A detail notes on plant succession

1. "ECOLOGICAL SUCCESSION"
BY MUHAMMED REHAN
ForesterRehanUOS@yahoo.com
+923469792050
INSTITUTE OF AGRICULTURE SCIENCES AND FORESTRY
1

2. A change in the composition and nature of a plant community of a particular
habitat over the years is called plant succession or ecological succession.
Plant succession may be of two kinds:
1. Primary Succession
2. Secondary Succession
It is the initiation of vegetation on bare or newly exposed area such as
land exposed as a result of soil erosion,melting glacier,volcanic eruption etc.
 It begins in areas which have previously been unoccupied by plants,
open water,bare rocks or sand.
 Lichens are the first plants to be appear.
 Here no soil is present at the time of initiation.
 It takes long time to reach Climax.

3. 2
This kind of succession begins where ever the existing vegetation has been
destroyed.It usually starts after forest fire,cut the trees,flood and erosion.
 It takes shorter time i-e 50--100 years for grasses and 200 years
for clear forest.
 It has soil at the time of initiation.
Plant succession at particular kind of habitat is usually called sere. The different
seres are:
1.
when the succession starts in equatic habitat.
2.
when the succession starts on a dry,bare land.
3.
when the succession starts on bare rock surface.
4.
when the succession starts on sandy habitat.
E.g Spinifex , Ipomoea biloba
5.
when the succession starts in saline soil or water.Here the
pioneer plants usually have succulent leaves and stem.
E.g Chenopodium , Basella and some specie of Asclapias.

4. 3
6.
It is the succession of micro organism and lower plants on dead
plant parts and bodies.
Plant succession have the following processes.
1.
An area is exposed
2.
The process of dispersal of seeds , spores and other structures
of propagation of species to bare area is called migration.
3.
it occures when the condition are favorable.
4.
successful germination of propagules and their establishment in the
bare area.
5.
After ecesis the individual of species increases in number as a result of
propagation.
6.
Due to limited resources species shows both inter and intraspecific
competition. This result into the elimination of plants due to
competition.
7.
Various other plants try to established in the spaces left by
the elimination of plants due to competition.
8.
The newly arived plants interrupt with the existing ones.As a result
reaction environment is modified and becomes unsuitable for existing
community which sooner or later is replaced by another community.
9.
Finally there occurs a stage in the process when the community is
stabilized for a longer period of time and it can maintain itself in
equilibrium within that climate.This is called climax

5. 4
Plant succession has the following stages.
1.
 It is the first stage of ecological succession
 Here relatively few,very simple species exist.
 These plants may be mosses and lichens
2.
 It is the second stage of ecological succession.
 Here the plants emerged including annual herbs,grasses and shrubs
 These plants are fast growing and produce million of seeds which
help to produce dominant position in plant community.
 They die on annual basis providing more nutrients to soil.
3.
 Perennial shrubs will come to dominate the
landscape out-performing the grasses and shrubs.
 The are larger,having deep root system,receive more sun light
and nutrients and their growth will remain rapid.
 Soft wood saplings also grow in this stage.
4.
 As the soil improve small tress will begin to grow.
 These are generally fast growing trees.
 These trees will eventually take over the community forming young
forest.
 The soil will continue to improve by leaf litter.
 The tree canopy will shield shrubs and grasses from the light
and will be died.
5.
 This stage occurs when the plants within the community achieve
a state of equilibrium within the environment.