Ecological succession

Ecological succession-pioneer species-process of succession-climax concept-types (primary & secondary)- example

1. ECOLOGICAL SUCCESSION PRESENTED BY SAIKAT JANA SEM-IV ROLL-91 DEPT. OF BOTANY NARAJOLE RAJ COLLEGE

2. WHAT IS ECOLOGICAL SUCCESSION This is the process by which the structure of a biological community  evolves from a life less barren habitat to a stable community over time. The time scale can be million of years after a mass extinction due to some disturbances.

3. WHAT IS PIONEER SPECIES The pioneer species are hardy species which are the first to colonize barren environments or previously biodiverse steady-state ecosystems that have been disrupted, such as by fire. LICHEN FERN MOSS

4. PROCESS OF ECOLOGICAL SUCCESSION Ecological succession is completed through a series of sequential steps– Nudation Invation Competition and co-action Reaction Stabilization or climax.

5. 1. NUDATION – ● Nudation is the initiation of a new plant succession by a major environmental disbalance. CAUSES OF NUDATION ● CLIMATIC: Due to glaciers, dry periode, landslide etc. ● BIOTIC: Like forest destruction, agriculture, disease epidemics etc. Volcanic eruption Nudation of an area

6. Volcanic eruption Nudation of an area ● It is is second step of succession. ● Invasion is the successful establishment of a species in the bare area. ● Invation is completed in three steps– i. Migration ii. Ecasis iii. Aggregation 2. INVATION– Mosses grow on rock

7. i. MIGRATION ● Seeds, spores, propagule are reach in a bare area. ii. ECASIS ● Process of successful establishment of species. ● Seeds/spores germinate, grow and reproduce. ● Only few progenies survives. iii. AGGREGATION ● Individuals of a species increase their number and they stay close to each other. MIGRATION ECASIS AGGRESSION 2. INVATION

8. 3. COMPETITION AND CO-ACTION– ● Aggregation means a large number of species within a limited space. ● Competetion for space and nutrition. ● Competetion may be inter-specific or inter-specific. ● Individuals of a species effect each other (Co-action). ● Competetion and co-action results in: Elimination of unfit individuals. Survival of fit individuals. INTER-SPECIFIC INTRA-SPECIFIC

9. 4. REACTION– ● Most important stage in ecological succession. ● It is the modification of the environment through the influence of living organisms present on it. ● Due to reaction, change in soil, water, light and temperature etc. ● Due to the modification, the present community become unsuitable for the existing environmental condition. ● Such communities will be replaced by another community. ● SERE – The whole sequence of communities that replaces one another in the given area is called sere. ● Various communities contributing sere are called serial community.

10. 5. STABILIZATION OR CLIMAX ● Last stage of ecological succession. ● The community becomes more or less established for a longer period of time. ● The final community is not replaced and is known as climax community and the stage known as climax stage. Example of climax community FOREST GRASS LAND

11. TYPES OF ECOLOGICAL SUCCESSION ECOLOGICAL SUCCESSION PRIMARY SUCCESSION SECONDERY SUCCESSION

12. PRIMARY SUCCESSION This is a type of ecological succession in which plants and animals first colonize in a barren, lifeless habitat like rock surface. E.g.– A new island formed by volcanic activity. Bare rock surface Grassy rock Forest

13. EXAMPLE OF PRIMARY SUCCESSION The island of Surtsey formed by volcanic eruption off of the coast of Iceland during the period from 1963–1967 VOLCANIC ERUPTION

14. SURTSEY― POST ERUPTION

15. SURTSEY― TODAY

16. SECONARY SUCCESSION Secondary succession is the is the series of community changes which take place on a previously colonized but disturbed or damaged habitat. E.g. – Succession of a burned forest. A grassland The grassland on fire The bare area after fire New grass growing

17. EXAMPLE OF SECONDARY SUCCESSION Devastating forest fires at Yellowstone National Park ― 1988 It was the largest wildfire in the history of Yellowstone National Park in the United States. FOREST FIRE AT YELLOWSTONE NATIONAL PARK

18. YELLOWSTONE NATIONAL PARK AFTER FOEST FIRE

19. ONE YEAR AFTER FIRE (1989) TEN YEARS AFTER FIRE (1998)

20. 20 YEAR AFTER FIRE (2008)

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