Ecological succession is the gradual process of change and replacement of species in an ecological community over time. It can occur naturally after disturbances like fires, landslides, or human activities that clear existing vegetation. Primary succession begins on new areas without soil, like lava flows, where lichens and mosses establish, enriching the soil over decades/centuries until trees form a climax community. Secondary succession follows disturbances where soil remains, allowing faster recolonization through seeds/roots. The Miyawaki method plants native tree seedlings close together to rapidly recreate native forests in urban areas. Rao Jodha Desert Rock Park restored a rocky wasteland through invasive species removal and native plant reintroduction.

1. ECOLOGICAL SUCCESSION

2. What is Ecological succession?
• It is a gradual process of change and replacement of the
types of species in a ecological community over time.
• The time scale can be decades or even millions of years
after a mass extinction due to some disturbances.
• Succession may be initiated by some of the disturbances
such as a from a lava flow or a severe landslide or by fire or
a severe wind throw .
• A D Malle was the first to make use of the term succession
considering development of vegetation after forest clearing.
• Henry David Thoreau wrote an address called “ The
succession of forest trees” in which he described about oak-
pine forest.
• The Austrian botanist Anton Kerner published a study
about the succession of plants in the Danube river basin in
1863
Danube river basin
Oak pine forest

3. Stages of succession
As soon as the suitable bare site for succession is available the process involves the
following stages.
1. Colonization
• This process involves the invasion of the bare area by the seeds and spores of the
plant growing in the neighboring communities or from far off places through the
agency of wind, water and animals.
• The nature of bare area determines the type of plants it can grow.
Colonization includes following steps –
a. Migration - Arrival of reproductive bodies and plant propagules from other places.
b. Ecesis – This process involves establishment of the initial plants on the bare area.
i.e germination of reproductive bodies.
c. Aggregation – The species become establish in an area, they flower, fruit and
produce seeds. Increase in no. of species.
d. Competition – Involves struggle for existence between two or more individuals
growing in an area. Such struggle is between plant of same kinds.
e. Reaction – This includes effect of plant growth on the habitat. Plants alter habitat
conditions
If bare area is pond, seeds of water
plants will germinate
In case of desert seeds of xerophytes
will germinate

4. Primary
succession
Secondary
succession
Types of succession
The process of creating life in an area where no life
previously existed.
An example of an area in which a community has never
lived before, would be a new lava or rock from a volcano
that makes a new island.
The process of restabilization that follows a disturbance
in an area where life has formed an ecosystem.
An example of such an area could be land affected by
fires, landslide etc.

5. Primary succession
Begins at a place without any soil.
• In the beginning there is only rocks, sand or volcanic ash . Since there
is no soil, there is no community
• For presence of soil there must be nutrients like nitrogen.
Lichens begin to grow on the rocks.
• Over many years lichens breakdown the rocks into sand. Weathering
and erosion process also break down the rock into sand.
• Lichens do not need soil to survive and are called Pioneer species

6. Nitrogen cycle begins
• Some lichens grow large and some die. Decomposers arrive and break
down the lichens. The dead lichens and waste materials of the
decomposers enrich the sand. Eventually enough nutrients enter the
sand and it becomes soil.
Mosses begin to grow
• Seeds are blown in by the winds and or carried by the animals. Simple
plants like mosses can grow into the new soil.
• These plants grow and soil gets enriched as these plants die.

7. Herbs and weeds start growing
• The simple plants die adding more organic material to the soil.
• The soil layer thickens and grasses, wildflowers and other plants begin
to take over.
• Medium sized animals and birds make this their habitat.
• Vegetation grows close together, reducing the amount of space
available for growing.
• Lichen and other new species compete for the same space and
eventually lichens die out and other species survive.
Shrubs and trees start growing
• These plants die, adding more nutrients to the soil.
• Shrubs and trees can survive on this soil.
• Insects, mammals and small birds begin to move in. Once a bare rock
now supports a large variety of biodiversity.

8. Large trees start growing.
• Small trees and shrubs die and add more nutrients to
the soil and now large trees can start growing – Climax
community
• A CLIMAX COMMUNITY is a mature, stable community
that is the final stage of ecological succession. In an
ecosystem with a climax community , the conditions
continue to be suitable for all the members of the
community.
• Any particular community has its own set of climax
species, which are the plants that are best adapted for
the area and will persist after succession has finished,
until another disturbance clears the area.

