Silver Springs, Florida

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Silver Springs, Florida

• A five compartment model of energy flow in an
  ecosystem

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Structure and energy flow patterns of Silver
Springs
Odum, H. T. 1957. Trophic structure and
productivity of Silver Springs. Ecological
Monographs 2755-112.
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Diagram showing interactions and empirical steady
state quantities
Cox, G. W. 1996. Laboratory Manual of General
Ecology, 7th ed. Wm. C. Brown Publ.
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Equation Coefficients and State Variables pij and
Xi where for p, i source of energy and j
receiver of energy and for X, i trophic level

• 0 external environment
• 1 primary producer
• 2 herbivore
• 3 carnivore
• 4 top carnivore
• 5 decomposer
• 6 down-stream export
• 7 bread

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Model differential equations
Cox, G. W. 1996. Laboratory Manual of General
Ecology, 7th ed. Wm. C. Brown Publ.
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Equation Coefficients and State Variables pij and
Xi where for p, i source of energy and j
receiver of energy and for X, i trophic level

• 0 external environment
• 1 primary producer
• 2 herbivore
• 3 carnivore
• 4 top carnivore
• 5 decomposer
• 6 down-stream export
• 7 bread

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Empirically derived coefficients
Cox, G. W. 1996. Laboratory Manual of General
Ecology, 7th ed. Wm. C. Brown Publ
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Programming with Stella II

• Dynamic simulation software for systems modeling

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Stella II flow diagram
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Results of the simulation

• Predicting the behavior of Silver Springs under
  altered conditions
• numerical integration method Runge Kutta

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Model output - standard run
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Model run - primary production reduced
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Model output - primary production increased
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Model run - bread input eliminated
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Model run - bread input increased
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Model run - Herbivore consumption rate reduced
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Model run - Herbivore consumption rate increased
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Model run - top carnivore mortality increased
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Conclusions from Silver Springs

• Change in complex systems may not always be
  intuitive. The way we treat our environment may
  have unexpected outcomes.

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Thank You !