1. Changes in Ecosystems: Ecological Succession

2. Definition: Natural, gradual changes in the types of species that live in an area; can be primary or secondary The gradual replacement of one plant community by another through natural processes over time

3. Primary Succession Begins in a place without any soil –Sides of volcanoes –Landslides –Flooding Starts with the arrival of living things such as lichens that do not need soil to survive Called PIONEER SPECIES

4. Volcanic activity

5. Rock slide I

6. Pioneer_Lichen

7. Primary Succession Soil starts to form as lichens and the forces of weather 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

8. Rock slide III

9. http://www.life.uiuc.edu

10. Primary Succession Simple plants like mosses and ferns can grow in the new soil http://uisstc.georgetow n.edu http://www.uncw.edu

11. Primary Succession The simple plants die, adding more organic material The soil layer thickens, and grasses, wildflowers, and other plants begin to take over http://www.cwrl.utexas.edu

12. Primary Succession These plants die, and they add more nutrients to the soil Shrubs and tress can survive now http://www.rowan.edu

13. Primary Succession Insects, small birds, and mammals have begun to move in What was once bare rock now supports a variety of life http://p2-raw.greenpeace.org

14. http://www.geo.arizona.edu

15. http://www.ux1.eiu.edu

16. Climax Community A stable group of plants and animals that is the end result of the succession process Does not always mean big trees –Grasses in prairies –Cacti in deserts

17. A coniferous forest- climax

18. A rainforest forest- climax

19. A cold desert - climax

20. Secondary Succession Begins in a place that already has soil and was once the home of living organisms Occurs faster and has different pioneer species than primary succession Example: after forest fires

21. Fire

22. A burned forest

23. Secondary Succession Occurs where an existing community has been cleared by some disturbance

24. Secondary succession

25. Man made climax

26. What are the consequence of recurrent Hill fires in HK

27. Grassy hills in HK-Lantau

28. Simplifying the Ecosystem_Monoculture

29. Simplifying the Ecosystem_deforestation

30. Simplifying the Ecosystem_ pollution