1. Stephenie Lazarus Brittany Lewis Amelia Clapp
The Effect of Mangrove Forest Depletion on Biodiversity in Southern Florida
Stephenie Lazarus
Brittany Lewis
Amelia Clapp

2. Outline Background Hypothesis Method Analysis Discussion Implications
Solutions
Conclusion

3. Background
The Mangrove Problem
The planet has lost 35% of its mangrove forests over the last twenty years.
The rate of loss of mangroves each year tops the loss of the rainforest at 2.1%
At the current rate of destruction all of the world’s mangroves will disappear in 50 years (Wells, 2006)

4. World Distribution of Mangroves
Background
World Distribution of Mangroves
(“Coastal and Marine Habitats,” 2005)

5. Reasons for Mangrove Depletion Costal development of mangrove forest
Background
Reasons for Mangrove Depletion
Natural and unnatural factors
Recent tsunami activity in south-east Asia
Ongoing human
coastal
development (Stone,
Richard, 2006).
Costal development of mangrove forest

6. The American Alligator
Background
The American Alligator
‘Alligator holes’
Estimated 1,000,000 in Florida
Alligator mississippiensis
Keystone species of mangrove forests
(Mazzotti, 2006)

7. Hypothesis
“Current natural and anthropogenic factors will deplete the mangrove forests and biodiversity of Southern Florida due to the elimination of the keystone species”

8. Method
Data Used
1 acre= 4, m^2
acres of Mangroves exist in Florida (FMRI, 2006)
Net primary production (NPP) of swamps and marshes = 9000 k cal/ m2/yr (Kling, 2006) = k cal/ acre/yr
Rate of mangrove loss= 2.1% (Wells, 2006)
Average plant efficiency= 35% (Kling, 2006)
Average American Alligator per km^2= (Mazzotti, 2006) = alligators/acre

9. Procedure to Test Hypothesis
Method
Procedure to Test Hypothesis
Construct Stella Models from given data
Determine future amount of Florida mangrove forest coverage
Determine future population of American Alligator in Florida
Determine whether models support the loss of mangroves coverage and elimination of American Alligator population

10. Projected Mangrove Forest Acreage Mangrove Acreage Stella Model
Analysis
Projected Mangrove Forest Acreage
Mangrove Acreage Stella Model

11. Projected Mangrove Forest Acreage
Analysis
Projected Mangrove Forest Acreage

12. American Alligator Population Model
Analysis
American Alligator Population Model
Assumptions
Alligator population only effected by habitat depletion (birth rate = death rate)
Alligators require mangrove acreage to live ( alligators can live in one acre of mangroves)
3211 American Alligators exist in the 469,000 acres mangroves analyzed
Because alligators are the keystone species of the southern Florida mangrove ecosystem the elimination of alligators will cause the extinction of other species and the decline of biodiversity

13. American Alligator Population Model
Analysis
American Alligator Population Model

14. American Alligator Population Model
Analysis
American Alligator Population Model
Projected American Alligator Population with Decline of Mangrove Forests

15. Projected Mangrove Forest Acreage
Discussion
Projected Mangrove Forest Acreage
Mangrove acreage halved by 2009
Acreage so minimal significant re-growth almost impossible
Mangrove acreage crash by 2032

16. Discussion
Projected American Alligator Population with Decline of Mangrove Forests
2030 mangrove acreage dips below 2000
Alligator population levels off at 218

17. Effect Mangrove Forest Acreage on Biodiversity
Discussion
Effect Mangrove Forest Acreage on Biodiversity
If trends continue the mangrove cover in southern Florida will be depleted beyond natural rebound ability
This loss of habitat results in an immense reduction of the American Alligator
The reduction of the American Alligator will cause the collapse of biodiversity in the southern Florida mangrove ecosystem (loss of ‘alligator holes’ = loss of habitat)

18. Implications
The loss of mangroves in southern Florida would have a negative effect on both the sport and commercial fishing industries since many fish either live in or use the mangrove forest as a nursery.
Natural buffering capacity of mangroves will disappear resulting in loss of protection from natural disasters
Numerous endangered/ threatened species currently relying on mangroves will likely go extinct
Ecotourism would decline resulting in a loss of income in the economy of southern Florida

19. Collect and plant propagules Re-growth usually quick
Solutions
Mangrove Propagule
Collect and plant propagules
Re-growth usually quick
Rehabilitated mangroves lack the biodiversity they once had (Wells, 2006)
Human conservation and education efforts (prevention is better than compensation)
Currently many organizations implement mapping and monitoring programs (Vaiphasa, Skidmore, and de Boer, 2006)

20. Recap Mangrove forests in southern Florida projected to crash by 2032
Conclusion
Recap
Mangrove forests in southern Florida projected to crash by 2032
Loss of mangrove acreage will result in the population crash of the keystone species in the southern Florida ecosystem
A loss of the keystone species results in the loss of biodiversity
Our analysis affirms our hypothesis

21. Conclusion
Take Home Message
“Southern Florida’s Mangrove ecosystem is in serious danger, but steps to preserve these mangroves still can be taken!”