1. Coral Reef Succession

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

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

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

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

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

7. Mount St. Helens prior 1980

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

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

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

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

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

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

19. Ecological Succession on a Coral Reef The Big Island

20. 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