colonisation & succession

8/14/2019 Colonisation & Succession

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COLONISATION & SUCCESSIONCOLONISATION & SUCCESSION


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COLONISATIONCOLONISATION

takes place in newly formed areas

Example: an environment of sand and

stonesThe first colonisers are called pioneer

species.


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PIONEER SPECIESPIONEER SPECIES

Have special adaptations Can survive on dry and nutrient poor soil Usually are hardy plants which have dense root

systems to bind sand particles, water and humus Short life cycle When they die, their remains add to the humus content

of the soil Pioneer species establish conditions that are more

conducive to other species that is called successorspecies.


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DOMINANT SPECIESDOMINANT SPECIES

Can grow faster and can out-compete the

pioneers which grow at a slower rate

As time passes, the dominant species modify

the environment which allows larger trees togrow

Gradual process through which one community

changes its environment so that it is replaced

by another community is called succession.


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CLIMAX COMMUNITYCLIMAX COMMUNITY

Ecological succession leads to a relativestable community which is equilibriumwith its environment.

The stable community is called a climaxcommunity.

A climax community is a stablecommunity that undergoes little or nochange in its species composition.


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Example of pioneer species: lalang,

grass

Successor species: HerbaceousDominant species: Shrubs

Climax community: Rainforest


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COLONISATION & SUCCESSION INCOLONISATION & SUCCESSION IN

MANGROVE SWAMPSMANGROVE SWAMPSPioneer species: Avicennia sp and

Sonneratia spCharacteristics: long underground cable

roots that support them in soft andmuddy soil

The roots also produce hundreds of thin,vertical breathing roots calledpneumatophores


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PneumatophoresPneumatophores


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COLONISATION & SUCCESSION INCOLONISATION & SUCCESSION IN

MANGROVE SWAMPSMANGROVE SWAMPS

Dominant species: Bruguiera sp.Has buttress root forms loop that

protrude from soil to trap more silt and

mud.This modifies the soil structure gradually.Over time, terrestrial plants such as Nypa

sp., Pandanus sp., begin to replace theBruguiera sp.

colonisation & succession

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