Coral Reef Succession

1. Coral Reef Succession

2. Ecological Succession The progressive change in the species composition of an ecosystem.

3. New Bare Substrate Colonizing Stage Successionist Stage Climax Stage Ecological Succession

4. 2 types of succession SECONDARY PRIMARY • Growth occurring after a disturbance changes a community without removing the soil • Growth occurs on newly exposed surfaces where no soil exists • Ex. Surfaces of volcanic eruptions

5. Primary Succession For example, new land created by a volcanic eruption is colonized by various living organisms

6. Secondary Succession Disturbances responsible can include cleared and plowed land, burned woodlands

7. Mount St. Helens prior 1980

8. Mount St. Helens Sep. 24, 1980 May 18, 1980

9. Mount St. Helens Fireweed 1980 after eruption 2004 2012

10. Succession after Volcanic Eruption What organisms would appear first? How do organisms arrive, i.e., methods for dispersal? Volcanic eruption creates sterile environment Hanauma Bay Tuff Ring (shield volcano)

11. Early species improve habitat. Ex. Early marine colonists provide a substrate conducive for settling of later arriving species. First arrivals take precedence. Competition for space, nutrients and light; allopathic chemicals. As resources become scarce due to depletion and competition, species capable of tolerating the lowest resource levels will survive. Mechanisms of Succession Facilitation Inhibition Tolerance

12. high reproductive output high growth rate short life span low competitive ability low reproductive output higher maternal investment per offspring high competitive ability long life span slow growth rate r & K Selected Species Pioneer species- 1st species to colonize a newly disturbed area r selected r & K refer to parameters in logistic growth equation Late successional species K selected

13. Ecological Succession on a Coral Reef

14. Successional Models and their Impacts (p.133) • Case 1: No Disturbance (Competitive Exclusion Model) • Case 2: Occasional Strong Disturbance (Intermediate Disturbance Model) • Case 3: Constant Strong Disturbance (Colonial Model)

15. Case 1: No Disturbance (Competitive Exclusion Model) • As the reef becomes complex, organisms • compete for space. • Dominant organism outcompetes other • species. • Occurs in stable environments. • Results in low species diversity. • Highly protected patch reefs within • lagoons or protected bays • Deeper water

16. Case 2: Occasional Strong Disturbance (Intermediate Disturbance Model) • Storms and hurricanes allow for other • species to move in • Dominant species would not be allowed to • reach competitive exclusion • After each disturbance have a recovery • period • Area of high diversity

17. Case 3: Constant Strong Disturbance (Colonial Model) • Constant exposure to disturbance • Shallow environment • High turnover of species • r-selected species

18. Case 3 Near reef crest Case 2 Reef slope beneath reef crest Reef Case 1 Deep reef slope

19. Ecological Succession on a Coral ReefThe Big Island

20. Ecological Succession on a Coral Reef

21. Ecological Succession on a Coral Reef

22. Ecological Succession on a Coral Reef

23. Ecological Succession on a Coral Reef

24. Ecological Succession on a Coral Reef

25. Ecological Succession on a Coral Reef

26. Ecological Succession on a Coral Reef

27. Successional Models and their Impacts

28. a) The slopes of a newly formed volcanic island b) Wetlands in Texas, following Hurricane Rita c) A receding glacier d) A dried up lake e) Primary succession would not occur on any of these. Primary succession would take place on all of the following EXCEPT:

29. QUESTION: Review A “K” selected species generally has all of the following characteristics EXCEPT: a) Large size b) Short-lived c) Good competitor d) Constant population size e) Slow population growth