CHARACTERISTICS OF MANGROVE TREES
· A root system that spreads out widely to provide support for the mangrove trees in the soft muddy soil.
· Breathing roots that protrude out of the soil and which are called pneumatophores. In waterlogged soil which lacks oxygen the pneumatophores enable gaseous exchange to occur at the roots.
· The roots of mangrove trees can withstand the highly saline seawater by having the osmotic pressure of the cell sap in the roots higher than the surrounding seawater. As a result, plasmolysis cannot occur. Instead the roots can absorbed water by osmosis. [Hydathode (pores) in the epidermis of leaves secrete excess salts from the plants: to control the osmotic pressure of the cell sap.]
· The leaves of mangrove trees have thick cuticle and sunken stomata to reduce transpiration in a hot environment due to the strong sunlight. The leaves are also thick and succulent to store water.
Many mangrove trees have vivipary seeds that begin to germinate while still attached to the parent tree. This ensures that the seeds will get sufficient oxygen from the atmosphere during germination and will not be suffocated for lack of air in a waterlogged environment. It also prevents the seed from dehydration in the highly saline seawater.
MANGROVE PLANTS AND ANIMALS
Wildlife in mangrove swamp . Terrestrial fauna is also found in mangrove and includes insects, snakes, frogs and mammals such as possums and flying foxes. There are also mudskipper horseshoe crab and crab in the pioneer ( Avicennia sp. and Sonneratia sp.) and successor species ( Rhizophora sp. and Bruguiera sp.). There are also terrestrial plants like the nipah plam and pandanus sp.
Mudskipper - Mudskippers are gobies that have become adapted to an amphibious lifestyle. Mudskippers range in size from 6 to 10 inches. Beneath the surface of the water, the Mudskipper digs mudflat burrows that are used for refuge and spawning.
Fiddler Crab - it is only the male Fiddler crab that has one claw significantly larger than the other. The male uses it to court females. If for some reason the larger claw is lost, the remaining smaller claw will grow larger and the lost claw re-grows as the smaller one! Fiddler crabs can't swim!
 Saltwater Crocodile - Saltwater crocodiles are the largest of all the crocodilian species. Although reportd to exceed 27 feet in the wild, individuals over 17 feet are rare. Several crocodilian species can use their tail to propel almost their entire body out of the water! |
Mangrove Monitor - Monitor lizards are semi aquatic and spend much of their time in or near water. Most adult Mangrove monitors average between 2 1/2 and 4 feet in length (including tail). |
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Red Mangrove - grows seaward with high arched prop roots extending out in tiers that turn downward from the trunk. It gives the illusion of trees on 'stilts'. Oysters attach themselves to these roots where they are covered during high tide. The underwater roots of Red mangroves serve as nurseries for newborn fish. |
White Mangrove - often occurs at the landward edge of Mangrove Swamps in a stunted form. The leaves are glossy green above with a distinctive pale grey underside which is also slightly hairy. The most readily distinguishable feature of the white mangrove is the presences of numerous spongy pneumatophores(peg roots) which spread out around the base of the tree. Peg roots grow vertically through the soil surface to allow the mangrove to breathe.
Saltbush - a many branched shrub that grows about 12 feet tall. It grows in just about any type of soil, including soil high in saline content, and does best in full sun. Its flowers look like silvery plumes.
Ferns- ferns were thriving on Earth for two hundred million years before the flowering plants evolved! Most ferns are leafy plants that grow in moist areas under forest canopy. Ferns reproduce from spores and an intermediate plant stage called a gametophyte.
THE MANGROVE COMMUNITY
Mangroves provide a habitat for many animals. The mangroves and their associated organisms are collectively called the mangrove community. Because of the vertical extent of the trees, terrestrial animals can occupy the upper levels of the community while truly marine organisms can occupy the bases.
Larger organisms of the Rhizophora, or red mangrove community can be grouped into three general categories.
