1. Ecosystem Connectivity
MARE 444
Dr. Turner

2. What is Connectivity
The ability to make and maintain a connection between two or more points in a telecommunications system
Based upon neural-network systems

3. Ecological Connectivity
Three major themes:
1) between reefs/islands/habitats
2) among habitats by juvenile and adult fishes and invertebrates
3) between habitats with respect to nutrients and other physio-chemical factors

4. Metapopulations

5. Source-Sink Dynamics Source Sink
– receives immigrants but does not contribute individuals to the metapopulation
– contributes disproportionately more individuals to the metapopulation
Source
Sink

6. Larval Connectivity
Larvae arriving at settlement habitats could have originated from a large set of spawning sites
Determination of spawning sites critical

7. Larval Connectivity
The extent to which populations of marine organisms are (reliant on externally supplied larvae)
or (self-replenishing) is scale dependent

8. Connectivity of marine populations: open or closed?
Dispersion
After 30 d
Antigua
Guadeloupe
Martinique
St. Lucia
Cowen et al.
Science 2000
Transport endpoints of 10,000 virtual larvae released from Barbados

9. Within 30 d larvae released over 1 km2 location spread over 106 km2
Transport endpoints: larval mortality 18% day (Z ~ 0.20)

10. Larval Connectivity
Dilution of original concentration by six orders of magnitude
When mortality is added the outcome is obvious…

11. Larval Connectivity
However...

12. Meanwhile, further offshore
What about coral reef fishes attempting to recruit back to natal reefs again prevailing current patterns?
Offshore flow
5 m offshore
55 m inshore
Inshore flow
Surface flows on western
side of island is offshore—
results in upwelling and onshore flow at m
Vertical distribution
of larvae; avoid surface
waters (offshore flow)
Swim at depth

13. Degree of control of
Late pelagic stages
Previous assumption:
swimming abilities negligible
Sustained swimming…
Will it modify dispersal?
Max durations h
~ km.

14. Ecological Connectivity
Ironically, however, few fishes that we associate with estuaries are in fact obligatory users (anadromous fishes are a notable exception)

15. Ecological Connectivity
To address this issue, we investigate "connectivity" in the life cycles of fishes
Connectivity here refers to the dependence of fish production and population dynamics on dispersal and migration among multiple habitats

16. Recently, natural tags, such as isotopes and elements within otoliths, have shown great promise as a means of determining connectivity among populations

17. Ecological Connectivity
Nearshore
Offshore
Juvenile
Nursery
Adult

18. Ecological Connectivity

19. How do we quantify connectivity?
Ecological Connectivity
How do we quantify connectivity?

21. Stable Isotopes

23. Connectivity Between Habitats

24. Connectivity of Habitats

25. Mangroves
Coral reef
Mangroves
Nursery