Maarg Manthan · Topic 9.5

Mangroves: Definition, Distribution in India, Importance and Threats

Environment & Ecology › Coastal and Wetland Ecosystems · Topic 9.5

Mangroves are salt-tolerant trees and shrubs that grow in the intertidal zone of tropical and subtropical coasts, estuaries, creeks and deltas, where the soil is muddy, waterlogged, low in oxygen and flooded by tides. They are not one family but many unrelated plants with similar adaptations: breathing roots (pneumatophores), prop or stilt roots, salt excretion or exclusion and viviparous seedlings. Common Indian genera are Rhizophora, Avicennia, Bruguiera, Sonneratia, Ceriops and Heritiera, whose species Heritiera fomes (sundari) gives the Sundarbans their name. India's mangrove cover is about 4,900 to 5,000 sq km, or roughly 0.15 percent of the country, with West Bengal (Sundarbans), Gujarat and the Andaman and Nicobar Islands holding the largest areas; check the latest India State of Forest Report. Mangroves protect coasts, store blue carbon, shelter fish nurseries and support fisheries, but are lost to aquaculture, reclamation, pollution and reduced freshwater flow.

5 min read · UPSC Prelims · Environment & Ecology · Coastal and Wetland Ecosystems

At a Glance

Zone Intertidal, tropical coasts
Indian cover About 4,900 to 5,000 sq km
Largest area West Bengal (Sundarbans)
Key roots Pneumatophores, stilt roots
Day 26 July
Exam link UPSC Prelims, Environment & Ecology: Coastal and Wetland Ecosystems

Where Does It Fit?

This topic follows the account of estuaries and their adaptations. Mangroves are the signature plant community of tidal coasts and the first line of defence against cyclones, so they lead the study of coastal ecosystems into law, community action, corals and wetlands. Previous topic: Estuarine Ecosystem Adaptations and Conservation. Next topic: Environment (Protection) Act, 1986 Key rule CRZ Notification CRZ category CRZ-I for mangroves Buffer 50 m for…">Legal and Regulatory Approaches for Mangrove Protection.

Where Do Mangroves Grow in India and What Are the Main Types?

Region	Mangrove features
Sundarbans (West Bengal)	Largest mangrove forest in the world, shared with Bangladesh; Heritiera fomes, Avicennia and Excoecaria; Bengal tiger; UNESCO World Heritage Site
Bhitarkanika (Odisha)	Second largest mangrove area in India; saltwater crocodile, Olive ridley nesting at Gahirmatha nearby; Ramsar site
Gujarat	Large cover in the Gulf of Kutch and Gulf of Khambhat, mostly Avicennia marina
Andaman and Nicobar Islands	Rich, diverse mangroves, with many Rhizophora species
Godavari and Krishna deltas (Andhra Pradesh)	Coringa and Krishna wildlife sanctuary mangroves
Tamil Nadu	Pichavaram and Muthupet on the Kaveri delta
Maharashtra, Goa, Karnataka and Kerala	Smaller patches along creeks and estuaries such as Thane Creek and the Mandovi

Why Are Mangroves Important and What Threatens Them?

Coastal protection: roots break waves and reduce cyclone and tsunami damage
Blue carbon: mangrove mud stores carbon for centuries
Nurseries: fish, prawns and crabs breed among the roots
Livelihoods: fish, honey, wood, fodder and tourism for coastal communities
Sediment trapping: roots hold mud and build land
Biodiversity: tigers, crocodiles, birds, fishing cats and many invertebrates
Aquaculture: shrimp ponds replace mangroves
Reclamation and pollution: ports, housing, oil, plastics and sewage degrade stands

What Else Should You Remember?

Pneumatophores: upward breathing roots of Avicennia that rise above the mud for gas exchange
Prop roots: arching roots of Rhizophora that anchor trees in soft mud
Stilt roots: similar support roots that raise the trunk above the water
Knee roots: bent roots of Bruguiera that rise from the mud
Viviparous seedlings: seeds germinate on the parent tree, then drop as propagules
Salt excretion: Avicennia leaves secrete salt through glands
Salt exclusion: Rhizophora roots filter out most salt
Zonation: Avicennia and Sonneratia grow on the seaward side, Rhizophora in the middle and Bruguiera and Heritiera on higher ground
Sundari tree: Heritiera fomes, a hardwood that gives the Sundarbans their name
Mangrove cover trend: national cover has risen slightly in recent India State of Forest Reports, but quality and species mix differ
ISFR: India State of Forest Report, issued by the Forest Survey of India every two years
Mangrove Day: 26 July is the International Day for the Conservation of the Mangrove Ecosystem
Blue carbon: carbon stored in coastal and marine ecosystems including mangroves, seagrass and salt marsh
Tsunami 2004: areas with dense mangroves suffered less damage in several studies
Cyclones: mangroves in the Sundarbans reduce the impact of storm surges
Fishing cat: a threatened wetland cat found in mangroves of West Bengal and Odisha
Saltwater crocodile: the largest living reptile, found in Bhitarkanika and the Sundarbans
Sea level rise: mangroves need space and sediment to move landward as seas rise
Salinity change: reduced river flow raises salinity and stunts growth
Shrimp culture: a major cause of mangrove clearance in Andhra Pradesh and elsewhere
Tourism pressure: unregulated boat traffic disturbs wildlife
Link to previous: see Estuarine Ecosystem Adaptations and Conservation
Link to next: see Legal and Regulatory Approaches for Mangrove Protection
Link to corals: see atoll India Mannar, Kutch,…">Coral Reefs: Formation, Geographical Conditions, Types
Caution: area figures change with each forest report and with the method used, so quote them as approximate
Exam hint: learn the state ranking, root types and the Sundarbans and Bhitarkanika facts

