Invasive plant Species in India: Threats to Biodiversity and Ecosystem Health

Imagine a tranquil swamp or forest that is abruptly overtaken by ruthless invaders. As more invasive species invade India’s different ecosystems, this is the fact that the country must deal with. Often going unseen, these “green bullies” quickly overtake native plants and animals by spreading like wildfire. The harm is rapid and extensive, ranging from the water-hogging Lantana camara ( wild sage) that suffocates local plants to the aggressive Prosopis juliflora (Vilayati Babul) that has transformed huge desert regions into a desolate wilderness.Eichhornia crassipes (water hyacinth) is an environmental hazard that clogs lakes and rivers, stifling aquatic life and upsetting fishing-dependent local economies. Due to its allergenic qualities, even the apparently innocuous Parthenium hysterophorus (Congress grass) has taken over roadsides and fields, posing health risks to both people and animals.

What Are Invasive Species?

Plants, animals, or microorganisms that are purposefully or inadvertently brought to a new area and endanger the environment, the economy, or public health are known as invasive species. These species can proliferate quickly and spread far because they frequently lack natural competitors or predators in their new habitat. By changing ecosystem processes like nutrient cycling, fire regimes, and water availability, invasive species can either directly or indirectly outcompete native species for resources like food, space, and light.
Even though not all non-native species develop into invasive ones, those that do frequently have significant and occasionally permanent impacts on ecosystems. One of the biggest threats to biodiversity in the world today is the spread of invasive species, and this is also true in India.

Major Invasive Species in India:

Numerous species find homes in India’s diverse environments if we are talking about it in numbers India has 173 invasive alien species out of which 58 species are terrestrial plants and 8 species are aquatic plants, these species range from the tropical rain forests in the south to the Himalayas in the north. However, many of these ecosystems have been disturbed by the introduction of these non-native species, whether for commercial, agricultural, or ornamental interests. An extensive examination of some of India’s most harmful invasive species can be found here.

1. Lantana (Lantana camara)

Lantana camara’s name comes from the Latin “lento,” which means to bend. Linnaeus was the first to describe the species and give it its binomial name in 1753. It is a genus in the Verbenaceae family, and there are 600 variations worldwide. Lantana camara, a native plant of South, Central America, and the Caribbean islands, has been found in Brazil, Florida, Jamaica, Mexico, and Trinidad. It is also thought that some Lantana camara species are native to Africa, while another is native to India.

Imapcts and problems :
In many regions of India where it has been introduced, Lantana camara is regarded as a nuisance weed. The species creates dense thickets and tends to supplant native species, which either lowers productivity or makes harvesting on plantations more difficult. Additionally, certain species may pollute the rarely seen plant species’ gene pool.
Instead of hybridisation, competition poses the greatest threat. In the presence of light, soil moisture, and soil nutrients, it is a very efficient competitor against native colonisers. One of the most noticeable changes that occur with the replacement of forest understory is a fall in community biomass.
A recent study discovered that Lantana camara, a tropical American shrub, had invaded more than 40% of India’s tiger area. The Shivalik hills, Central India, and the Southern Western Ghats are the hardest hit. Lantana is able to adapt to different climates and can withstand high temperatures and dampness.
Its occurrence on forest borders is viewed as a severe hazard to the community due to greater fire incursions into the forest. This is especially true when the species lives along the edges of forest paths and creeks in natural forests like national parks. Lantana camara is a major issue in agricultural areas across India, causing extensive thickets, outcompeting pasture plants, and harming both flora and fauna.

Control Measures:
Despite different control techniques, Lantana camara infestations in India have not been totally eliminated
Manual Clearing: Physical removal is one of the most popular control measures; it is time consuming and frequently requires repeated efforts.
Biological Control: Although they have had limited effectiveness, biocontrol agents such as the Lantana beetle (Acanthoscelides puncticollis) have been introduced in some areas.
Chemical herbicides have been utilised in some places, however there are questions about the long-term ecological effects of this strategy.

2. Water Hyacinth (Eichhornia crassipes)

The Amazon basin is home to the enormous aquatic plant known as water hyacinth (Eichhornia crassipes). On modified stems that can reach up to one metre above the water’s surface, its thick, oval-shaped, waxy leaves, branch out from the centre of the plant. . The plant is kept afloat by the air-filled tissues found in the petioles, which are spongy, bulbous stalks. Since its introduction to India in 1896, it has spread throughout the nation, posing a threat to the environment and society in freshwater lakes, irrigation channels, communal ponds, rivers, and the majority of other surface waterbodies. Because of its potential for growth and significant socioeconomic effects, the International Union for Conservation of Nature (IUCN) named water hyacinth as one of the most harmful invasive species in the world.
Impacts and problems: Water hyacinth is distinguished by its capacity for reproduction, quick spread, and rapid development because it can lead to the following significant environmental and socioeconomic issues: (i) a drop in the concentration of dissolved oxygen in open waters, especially during non-photo periods, which results in anoxic states and a decrease in fish populations; (ii) damage to fishing boats and other inland water transportation, including increased fuel consumption, boat repairs, and a shorter boat lifespan; (iii) delays in transportation due to obstructions in canals, rivers, and small channels; (iv) diminished water flow and damage/loss of power to hydroelectric power stations, as w (vi) a rise in disease-carrying insects like mosquitoes drawn to the areas.

