MANGROVE FOREST

OBJECTIVES

• Describe the distribution of mangroves. • Describe climatic features of MG areas.

• Describe & explain the features of MG.

• Describe the adaptations of MG.

DISTRIBUTION

• along sheltered coastal regions

• Found b/w 23.5°N and S of the equator.

• areas experiencing tropical climate

STRUCTURE

• 3 distinct horizontal zones

• No vertical layers

Horizontal zonation of Mangroves

• http://www.mesa.edu.au/mangroves/images/mang_zones.jpg

STRUCTURE

• Coastal Zone– Nearest to the coast– Adapted to salt water– Aerial roots– Avicennia, Sonneratia

• Inland Zone– Grow inland– Least tolerant of salt– Knee-like roots– Bruguiera

• Middle Zone– Prop roots – Stilt roots– Rhizophora

CHARACTERISTICS

C1: Little Variety

• Mangrove is species poor as there are only 4 main species present: Avicennia, Sonneratia, Rhizophora, Bruguiera

• This is because only Halophytes (salt tolerant plants) can survive in this region.

C2: Dense & Luxuriant

• Most form a dense, continuous canopy due to the presence of high temperatures and high rainfall.

C3: Sparse Undergrowth

• Little sunlight filters through the dense, continuous canopy.

• Hence there is little undergrowth

present in this layer.

C4: Evergreen leaves

• As there is high temperature and high rainfall throughout the year, the leaves remain evergreen.

C5: Colourful flowers

• The flowers are generally colourful to attract insects to pollinate its flowers.

C6: Buoyant Fruits

• This enables fruits to be carried away by waves and currents to new coastal areas.

ADAPTATIONS

A1: High rainfall

• The leaves are broad with drip tips to enable water to flow off the leaves quickly.

A2: High Temperature

• The leaves are thick and leathery to reduce water loss through transpiration.

A3: Salt

• Avicennia are salt secretors: They excrete excess salt on their leaves which are then removed by the wind or rain.

• Bruguiera, Rhizophora, Sonneratia are ultrafiltrators: They absorb salt and store it in the old leaves which fall off eventually.

A4: Oxygen Deprived

• Due to waterlogged conditions in the mangrove environment, the soil is oxygen-deprived.

• Avicennia and Sonneratia have aerial roots: As these roots are exposed during low tide, they take in oxygen.

A5: Muddy Soil• Prop Roots

– Rhizophora: Stilt or prop roots which anchor the roots firmly to the ground

• Keed Roots (Knee-Like)– Bruguiera: Kneed roots that provide firm

support on the soft soil.

• Fruits with elongated structure: – Rhizophora: enables the fruits to anchor in soft

muddy soil.

PENCIL ROOTS

PROP ROOTS

KNEED ROOTS

BUOYANT FRUITS

THE END