Why Does It Matter for the Exam?

Largest cover: West Bengal
Root types: Pneumatophore, prop, stilt
Key sites: Sundarbans, Bhitarkanika
Current affairs link: MISHTI and Mangrove Day
Common errors: calling mangroves a single species or placing Pichavaram in Odisha

As an analytical point, mangroves give cheap and self-repairing defence against storms, carbon and fisheries, yet they sit on land that developers and shrimp farmers want. Counting their value in disasters avoided and livelihoods supported helps decide against clearing.

Why Is This Topic Important?

Defence Storm buffer
Climate Blue carbon
Life Nursery

What Came Next?

The next topic covers the legal and regulatory approaches that protect mangroves. Next topic: Legal and Regulatory Approaches for Mangrove Protection.

Key People and Terms

Mangrove Salt-tolerant intertidal forest
Pneumatophore Breathing root
Propagule Germinated seedling
Blue carbon Carbon in coastal ecosystems
Intertidal Between high and low tide
Sundari Heritiera fomes

Exam Corner

Points to Remember

Largest cover: West Bengal.
Cover about 0.15 percent of India.
Day: 26 July.
Roots: pneumatophores, prop, stilt.
Reports by FSI every two years.

Do Not Confuse With

Mangrove and mangrove species Habitat type versus plant names
Sundarbans and Bhitarkanika Largest versus second largest
Pneumatophore and prop root Breathing versus anchoring

Memory Hook

Salt, mud and tide, roots breathe and brace, Bengal leads, tigers hide.

Mains Angle

Questions ask for states, species and importance. These points help.

Value Storm, carbon
Threat Shrimp, filling
Way Restore, protect

A Question You May Face

An original practice question, not a past paper question.

“Discuss the distribution of mangroves in India and their ecological and economic importance. What are the threats they face?”

How to Answer

Define Intertidal.
Spread States.
Value Defence, carbon.
Way Law, community.

GS Relevance

Prelims: adaptations, distribution, states, species. GS Paper 3: coastal ecosystems, climate and disaster protection.

Frequently Asked Questions

What are mangroves?

Mangroves are salt-tolerant trees and shrubs that grow in the intertidal zone of tropical and subtropical coasts, estuaries and deltas. They survive in muddy, waterlogged, salty soil through special roots, salt-handling leaves and seedlings that germinate on the tree. They form a unique coastal forest that links land and sea.

Which Indian state has the largest mangrove cover?

West Bengal has the largest mangrove cover in India because of the Sundarbans, followed in recent reports by Gujarat and the Andaman and Nicobar Islands. The exact ranking and area change with each India State of Forest Report, so the latest edition should be checked for current figures.

What are pneumatophores?

Pneumatophores are upward-growing breathing roots of mangroves such as Avicennia that rise above the waterlogged mud and have small pores to take in air. They help the plant get oxygen in soil that is low in oxygen. Other mangroves, like Rhizophora, have prop or stilt roots for support.

How do mangroves protect the coast?

Mangrove roots and trunks slow down waves, currents and storm surges, trap sediment and bind soil, which reduces erosion and flood damage during cyclones and tsunamis. Dense mangrove belts have been shown to reduce wave energy, and they also protect the fish nurseries and villages behind them.

What is blue carbon?

Blue carbon is the carbon captured and stored by coastal and marine ecosystems such as mangroves, seagrass meadows and salt marshes. Much of it is held in waterlogged soil for centuries, so protecting these habitats keeps carbon out of the air, while destroying them releases it as greenhouse gas.

PYQ Practice — Statement Analysis

1 Mangroves grow in the intertidal zone.

True

Between high and low tide.

2 Pneumatophores are breathing roots.

True

They rise above mud.

3 Gujarat has the largest mangrove cover in India.

False

West Bengal leads.

4 Mangroves are a single plant species.