1. Those which inhabit the roots. They represent the hard bottom component of the community.
2. Those that live in the soft sediment that accumulate around the base of the mangroves.
3. Animals that can enter and leave the mangrove community. This represents the transient component. They generally rely on the other two community groups for sustenance.
The dominant groups of marine animals in the mangrove forests are molluscs, certain crustaceans and some fishes.
Animals living above the waterline on the prop roots of the red mangrove include the mangrove periwinkle, Littorina angulifera, the isopod, Ligia, and the mangrove crab, Aratus pisonii
The periwinkle is a browser and feed on the lichens that grow on the bark of the red mangroves. The mangrove crab, Aratus, lives about the water line but will submerge and cling onto the roots below the waterline for protection.
a host of invertebrates life on the roots below the waterline. The mangrove oyster, Crassostrea rhizophorae, the flat tree oyster, Isognomon alatus, barnacles (Chthamalus and Balanus) and mussels (Brachidontes) are common.
Lower in the root region a number of encrusting attached organisms can be found including several species of sponges, bryozoans, hydrozoans, and the fan worm, Sabellastarte. Like the bivalves and bryozoans, fan worms are filter feeders.
Another component of the red mangrove community includes organisms that live on the soft mud bottom such as swimming crabs (Portunidae) and various bivalves. The crabs are transient. The mud is usually anaerobic but the bivalves have siphons that allow communication with the oxygenated water above the bottom.
Mud flats associated with mangrove forests are inhabited by a number of crabs. Some, such as the fiddler crab (Uca) burrow in the soft mud. Goniopsus cruentata, known as the ³mangrove tree crab², is often seen among the mangrove roots near the water¹s edge. It inhabits the mud flat but does not construct burrows, but may take refuge in other crab¹s burrows such as the borrows of Ucides cordatus. U. cordatus is found in the mud flat near the shoreline. Young land crabs, Cardisoma guanhumi are also found burrowing in the mud flats but adult Cardisoma prefer drier habitats for borrowing.
Mangrove forests form nesting and roosting sites for many large birds.
ZONATION OF MANGROVES
In the Caribbean there are three principal mangrove species plus a dozen or so woody halophytes. Mangrove trees have different degrees of tolerance for exposure and submergence of their roots to seawater, thus the tidal fluctuation results in zonation just as in other intertidal habitats.
The red mangrove (Rhizophora mangle) is the pioneer mangrove in the Caribbean (first to grow in newly exposed muddy shore). It grows as a dense tangle in the water along the edge of the shoreline. Their arching prop roots provide an excellent habitat for many invertebrates. Shoreward from the red mangroves, but still in damp soil, are the black mangroves (Avicennia mangle). The black mangrove fares best where there is occasional inundation, but not by diurnal tides. They are characterized by prop roots that extend from the lateral branches but do not produce the tangle of roots seen in the red mangroves. They also have many pneumatophores that extend upward from the roots around the base of the trunk.
REPRODUCTION
The reproductive potential of red mangroves is high. Flowers are produced throughout the year. The seed germinates and remains attached to the parent tree. Long greenish-brown seedlings called "droppers" hang like daggers from the branches. Eventually they fall into the water where they float upright and they may be dispersed by currents. When they encounter shore, the seedlings put out roots and begin to develop leaves.
USES OF MANGROVE
From an ecological perspective mangrove are a unique and significant ecosystems. They support a diverse range of plants including plams, trees, shrube and even ferns, which have develop unusual adaptations to the prevailing environment conditions. In fact these plants have been so successful in their development that mangrove are among the most productive natural systems found throughout the world.
Mangrove are used by a vast array of organisms as breeding, nursery and feeling areas. They also play a valuable role in foreshore protective, reducing evosion by cyclones and lessening the impact of strom surge.
