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 Inland Zone Middle 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 Keed Roots (Knee-Like) 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