Systems analysis in the Marion Lake IBP Project.

Area of Science:

• Ecology
• Ecosystem Modeling
• Limnology

Background:

• The Marion Lake Project involved developing simulation models to track primary production through consumer components of the lake ecosystem.
• Two models were created, representing a simple compartment-flow system and a detailed population model for 24 animal species.

Purpose of the Study:

• To compare the effectiveness of different modeling approaches in representing lake ecosystem dynamics.
• To assess the predictive power of simple versus complex models for ecosystem responses to disturbance.

Main Methods:

• Development of a simple compartment-flow model.
• Development of a detailed population model incorporating density and individual growth for 24 species.
• Validation of both models against observed seasonal changes in lake ecosystem variables.

Main Results:

• Both models adequately described normal seasonal changes in ecosystem variables.
• The simpler compartment-flow model showed potential for better predictions regarding the system's response to disturbance.

Conclusions:

• The choice of model complexity impacts predictive accuracy for ecosystem disturbance.
• Initiating modeling efforts at the project's outset, rather than after extensive data collection, would have significantly improved modeling success.