COASTAL ECOSYSTEMSMANGROVES

BIOL 202 MARINE BOTANY

FALL 2009

What are Mangroves? 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 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 MangroveRed Mangrove

Sweet Mangrove

White Mangrove

Viviparous propagule

ORIGIN OF MANGROVES Indo-Malayan region. Spread westward by

ocean currents during the Late Cretaceous and Lower Miocene.

Seeds and propagules.

Characteristics of Mangroves

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 radicle- characteristic of Rhizophoraceae .

Root system has many unique types of roots. 1. Stilt-roots, 2. Pneumatophores, 3. Root knees. 4. Plank Roots

ROOTS STILT ROOTS--looping roots

arise from the trunk and lower branches

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 KNEED ROOTS-

the horizontal roots growing vertically upwards and forming loops downwards to resemble a bent knee.

PLANK ROOTS-wavy, snake-like roots that radiate outwards from the trunk base.

                                                                 

Lenticels 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? Facultative

halophytes Grow in fresh water

+ salt water.

                                                                                                                     

   

COPING WITH SALT Exclude Salt (no

intake) Extrude salt (take

salt in and dispense it through glands in their leaves).

IMPORTANCE--ECOLOGICAL

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 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 MANGROVEECOSYSTEM?

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 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 http://www.floridaplants.com/mangrove.ht

m http://www.leecounty.com/DCD/Environm

ental/Mangroves.htm