1. Ecological Succession

3. SUCCESSION
Ecological disturbances (such as forest fires, floods, volcanic eruptions, and even glaciers) can destroy all actively growing organisms.
This results in a drastic change in the structure of the biological community.

4. SUCCESSION
Although the area appears barren, within months, new vegetation will sprout, and animals may repopulate the area.
This is called ecological succession.

6. PRIMARY SUCCESSION
Plants, such as the liverwort and lichens are some of the first organisms to inhabit a barren area. Bacteria and algae are also present.
These organisms are called pioneer species and they form a small community which will change the biotic conditions of the disturbed area.

7. PIONEER SPECIES

8. PRIMARY SUCCESSION
Soil starts to form as lichens and the forces of weather (wind and precipitation) and erosion help break down rocks into smaller pieces.
When lichens die, they decompose, adding small amounts of organic matter to the rock to make soil.

9. PRIMARY SUCCESSION
Simple plants like mosses and ferns can grow in the new soil.

10. PRIMARY SUCCESSION
The simple plants die, adding more organic material.
The soil layer thickens, and grasses, wildflowers, and other plants begin to take over

11. PRIMARY SUCCESSION
These plants die, and they add more nutrients to the soil. Shrubs and trees can now survive.

12. PRIMARY SUCCESSION
Insects, small birds, and mammals can now move in. The entire process of primary succession can take hundreds or even thousands of years.

13. PRIMARY SUCCESSION

15. SECONDARY SUCCESSION
Secondary succession is the recolonization of an area after an ecological disturbance has occurred, but the soil and some plants still remain.
This soil is vital because it contains all the nutrients that will support the future life.

16. SECONDARY SUCCESSION
Usually, fast-growing annual species flourish, which grow, reproduce, and die within a year.
Within a few years, grasses and non-woody perennials emerge. Shrubs soon follow, and trees ensue.

17. SECONDARY SUCCESSION

18. CLIMAX COMMUNITY
As the plants grow, they compete for light and space. This competition will allow only the most successful to survive.
Once animals join the community, there will eventually be no major environmental changes.

19. CLIMAX COMMUNITY
Once the community is stable, with an equilibrium between biotic and abiotic components, it has become a climax community.
This is the final stage of ecological succession.

20. CLIMAX COMMUNITY
The climax community is dependent on the soil, water and temperature.
It is dynamic, meaning that although stable, it is constantly changing with the climate. Examples include the grasses in prairies, or cacti in deserts.

21. Ecological Succession