9. • Temperature and amount of rainfall are the two main physical factors that determines the nature of community that
develops in an area.
• If we place the amount of rainfall on a graphs x-axis , from 0-10 , 10-20 and 20-30 + inches and the temperature along
y axis from hot, moderate to cold, the various types of ecosystems will fit into the graph based on the conditions that
they require.

10. PIONEER SPECIES INTERMEDIATE SPECIES CLIMAX COMMUNITY
Thousands of years
Primary succession

11. What if ?

12. Threats to climax community
• FOREST FIRES
• FLOODING, VOLCANIC ERRUPTIONS
• CLEARING A COMMUNITY FOR AGRICULTURE
• ANTHROPOGENIC ACTIVITIES
• Anything that destroys the existing community , but much of the soil remains Sometimes some of the organisms
remain as well.

13. Secondary succession
•Organisms are destroyed but the soil is safe.
•The soil already contains the seeds of weeds, grasses, and trees. More seeds are carried to the area by wind and birds.
•Succession begins again but the primary species are different.
•Because soil is present, this succession is faster.
1.
Some seeds in the soil
begin to grow.
2.
Larger shrubs move in
3.
Fast growing trees
(such as pines)
move in
4.
These are followed by slower-
growing hardwood trees

14. Secondary succession
• Climax community is a stable group of plants and
animals that is the end result of the succession
process.
• Does not always mean big trees, it could be
– Grasses in prairies
– Cacti in deserts

15. Secondary succession
• The process of secondary succession takes lesser time since the soil for growth of vegetation still exists.

16. Circle of life in Secondary succession

17. Secondary succession of an Oak and Hickory forest

18. CLASSICAL
SUCCESSION
THEORY
NEW
SUCCESSION
THEORY
–
MIYAWAKI
Soil of a natural forest-
Soft
Moist
Fertile
Nutritious and presence of fungi
Presence of microbes
Presence of humus
Miyawaki method involves planting of climax
species directly and creating a forest in 25-30
years.
Tree species identified are native to the
particular place these forests are grown.
Dr. Akira Miyawaki, Japanese botanist

19. Multi layer forest

20. Till date, 2,21,405 trees have been planted at 43
places using the Miyawaki plantation technique in
Mumbai
Here are some images from the Urban Forest
Plantation using Miyawaki Method at Chandivali Hill
Garden that has 27,900 trees.
Urban forest in Mumbai

21. Rao Jodha Desert Rock Park
Jodhpur city, Rajasthan
Aim of the restoration project
To eradicate Prosopis
juliflora from the entire rocky tract
and restore the area with plants
native to rocky parts of the Thar
Desert.
This is how it looked before– lots of invasive P. juliflora
Team: Pradip Krishen, Somil Daga
Plus employees of the Trust

22. • Work in Rao Jodha Desert Rock Park began in 2006 to try and restore the natural ecology of a large, rocky
wasteland next to Mehrangarh Fort in Jodhpur. It had suffered years of neglect and was overrun by
invasive Prosopis juliflora whose seeds had been broadcast from the air in the 1930s.
• The challenge was to eradicate P. juliflora and understand how native rock-loving plants would adapt to conditions
here. In 2011 a visitors centre was created and trained Naturalist guides to take visitors around.
1. Clearing the Site
Excavation was done upto 45
cm below ground-level in order to
"grub out" baavlia
2. Collecting our plants
Plants that are adapted to growing
in arid, rocky areas of the Thar
desert.
2. Planting out and caring for them
Understanding what newly introduced
plants required.

23. Newly planted species in the Park

26. Eco India: In space-strapped Mumbai, citizens are using a Japanese technique to create
green cover
https://www.youtube.com/watch?v=uTY6nvA7fZY
Forest Making Workshop in Central India-
https://www.youtube.com/watch?v=iDoNEdW_KXo
Forest Making in Beirut
https://www.youtube.com/watch?v=uweu9s4tbFM
Maruvan, jodhpur
https://www.youtube.com/watch?v=2REXsRK_mqs&t=1s