Mangrove Swamps

..Before you go into details about the process of colonisation in mangrove swamp, you have to understand the meaning of certain terms like colonisation, pioneer species, successor species, dominant species, succession, and of course climax community...


..As the processes of colonisation and succession in a pond, there was an essay question asked in 2007....

QS9(a) Diagram shows the process of colonisation and succession in a habitat. (Diagram shows the pond)
What is meant by 'colonisation and succession in a habitat'? Based on Diagram, explain how colonisation and succesion bring about the formation of primary forest in a habitat. [10 M]

Answer:

• Colonisation is a process whereby a species colonises in a newly formed area/ habitat/pond. [1m]
• Succession is a process whereby one species of organism changes the habitat , then being replaced by other species which are more adaptable to the habitat. [1 M]

...next 8 points are to explain how colonisation and succesion bring about the formation of primary forest:

P1- Pioneer species /submerged plants causes a change in the environment

P2-the remains of plants and decayed body deposited to the pond bed

P3-pond becoems shallower

P4-nutrients are added to soil/pond water

P5-lead to the growth of floating plants to replace submerged plants

P6-Floating plants cover the water surface, preventing the light to penetrate water

P7-result in greater rate of plants death which sink to the bottom of the river

P8-making the pond shallower

P9-floating plants are then slowly replaced by amphibious. emergent plants

P10-the successor causes further changes to habitat/pond

p11-finally amphibinas plants are replaced by land community which dominate the area.

[Any 8 marks]

The details about mangrove swamps are not yet asked... So why not we consider it this year..since there are so many facts about mangrove swamps which could possibly be asked...

Mangrove swamps are found in tropical and subtropical regions where freshwater meets salt water


Their characteristics include:
i. soft, muddy soil
ii.higher concentration of salt
iii.very low level of oxygen due to waterlogged condition
iv.Exposed to a high intensity of sunlight.
v.strong wind

Their characteristics are THE FACTS and you have to elaborate with EXPLANATION...by asking SO WHAT??

....soft, muddy soil....so what??..
....higher concentration of salt...so what???..

And mangrove swamps along tropical bays characteristically show ZONATION...(Refer text book or any reference book )


...and you should be able to identify which species are distributed in different zones...
..and the spelling of each species...and their adaptive characteristics..

Avicennia sp and Sonneratia sp (Perapat)are pioneer species of mangrove swamp.

Avicennia sp (api-api) with pneumatophores- the breathing roots which grow vertically upwards from the mud. Gaseous exchange takes place through the pores in the pneumatophores...The roots are also long branched cable roots.

Rhizophora sp has prop roots..to give support . It gradually replaced the pioneer sp.


Prop root trap more silt and mud.. Soil then becomes firmer and rier.. The soil level is raised and is more fertile with the collection of decaying plants parts..This condition favors Bruguiera sp to replace..
Bruguiera sp has buttress root..which trap more mud and silt causing the land structure to change..

The viviparity seeds: which attach and germinate at the mother's plant

Salt that enters the root from sea water will be excreted through hydathodes.

...Question:

Explain the problems faced by mangrove plants and how they overcome it. [10 marks]

Tips:

• Remember: FACTS and EXPLANATION [ 5+5 Marks]
• You may explain according to species
• or according to its zonation

Questions:

Diagram below shows a mangrove swamp at a river mouth in 1950 and 2007 respectively. The line XY shows the position of the beach.

(a) i) What has happened to the mangrove zone in diagram 3. [ 1m]
ii) Name the process that is taking place. [ 1m]
iii) Explain the process mention in (a) ii [3 m]

By using suitable keys, sketch the zones of mangrove swamp in diagram 4 ii) in which
the following mangrove trees can be found.
Brugueira sp, Avicennia sp, Rhizophora sp. (3 marks)

c) i) State the type of seedlings produced by the mangrove trees. (1 mark)
ii) Explain how this type of seedling increases the chances of survival of the mangrove
trees.(2 marks)

d) State one problem faced by mangrove trees. Explain how mangrove trees overcome this
problem.( 2 marks )

Answer:

(a)i.They have been moved from their original position

ii. Succession

iii -The roots of the pioneer species trap the mud, causing the soil to become more compact
- At the same time the soil level increases, thereby exposing its exposure to the tides and this makes the soil unsuitable for the pioneer species .
- The species in zone U are the successors , which take over the area of zone T
- Slowly, succession of the species in zone W takes place.

c.i. Viviparous seedling

ii.- The seedling are able to germinate while still being attached to the parent plant.
- As the seedling fall into the water , they can float horizontally and, subsequently, get washed up on mudflats where they settle and grow into new plants

d.- The mangrove trees are exposed to direct sunlight which results in a high rate of transpiration.
- This problem is overcome by the thick and succulent leaves of mangrove trees which can store water .