Mangroves also provide important permanent and temporary habitats for a large number and rage of marine and terrestrial fauna. Marine fauna commonly found in mangrove includes mollusks, crustaceans (such as crab and prawns) , a wide range of fish and of course, the saltwater crocodile.
Colonisation and succession in mangrove
v The communities in an ecosystem are subject to disturbance which, in turn, lead to change in the plant and animal communities over time.
v Colonisation is the process when air, water nutrients and sunlight are available, spores and seeds of certain plants starts to germinate and grow.
v Succession in the process in which are community changes the environment so that it is replace by another community.
Ø The pioneer species of a mangrove swamp are sonneratia sp. and avicennia sp. this species gradually changes the physical environment of the habitat. The extensive root system of tis plant trap and collect sediment, including organic matter from decaying plant parts
Ø It time passes, the soil becomes more compact not frim. This condition favours the growth of the Rhizophora sp. Gradually the Rhizophora sp. replace the pioneer species.
Ø The prop root system of the Rhizophora sp. traps silt and mud, creating a firmer soil structur over time. The ground become higher cause the soil to be driver because it is less submerged by the sea.
Ø The Bruguiera sp. starts to replace the Rhizophora sp. The buttrees root system forms lops which extend from the soil to trap more silt and mud.
Ø The shore extends further to the sea over time terrestrial plant like the nipah palm ( Nypa fruticans) and Pandanus sp. begin to replace the Bruguiera sp.
HABITAT DISTRUCTION
Dredging
v Dredging suffocates mangroveess when the aerial roots become flooded,preventing oxygen from reaching the root system.
Dredging and filling activities have caused flooding of mangrove habitat. Standing water covers the aerial roots, making it impossible for oxygen to reach these specialized roots as well as the underground root systems. Eventually this leads to the deaths of mangrove trees.
Water pollution
v Herbicides , oil spills and other types of pollutante may kill mangrove.
Causing tremedous damage to mangrove, herbicides, oil spills, and other types of water pollution may result in the death of these plants. Mangrove are very susceptible to herbicides.
Oil spills cause damage to mangrove by coating root, limiting the transport of oxygen to underground roots. Mangrove communities including invertebrates, fishes, and plants are also highly susceptible to damage from petroleum products.
Urban Development
v Urban development of areas in and near mangrove result in the destruction of this habitat as well as other associated wetland habitats.
Responsible for total loss of mangrove habitat in some location, when urban development includes the construction of buildings and canal systems as well as the consumption of water by a growing human pollution. Human activity upland from mangrove may also impact water quality and runoff. These land and coastal activities result in increased evasion as well as the reduction of nursery areas supporting commercial and game fisheries.
Problem faced by mangrove swamp
1. Soft muddy soil and strong coastal winds pose support problems.
· Avicennia sp. have long,highly branched underground cable roots.
· Rhizophora sp. have prop roots.
· These roots, also known as aerial roots, anchor the plants onto the muddy soil.
2. Waterlogged conditions of the soil reduce the amount of oxygen available and lead to an anaerobic environment.
· The Avicennia sp. has breathing roots called pneumatophores which grow vertically upwards.
· Gaseous exchange also occurs through pores called lenticles .
3. Direct exposure to the sun leads to a high rate of transpiration in the mangrove plants.
· The leaves are covered by a thick layer of cuticle
· The leaves are thick and succulent, and able to store water.
4. The high salinity of the sea water makes the surroundings water in the soil hypertonic when compared to the cell sap of the root cell.
· The cell sap in the roots cells of the mangrove trees has a higher osmotic pressure than the soil water that surrounds them.
· The excess salt in the hypertonic solution of the soils enters the roots and is then excreted as crystalline salt from the hydathodes through the process of guttation.
5. Seeds which fall onto the ground die because they are submerged in the soft and waterlogged soil.
· The mangrove trees practice viviparous seedlings.
Adaptations
· To overcome the problem of stagnant water and reduced oxygen content, the pioneer plant have vertical aerial roots known as pneumatophores.
