Wetlands, Mangroves, Coral Reefs and Coastal Ecosystems of India Notes for UPSC: Ramsar Sites, Sundarbans, Gulf of Mannar, CRZ Rules, Threats and Conservation

India's long coastline, big rivers and monsoon rains have given it a rich variety of wetlands, mangroves, coral reefs, lagoons and estuaries. These coastal and wetland ecosystems protect the shore from storms, filter the water, store carbon, support the fisheries and give a home to a large number of species and migratory birds. For UPSC, they are a high-yield topic: the Prelims asks about the Ramsar sites, the mangrove forests, the coral reef areas and the protected marine parks, and the Mains asks about the threats, the Coastal Regulation Zone (CRZ) rules and the conservation methods. These notes cover the definitions, the distribution, the importance, the threats, the laws and the Indian examples of each ecosystem, with simple tables and memory tricks.

Why This Topic Matters for UPSC

These ecosystems link the Geography (the coastline and the rivers), the Environment (biodiversity, climate change) and the Disaster Management (cyclones, tsunamis and the sea-level rise). They are also often in the news, for example, new Ramsar sites, mangrove restoration under the MISHTI scheme, the coral bleaching and the CRZ amendments. Revise it with our notes on Protected Areas, Ramsar Sites and Wildlife Laws, Biodiversity and Conservation and Indian Coastal Plains, Islands and Lakes.

Wetlands

The Ramsar Convention defines wetlands as areas of marsh, fen, peatland or water, natural or artificial, permanent or temporary, with water that is static or flowing, fresh, brackish or salt, including the areas of the marine water, the depth of which at low tide does not exceed six metres. They include the lakes, the rivers, the flood plains, the mangroves, the coral reefs, the paddy fields and the reservoirs. Wetlands are called the "kidneys of the landscape", as they filter the water, recharge the groundwater and reduce the floods.

India has a large and growing number of Ramsar sites (more than 80 now, among the highest in Asia). The Wetlands (Conservation and Management) Rules, 2017 regulate the wetlands, and the National Plan for Conservation of Aquatic Ecosystems supports the conservation. The Montreux Record lists the sites where the ecological change has occurred or may occur; Keoladeo and Loktak have been in the Record. World Wetlands Day is observed on 2 February.

Mangroves

Mangroves are salt-tolerant trees and shrubs found in the intertidal zones of the tropical and subtropical coasts, where the rivers meet the sea. They have special adaptations: the stilt roots for support, the pneumatophores (breathing roots) that rise above the mud for the oxygen, the salt-excreting leaves and the viviparous germination, where the seed sprouts while still on the tree.

• Distribution in India: The Sundarbans in West Bengal is the largest mangrove area, followed by Gujarat and the Andaman and Nicobar Islands. Other important areas are Bhitarkanika (Odisha), the Godavari-Krishna delta (Andhra Pradesh), the Pichavaram (Tamil Nadu) and the Maharashtra and Kerala coasts. India's mangrove cover is nearly 5,000 sq km, as reported in the India State of Forest Report.
• Importance: Natural barrier against the cyclones and the tsunami, the nursery for the fish and the prawns, the carbon storage (the "blue carbon"), the stabilisation of the shoreline and the livelihood of the coastal communities.
• Threats: The conversion into the aquaculture (shrimp farming), the port and the real estate development, the pollution, the reduced freshwater flow due to the dams and the sea-level rise.
• Initiatives: The MISHTI (Mangrove Initiative for Shoreline Habitats and Tangible Incomes, 2023) scheme for the mangrove plantation, the CRZ rules that protect the mangroves, and the Global Mangrove Alliance of which India is a part.

Coral Reefs

Coral reefs are formed by the tiny animals called coral polyps, which secrete the calcium carbonate skeletons, and live in a symbiotic relationship with the algae called zooxanthellae that give them colour and food. They grow in the clear, shallow, warm waters (about 23 to 29 degrees Celsius) of the tropical oceans, and are called the "rainforests of the sea" for their biodiversity.

