Mangroves

Chapter 2

Mangrove Forests

In this lesson, you will understand:

• Where are Mangrove Forests found?• What general characteristics do MF have?• What special adaptations do MF have?

Distribution of Mangrove Forests

• Places that experience tropical climate i.e. between 23.5ºN & S of Equator

• especially along sheltered coastal regions and where rivers deposit clay and silt

Diversity of Mangrove Forests

• Halophytes (salt-tolerant plants) commonly found– e.g. avicennia, sonneratia, rhizophora, bruguiera– other plant species e.g. sea hibiscus, nipah palm

Density of Mangrove Forests

• High density due to high temperature & rainfall• Sparse undergrowth due to dense canopy

Structure of Mangrove Forests

• 3 horizontal zones with trees about 15m tall• Trees vary in height from 2m – 40m as muddy soil

in environment cannot provide firm support

High tideLow tide

Coastal zoneCoastal zone Middle zoneMiddle zone Inland zoneInland zone

Coastal Zone in Mangrove Forests

• Nearest to sea, flooded with saltwater at high tides• Trees have tube-like breathing roots • e.g. avicennia species (pencil shaped)• e.g. sonneratia species (peg shaped)

Middle Zone in Mangrove Forests

• Trees have prop or stilt roots growing from trunks for anchoring plants firm to muddy soil

• e.g. rhizophora species

Inland Zone in Mangrove Forests

• Trees have knee-like roots to provide support on soft soil

• e.g. bruguiera species that are least salt-tolerant

MF Special Characteristics: Leaves

• Evergreen, thick & leathery, broad with drip tips

• Avicennia species are salt secretors– excess salt secreted on leaves

and removed by wind or rain• Bruguiera, Rhizophora and

Sonneratia species are ultrafiltrators– excess salt stored in old leaves

which then fall off

MF Special Characteristics: Flowers and Fruits

• Generally colourful flowers to attract insects for pollination– e.g. Bruguiera species has

bright-red lantern flowers• Buoyant fruits that are

dispersed by water• Elongated fruits which

germinate while on parent tree– e.g. Rhizophora species

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In this lesson, you have understood:

• Where are Mangrove Forests found?• What general characteristics do MF have?• What special adaptations do MF have?