Ecological Succession : (Important info in blue)

1. Communities in Transition Ecological Succession:(Important info in blue)

2. Ecological Succession • Ecological Succession – The replacement of one community by another until a climax community is reached • May take hundreds or thousands of years • Each new community makes it harder for the old communities to survive.

3. Ecological Succession • New environmental conditions allow one group of species in a community to replace other groups. • All communities change their structure and composition in response to changing environmental conditions. • During succession: • Pioneer species arrive first.

4. Ecological Succession • (Examples only – Write what will help you) • A forest hundreds of years old may have been a shallow lake thousands of years ago. • A dead tree falls and allow sunlight to reach the forest floor. Sunlight allows seeds to germinate. Wildflowers and shrubs grow. • Moss, shrubs, and small trees cover the concrete of an old city building.

5. Ecological Succession • Pioneer Species – The first organisms to colonize any newly available area and begin the process of ecological succession. • The pioneer organism will alter the environment so that a bigger and better organism can move in. • Climax Community – A final and stable community.

6. Climax Communities • A climax community can only be disrupted by a catastrophe. • After the catastrophe it will then rebuild itself back up again.

7. Types of Succession • Primary Succession – Succession that occurs on a surface where an ecosystem did not previously exist • Secondary Succession – Succession that occurs on a surface where an ecosystem had previously existed.

8. Primary Succession: Starting from Scratch

9. Lichens and mosses Exposed rocks Balsam fir, paper birch, and white spruce forest community Jack pine, black spruce, and aspen Heath mat Small herbs and shrubs Time Fig. 7-11, p. 156

10. Primary Succession • DEFINITION: Succession that occurs on a surface where an ecosystem did not previously exist • Examples: Bare rock, newly cooled lava, abandoned highway or parking lot • Takes a long time because there is no fertile soil to provide the nutrients needed to establish a plant community. • Begins when pioneer species arrive and attach themselves to bare rock. • Examples of pioneer species: Lichens and mosses

11. Lichens and mosses Exposed rocks Balsam fir, paper birch, and white spruce forest community Jack pine, black spruce, and aspen Heath mat Small herbs and shrubs Time Fig. 7-11, p. 156

12. Primary Succession

13. Primary Succession

15. Primary Succession: Lichens

16. Primary Succession: Lichens

17. Primary Succession: Lichens

18. Primary Succession: Lichens

19. Primary Succession: Lichens

20. Primary Succession

21. Primary Succession

22. Secondary Succession Starting Over With Some Help

23. Secondary Succession • Succession that occurs on a surface where an ecosystem had previously existed. • Examples: Abandoned farmland, burned/cut forests, heavily polluted streams, and land that has been flooded • New vegetation can usually germinate within a few weeks from seeds in the soil and those brought in from nearby plants by wind or by birds and other animals.

24. Secondary Succession • Secondary succession occurs in ecosystems that have been disturbed or disrupted by humans, animals, or natural processes.

25. Mature oak-hickory forest Young pine forest with developing understory of oak and hickory trees Shrubs and pine seedlings Perennial weeds and grasses Annual weeds Time Fig. 7-12, p. 157

26. Old-field Succession

27. Secondary Succession: Post-fire

28. Secondary Succession: Old Field

29. Secondary Succession: Post-Volcano