The threats include the coral bleaching (the loss of the algae because of the rising sea temperature, which turns the coral white), the ocean acidification, the pollution, the destructive fishing and the sedimentation. Corals are protected under Schedule I of the Wildlife (Protection) Act, 1972 and by the CRZ rules.

Estuaries, Lagoons, Salt Marshes and Seagrass

• Estuaries are the partly enclosed coastal water bodies where the river meets the sea, as at the Narmada and the Tapi on the west coast. They are rich in nutrients and are the nursery of the fish.
• Lagoons are the shallow waters separated from the sea by a sand bar: Chilika, Pulicat and the backwaters of Kerala.
• Seagrass meadows are underwater flowering plants found in the Gulf of Mannar and Palk Bay, which feed the dugong (the sea cow), and store the carbon. The dugong conservation reserve is in the Palk Bay.
• Salt marshes and mudflats support the migratory waders.

Laws and Policies for the Coastal and Wetland Ecosystems

Threats Common to the Coastal and Wetland Systems

• Encroachment, land reclamation and the conversion for the agriculture, the aquaculture and the real estate.
• Pollution from the sewage, the industries, the plastic and the oil spills.
• Climate change: the sea-level rise, the warming of the seas, the more intense cyclones and the changes in the river flows.
• Over-exploitation of the fish and the destructive methods of fishing.
• Invasive species such as the water hyacinth that choke the wetlands.

The Mains Angle: Conservation and Livelihood

For the Mains, show that these ecosystems provide both the ecological services (the storm protection, the carbon storage, the water filtration) and the livelihoods (the fishing, the tourism and the salt). The way forward includes the strict implementation of the CRZ and the wetland rules, the restoration of the mangroves and the corals with the community participation, the control of the pollution, the sustainable fishing, the use of the satellite mapping for the monitoring, and the integration of the ecosystem protection in the disaster and the climate plans, as the "nature-based solutions". Examples such as the Odisha cyclone protection by the mangroves and the community-managed Sundarbans work can strengthen the answer.

Previous-Year Style Practice

• Which is the largest mangrove forest in the world? Answer: The Sundarbans.
• Where is the Gulf of Mannar Biosphere Reserve? Answer: Tamil Nadu.
• What is coral bleaching? Answer: The loss of the zooxanthellae algae from the coral due to the stress, mainly the warm water.
• Which is the first Marine National Park of India? Answer: The Marine National Park in the Gulf of Kutch, Gujarat.

Frequently Asked Questions (FAQ)

Which is the largest brackish water lagoon in India?

Chilika Lake in Odisha.

Which is the largest mangrove forest in the world?

The Sundarbans in West Bengal and Bangladesh.

What are pneumatophores?

The breathing roots of the mangroves that rise above the mud to take oxygen.

What is the Ramsar Convention?

An international treaty (1971) for the conservation and the wise use of the wetlands.

What is the Montreux Record?

A list of the Ramsar sites where the ecological character has changed or is likely to change.

Which day is World Wetlands Day?

2 February.

What causes coral bleaching?

The loss of the symbiotic algae (zooxanthellae) due to the rising temperature or the stress.

Where are the coral reefs found in India?

In the Gulf of Mannar, the Gulf of Kutch, Lakshadweep and the Andaman and Nicobar Islands.

What is the CRZ?

The Coastal Regulation Zone, in which the activities within 500 m of the high tide line are regulated.

What is MISHTI?

The Mangrove Initiative for Shoreline Habitats and Tangible Incomes, a scheme launched in 2023.

What is blue carbon?

The carbon stored in the coastal and marine ecosystems such as the mangroves, the seagrass and the salt marshes.

How is the topic asked in UPSC?

As the Ramsar sites, the mangrove and the coral regions, the laws and the conservation measures.