Control Measures:
To stop the spread of water hyacinth, several tactics have been used. Large areas of the plant are commonly removed mechanically, usually with the help of dredgers or boats. However, because of the plant’s quick regrowth, this procedure is time-consuming and frequently ineffectual over time. A different strategy is biological control, which involves introducing natural enemies, such as the weevil Neochetina eichhorniae, to eat the plant and slow its growth. Herbicides have also been used for chemical control, however this raises questions regarding possible harm to the aquatic habitat. The most effective strategy has been an integrated one that combines chemical, biological, and mechanical treatments with educating the public about the ecological risks that water hyacinth poses.

3. Vilayati babul (Prosopis juliflora)

The very invasive tree species Prosopis juliflora, also referred to as mesquite or Vilayati Babul, has become a major environmental and economic issue in India. Originally from Central and South America, it was brought to India in the 1800s for a number of uses, including feed, soil stabilisation, and afforestation. It has, however, quickly expanded throughout India’s dry and semi-arid regions, such as Rajasthan, Gujarat, Tamil Nadu, and portions of Uttar Pradesh, where it has established itself as a dominant species. There, it frequently displaces native flora and causes a host of ecological problems.
Prosopis juliflora is a robust, drought-tolerant tree that thrives in arid, salty, and water-stressed soils. Its deep taproot allows it to obtain groundwater and survive in locations with low rainfall. The tree produces enormous, hard seeds, which are transported by animals and wind, resulting in rapid spread.

Impacts and problems:
Prosopis juliflora has serious ecological implications in India. It fiercely competes with natural plant species, limiting the availability of food for grazing animals and endangering agricultural lands. Traditional agricultural techniques are interrupted in areas where this tree is invasive, and land productivity suffers as a result of its capacity to change soil structure, increase salinity, and deplete groundwater supplies. Furthermore, its dense growth obstructs wildlife migration and lowers accessible grazing space for animals. The presence of Prosopis juliflora in large numbers also leads to ecosystem deterioration, including soil erosion, lower water retention, and a loss of biodiversity.
Control measures:
Prosopis juliflora has been controlled using a variety of approaches. Mechanical control entails cutting, uprooting, and removing trees, which is labour-intensive and only provides short relief until the entire root structure is destroyed. Herbicide application is another option, albeit its use raises issues about environmental safety and the possibility of injuring non-target species. Biological control is also being investigated, with studies looking into introducing herbivores or insects that feed on the plant to curb its spread. Furthermore, afforestation and reforestation efforts focused at planting native species are being implemented to repair ecosystems disrupted by Prosopis juliflora.

4. Congress grass ( Parthenium hysterophorus)

One of the most invasive plant species in India and other countries is Parthenium hysterophorus, also referred to as Congress grass or whiteweed. Originally from the Americas, it was unintentionally brought to India in the 1950s, most likely as a contaminant in crop seeds or tainted agricultural products. Since then, the plant has quickly expanded throughout a large portion of the nation, flourishing in a variety of settings such as disturbed lands, agricultural fields, and roadside areas. The herbaceous annual parthenium grows quickly and can grow up to two meters in height. It features clusters of tiny white flowers, fragrant foliage, and heavily branching branches.

Impacts and problems :
Parthenium hysterophorus has catastrophic and far-reaching effects. Its impact on both human and animal health is among the biggest worries. Sesquiterpene lactones, among other harmful compounds produced by the plant, are responsible for severe allergic reactions, skin rashes, asthma, and other respiratory disorders in people. Because parthenium is poisonous to many animals, it also affects livestock that graze on it, which can result in decreased livestock productivity or, in severe situations, poisoning. Parthenium outcompetes native plant groups for light, nutrients, and space, upsetting their ecological balance. Because it can totally displace natural flora and create monocultures that are inappropriate for many local wildlife species, this leads to a reduction in biodiversity.
Control measures:
Many strategies have been used to slow the spread of Parthenium, but total eradication is still difficult. One of the most popular techniques is mechanical control, which involves physically uprooting or pruning the plants, although it takes constant work and isn’t always successful in huge infestations. Herbicides are occasionally used to control plants, but if not used properly, they can be expensive and environmentally damaging. Research on introducing natural predators, including insects that eat Parthenium, to help stop its spread has showed some promise in biological management.
Furthermore, Parthenium is kept from spreading to new locations by encouraging the use of local vegetation in afforestation and reforestation initiatives. Campaigns to raise public awareness are essential for motivating people to recognise and care for the plant, especially in rural and agricultural areas.

