awareness, and international cooperation in managing invasive alien species.

Remember to provide a balanced answer, incorporating relevant facts and figures, and propose feasible solutions. Structure your answer well, with a clear introduction, body, and conclusion. Also, ensure that your answer is within the word limit specified for the exam. Good luck!

Invasive Alien Species

Introduction