2. Funded By NATO

3. Oyster reefs are complex ecological systems because they:

4. Are open systems Are composed of multiple interacting components Are hierarchically structured Exhibit dissipative structures Filter feeders Detritus Micro- biota Preda- tors Deposit feeders Meio- fauna

5. Are far from equilibrium Free Energy Reaction Coordinate Equilibrium Death Life Steady State Excessive disorder, too much change Excessive order, rigid, no change Turbidity Human Impact Benthic or Pelagic Food Web Alternate Equilibria Benthic Pelagic Exhibit alternate equilibria

6. Demonstrate feedback REEF Clump Larvae and spat Display evidence of self-organization Show emergence

7. Connections or flows are non-linear 50% Power Efficiency max R =  Wt 0.75 R = Respiration Rate Wt = body weight 10 1.0 5 0.0011.0 Relationships may exist across multiple scales Systems evolve for high production (max. power principle) and are highly optimized for tolerance (HOT)

8. HOT Systems Are robust, yet fragile Unlike SOC systems where massive fluctuations occur as a result of the natural system dynamics, HOT systems are hypersensitive to new environmental perturbations that were not part of the systems evolutionary history (catastrophic or anthropogenic) HOT systems demand a change in research strategy from confirming negative effects to determining if a system can survive proposed changes (robust enough) before they happen

9. The preceding attributes support the contention that oyster reefs are complex systems, that is, they are composed of a large number of interacting components that are observable across many scales and their dynamics are non-linear (causes are not proportional to consequences). Thus, such systems are often unpredictable. In this context, how does complexity influence oyster reef restoration?

10. Restoration: A complex systems view

11. Ecological Restoration Restoration attempts to return an ecosystem to its historic trajectory.

12. Traditional Approach To Restoration Assumes the organisms via succession will rebuild the original system But, first, the historical environmental or disturbance regimes must be reestablished

13. Oyster Density E1E1 E2E2 Environment Oysters No Oysters Traditional - Environmental Conditions Changed to Historical Levels Recovery Collapse Recovery and collapse trajectories are the same or very similar

14. But, sometimes the recovery is unpredictable and the original state is not achieved. The system shifts to an alternate state.

15. System state S1S1 S2S2 E1E1 E2E2 Environment Oysters Plankton Complex Systems Approach : Alternate States

16. The Complex Systems Approach to Restoration Assumes the reference or pristine system used for comparison is a complex system. Considers the degraded system as an alternate state that is very different from the natural or pristine state. Recognizes that the trajectory to degradation is often different from the pathway to recovery, usually due to ecological constraints that cause internal feedbacks.

17. Focus is on identifying the ecological constraints and feedbacks, using experiments (including simulation models), comparative synthetic analyses, scenario analysis, etc. Determine if the system is robust to potential changes. Finally, the constraining feedbacks are disrupted and the system is engineered toward the desired state.

18. System state S1S1 S2S2 E1E1 E2E2 Environment Oysters Plankton Collapse Engineered – Oysters added Historical environment not restored, system contiinues to collapse

19. System state S1S1 S2S2 E1E1 E2E2 Environment Oysters Plankton Collapse Engineered - Feedbacks identified and manipulated Recovery Historical environment restored and system returns by different trajectory to original state

20. System state S1S1 S2S2 E1E1 E2E2 Environment Oysters Plankton Engineered - Feedbacks identified and manipulated Collapse Recovery Feedbacks Understanding of feedback controls allows near direct reestablishment of original state

21. Features of complex ecological systems that make them a management challenge Feedback vs. Direct Controls Non-linear vs. Linear Connections HOT vs. SOC

22. All of which leads to Surprise

23. Very Large LINKS

24. Thieving LINKS

25. Suggests a research strategy that: Determines the control mechanisms Encourages scenario development no matter how extreme (think outside of the box approach) Promotes the building and use of simulation models as experimental test beds Is long term in scope, as the environment is constantly changing

26. It’s A Non-linear World! Be Prepared. Plan Ahead.

28. NOTES

29. Restoration Evaluation Direct comparison of selected parameters are determined or measured with regard to a reference site. Attribute analysis compares via modeling the attributes of the restored and reference systems. Trajectory analysis interprets time series of comparative data to determine trends.

30. Recovery and Restoration An ecosystem has recovered – and is restored – when it contains sufficient biotic and abiotic resources to continue its development without further assistance or subsidy. It will sustain itself structurally and functionally. It will also demonstrate resilience to normal ranges of environmental stress and disturbance.

31. Attributes of Restored Ecosystems Contains characteristic assemblage of species with regard to the reference system. Consist of indigenous species to the greatest practicable extent. All necessary functional groups are represented. The physical environment is capable of sustaining reproducing populations.

32. The restored system functions normally/ It is suitably integrated into the next larger ecological scale. Potential threats to its health and integrity have been essentially eliminated. Is resilient to normal environmental conditions. The ecosystem is self-sustaining to the same degree as the reference system.