· Pneumataphores are roots that project vertically up from the mud and into the air.
· At the end of pneumatophores are aerenchyma tissue for gaseous exchange.
· Aerenchyma is a type of parenchyma tissue with plenty of air spaces between its cells that enable the root to float and also to facilitate gaseous exchange.
· Pneumatophores trap mud and organic sediment and the amount of soil increases and become more compact and firm as time passes. This will make the habitat suitable for succession by other plants such as the Rhizophora
· Mangrove trees can germinate by viviparous seedlings.
· Mangrove trees also have hydathodes, the pores in the epidermis of the leaves.
Asked Question
Essential Question: How do mangrove trees adapt to living in swampy area?
Answer : by pneumatophores, prop roots, lenticels, hydathodes, vivipary see
Unit Question : What is the problem faced by mangrove plants living in swampy area?
Answer : Salt water, rough wind, muddy soil and wave.
1) State five adaptive features of the plants to enable them to live the mangrove swamps.
i. Prop root as support root in soft muddy soil and coastal winds.
ii. Pneumatophore as breathing root.
iii. Leaves with thick layer of cuticle reduce transpiration during hot days.
iv. Cell sap in the root cells ensures that the roots do not lose water by osmosis.
v. Vivipary increase the chance of survival of the mangrove.
2) Write a sequence of the names of mangrove plants to show how succession occurs in a mangrove swamp.
Pioneer species.(Avicennia sp. and sonneratia sp.) successor species ( Rhizophora sp.) successor species (Bruguiera sp.) terrestrial species (Nipah palm and Pandanus sp.)
3) What are the problems faced by mangrove swamp living in swampy area and how they overcome that problem?
Problem-salt water. muddy soil
Overcome-hydathodes (salt water)
-roots(muddy soil)
4) How are Rhizophora sp. and Sonneratia sp. Adapted to the conditions in a mangrove swamp?
Prop roots to support the trees in soft and muddy soil.
Vivipary seed to ensure that the seedlings can grow not carry away by the sea water
About Borneo Paradise Eco Farm Resort SABAH has been known to have the best coast resources in Malaysia. She has approximately 1800Km of coastline and the largest areas of mangrove swamps in the country. Majority of the mangrove swamps are preserved in the mangrove forest reserve and sustainable management of the mangroves must be kept because the existence and heath of mangroves are known to support a large proportion of marine lives. The endeavors to preserve the existence of the mangroves as part of the environmental landscape for eco-tourism development and also the essential ingredient for aquaculture development.
The Resort Background
What was started 18 years ago as a private oriented hideout has grown over the years to become what it is now-a simple, modern wooden infrastructure with facilities in total harmony with the surroundings. Throughout the years it has evolved from a simple unsophisticated structure, to culturing of seashells and animals rearing deers, goats, buffaloes and ponys. The outdoor activities include canoeing, boating, trolling, fishing, mountain biking, jungle trailing and obstacles challenges. There is also the feeding of monkeys in the surrounding habitat with the excess bananas procured from the neraby plantations. A small hall was added at the request from many visitors to conduct passive indoor activities.
It has remained as a private outfit until requests from visitors and friends necessitated a need to emplace a simple management to accomodate the growing demand. It was decided that the gift of nature at this place be shared with others. An entity was incorporated under the style of “Borneo Paradise Eco Farm” in 1999 and a business license was procured from the authorities to address the incessant demand.
Since the opening of the resort to the public, the majorityof the visitors are from the nearby towns of Tawau, Kunak, Lahad Datu and to this date all over Sabah. The guest normally indulged themselves to family barbecues and fishing activities. The school children organize their programme under the close supervisionof their teachers. Security is well look after with a permanent post stationed by the security forces (Pasukan Gerakan Am) to monitor the surrounding resort.
REFERENCES
http//www.wikipedia.ag/wiki/mangrove.
www.yahoo.com/mangrove+swamp.
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