Created by hazimah.azhar
over 10 years ago
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SUCCESSION is a series of changes that take place in a plant community over time
If undisturbed, succession will reach it's final stage called it's climatic climax: this is when the plant species are in perfect balance with the environmental conditions
Although, climate plays a major factor in influencing plant growth. However, on a local scale other factors such as:-relief-geology-drainagecan affect plant growth (locally)
There are two basic types of succession Primary succession Secondary succesion
PRIMARY SUCCESSIONOccurs on surfaces where there had not been previous vegetation e.g. lava flows, bare rock and sand dunesTwo main types of primary succession: Xerosere- formed on dry land, this can be subdivided into (1) lithoseres-bare rock (2) psammoseres- sand dunes Hydrosere- formed in water, this can be subdivided into (1) haloseres-salthy water (2)hydroseres-fresh water
SECONDARY SUCCESSIONThis occurs after an area of existing plant community has been modified due to human interference by deforestation or naturally by landslide or fire caused by lightning
Development of a succession
Lichens is a fungus that has algae living inside of itIt first attacks on the bare rock surface. These pioneer species are hardy plants as they are able to withstand such harsh conditions (adapted)They do not require the need of soil as they are the main agents of creating the soil by breaking/attacking the rock
They compete for space, light, water and nutrients
Microclimate - the climate of a very small or restricted area, esp. when this differs from the climate of the surrounding area.
They can affect the microclimate of the conditions:shelter, temperature, humidity
The roots of the pioneer plants help to break/weather the surface and so to aid soil formation
As it develops, it passes through a series of stages called seres
There is the creation of immature soil, and this enables other plants to colonise and change the existing balance of species
Each stage provides better conditions for plant growth than the previous one as the addition of organic matter (decaying vegetation) is added to the developing soil this helps to improve it's structure and water retention qualities
Example of a plant succession:
Lithosere
Starts on a newly exposed rock surface that has might've been created by an eruption of a volcano leaving a new,bare lava surface
Raised beach
Raised beach, the west coast of Scotlandcaused by either:(1) A fall in sea levels(2) By the isostatic uplift of land form the sea
Initially colonised by bacteria and algae that can survive in such harsh conditions Pioneers begin to colonise, lichens. They can withstand the acute water shortage and help to assist water retention As water retention improves, moss begins to grow. This help to further improve water retention. Also weathers the rock to produce soil which encourage advanced plants to grow Ferns, herbs appear. When they die, the bacteria recycles the nutrients by converting the remains to hummus which further improves soil fertility Shrubs grow, shading grass and herbs Pioneer trees are established. They are fast growing species (birch) Slow growing tree species begin to develop such as ash and oak
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