In India, a number of organisations are actively engaged in the detection, control, and management of invasive species. The goals of these initiatives are to protect biodiversity, rebuild ecosystems, and advance environmentally friendly and sustainable farming methods. Several important groups working to combat invasive species in India include

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Government Organizations:

  • National Biodiversity Authority (NBA):The NBA plays a crucial role in developing and implementing strategies for invasive species management. They collaborate with various stakeholders to create awareness, conduct research, and promote sustainable practices.
  • Botanical Survey of India (BSI):The BSI is responsible for identifying and monitoring invasive plant species. They conduct surveys, collect data, and publish research findings to inform management strategies.
  • Forest Departments:State forest departments play a vital role in controlling invasive plants within forest areas. They undertake eradication programs, create awareness campaigns, and collaborate with local communities.

Non-Governmental Organizations (NGOs):

  • Wildlife Trust of India (WTI):The WTI focuses on conservation efforts, including the management of invasive species. They work with local communities to implement control measures and promote sustainable practices.
  • Bombay Natural History Society (BNHS):The BNHS conducts research on invasive plants, their impact on ecosystems, and effective control methods. They collaborate with government agencies and other NGOs to implement conservation programs.
  • Ashoka Trust for Research in Ecology and the Environment (ATREE):ATREE works on various environmental issues, including invasive species management. They conduct research, develop control strategies, and collaborate with local communities to implement sustainable solutions.

International Organizations:

  • International Union for Conservation of Nature (IUCN):The IUCN provides global leadership on nature conservation and sustainable development. They support research, policy development, and capacity building to address invasive species issues worldwide.
  • Convention on Biological Diversity (CBD):The CBD promotes the conservation of biological diversity, sustainable use of its components, and fair and equitable sharing of the benefits arising from the utilization of genetic resources. They address invasive species as a major threat to biodiversity.

Local Communities:

Local communities play a vital role in the management of invasive plants. They can participate in eradication efforts, adopt sustainable practices, and spread awareness about the harmful effects of invasive species.
These organizations, along with government agencies and local communities, are working together to combat the threat of invasive plants in India. Their efforts contribute to the conservation of biodiversity and the protection of ecosystems.

A Technological Edge in the Battle Against Invasive Plants

Technology has become a powerful ally in the fight against invasive plant species, by utilizing advanced tools and techniques, we can more effectively identify, track, and control these harmful intruders.

Advanced tools and techniques:

Remote Sensing, Geographic Information Systems (GIS),Drone Technology, Artificial Intelligence and Machine Learning
Satellite imagery and aerial photography allow us to spot and map invasive plant infestations across vast areas. GIS helps us monitor the spread of these plants over time and predict future patterns. Drones equipped with sprayers can precisely target invasive plants with herbicides, minimizing environmental impact. These aerial vehicles can access remote and difficult-to-reach areas, making it easier to treat infestations in challenging terrains. Additionally, drones can capture high-resolution images and videos to monitor the effectiveness of control measures.
AI-powered image analysis can automatically identify and classify invasive plant species, even in complex environments, Machine learning algorithms can analyze historical data and environmental factors to predict the future spread of these plants. This information can help us develop optimized control strategies and allocate resources efficiently.

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Citizen Science and Mobile Apps

Citizen science initiatives empower the public to play an active role in monitoring and reporting invasive plant sightings. User-friendly mobile apps provide information about invasive plant identification, distribution, and control methods. By sharing data collected through citizen science, we can supplement scientific research and inform management decisions.

Overcoming Challenges and Future Directions

While technology offers significant potential, challenges such as cost and data quality must be addressed. To fully harness the power of technology, we need to foster collaboration between scientists, policymakers, and stakeholders. Continued investment in research is crucial to develop innovative technologies and deepen our understanding of invasive plant ecology. Additionally, promoting education and awareness can encourage responsible gardening practices and public participation in control efforts.
By combining technological advancements with collaborative efforts, we can effectively combat the threat of invasive plant species and protect our environment for future generations.

Written by Shaik Shaheen, Naturalist at Pugdundee Safaris

About the Author: She majored in Master’s in wildlife conservation from Pune in 2021. Having lived in the city her entire life, she would always find her escape in the outskirts of the city of Hyderabad, and she was effortlessly drawn towards wildlife as a career. While she was pursuing her bachelor’s in Genetics and Microbiology, she worked at Hyderabad zoo as a volunteer on the weekends.

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