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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