Samoa: Respecting the Mangroves

Case Study: The Mighty Mangrove:

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1. Birdlife/Nesting

The mangrove provides feeding and roosting grounds for many bird species that prefer or need a coastal habitat.

2. Leaves

Each leaf is a tiny solar panel, dark on top to soak up the sun's energy and convert it to chemical energy (photosynthesis). With no canopy of trees to protect its leaves, the upper surface has evolved to be hard, leathery and shiny to conserve water.

3. Food web

Mangroves are one of the starting points in the great chain of marine and seashore life. Decaying leaves and animal wastes produce nutrients that sustain a mass of algae and plankton. These are then eaten by crabs, eels and fish. Birds and larger fish eat smaller fish and so the food web extends.

4. Shelter/Nursery

The mangrove forest provides a nurturing place for plankton, algae, snails, shellfish and bottom dwelling creatures and is a necessary nursery area for young fish, including commercially important species.

5. Mangrove Litter

Mangroves are one of the world's most productive vegetation types. Each year they shed millions of leaves - approximately ten tonnes per hectare! The rotting leaves form a nutrient compost - a valuable food source for many organisms.

6. Roots

The mud that surrounds the mangrove tree lacks oxygen. As all trees need air, the mangrove has evolved spongy roots that stick up from the mud and breathe for the plant.

7. Shoreline Protection

Mangroves form an underground network of roots that hold the earth together and prevent it from being washed away. Above the ground the roots act like a comb and trap bits of earth and sediment; in these ways mangroves build up and extend shorelines.

Mangrove seedlings grow in the newly formed ground and the mangrove front advances towards the sea.

8. Renewable resources.

Mangroves are used to provide dyes, or colouring material, and wood for cooking and building. They can continue to be used this way forever, as long as the quantity of mangroves cut down is no more than that which can be replaced by natural growth.

9. Food for people

Many important food species use the mangroves for at least part of their life-cycle;

• permanent home for some species such as oysters and mud crabs
• nursery areas for animals such as prawns and mangrove mullet
• feeding areas for the black spot sea perch, which visits to feed

10. Storm Protection

Mangroves are the first line of defence against storm surges and cyclones. The closely formed root systems help to break strong wave action. The densely formed trees act as a wind break against hurricane force winds.

Next: 5 Ways to Protect Mangroves