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COASTAL ECOSYSTEMS
MANGROVES
BIOL 202 MARINE BOTANY
FALL 2009
What are Mangroves?
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Mangue (Portuguese)---?
Grove----?
Woody trees or shrubs found at the
sea/land interface in tropical estuaries.
3 types: 1) Riverine; 2) Tide-dominated;
and 3) Basin Mangroves
MANGROVE WETLANDS
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Mostly dicots—Myrtales
and Rhizophorales
(representing about 50%
of the species)
Families: Avicenniaceae,
Rhizophoraceae,
Combretaceae,
Sonneratiaceae.
Palmae- One monocot
Nypa fruticans
SPECIES OF MANGROVES-60
species worldwide
Black Mangrove
Red Mangrove
Viviparous
propagule
Sweet Mangrove
White Mangrove
ORIGIN OF MANGROVES
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Indo-Malayan region.
Spread westward by
ocean currents during
the Late Cretaceous
and Lower Miocene.
Seeds and propagules.
Characteristics of Mangroves
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Evergreen plants with thick
leathery leaves designed to
minimize transpiration.
Viviparous germination where the
seed germinates on the tree and
falls down in the germinating
condition with a long radiclecharacteristic of Rhizophoraceae .
Root system has many unique
types of roots. 1. Stilt-roots, 2.
Pneumatophores, 3. Root knees.
4. Plank Roots
ROOTS
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STILT ROOTS--looping roots
arise from the trunk and lower
branches
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PNEUMATOPHORES-Erect
roots that are extensions of the
underground root system. These
roots are exposed at least part
of the day and not submerged
underwater, the root system can
obtain oxygen in an otherwise
anaerobic substrate.
ROOTS
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KNEED ROOTSthe horizontal roots
growing vertically upwards
and forming loops
downwards to resemble a
bent knee.
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PLANK ROOTSwavy, snake-like roots that
radiate outwards from the
trunk base.
Lenticels
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Lenticels—small
pores present on
aerial roots.
Lenticels are
susceptible to
clogging by crude oil
and other
pollutants, and
attacks by parasites.
Do Mangroves need salt?
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Facultative
halophytes
Grow in fresh water
+ salt water.
COPING WITH SALT
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Exclude Salt (no
intake)
Extrude salt (take
salt in and dispense
it through glands in
their leaves).
IMPORTANCE-ECOLOGICAL
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Habitats, nurseries, and nesting sites.
Root systems –harbor many organisms that
trap and cycle nutrients and other
chemicals.
Contribute to higher water quality.
Protect shorelines from erosion.
IMPORTANCE --ECONOMIC
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Food--- edible fruits and honey from flowers of
some species. River mangrove—source of best
honey.
Medicines- Treatment of skin disorders and sores
including leprosy. Headaches, rheumatism,
snakebites, boils, ulcers, diarrhea, and many more
conditions are traditionally treated with mangrove
plants.
Hard wood -- used for boat building and cabinet
timber.
WHAT ARE SOME OF THE THREATS TO MANGROVE
ECOSYSTEM?
WHAT ARE THE CONSEQUENCES OF MANGROVE
DEFORESTATION?
For Wednesday, October 31. Six students will be selected
randomly, and asked to give a presentation (informally) on
“Threats to Mangrove Ecosystem with reference to a
particular country, and management plan to save
mangrove forests.”
QUESTIONS
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Where did mangroves originate? How did they migrate to other places in the world?
What is vivipary? What is its advantages?
What are the different adaptations of mangroves to prevent excessive transpiration?
The root system has many unique types of roots in mangroves. Describe the various
types of aerial roots found in mangroves.
How do mangroves cope with salts?
What are facultative halophytes?
What are lenticels?
Describe the ecological importance of mangroves.
How are mangroves useful to humans? List at least three uses.
What are some of the threats to mangroves? What are the consequences of mangrove
deforestation?
References
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http://www.floridaplants.com/mangrove.ht
m
http://www.leecounty.com/DCD/Environm
ental/Mangroves.htm