Overview

In class we went over four models that built from a very simple logistic model, adding maximum yield, then adding a variable carrying capacity and finally creating a refuge as part of the

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Model 1: Logistic growth

model 1- download the STELLA model

Model 2: Logistic growth with maximum yield

diagram 1 shows the model

diagram 2 shows the inteface that was used to simulate this in class.

model 2- download the STELLA model
logistic + harvest

Model 3: Adding variable carrying capacity

We used this model to show how harvesting enough to keep the population away from the carrying capacity lead to increased population growth rates throughout the entire season.

model 3- download the STELLA model
logistic-harvest-var

Model 4: Adding a refuge

This model has a carrying capacity that is variable and has a stretch of hard times. The idea is to be able to manage the popualtion as if you didn't know exactly when the bad section was.

In this model we adjusted the harvesting effort until the population crashed and then showed how adding a refuge could "buffer" the population and reduce the chances that the population crashes.

model 4- download the STELLA model
logistic-refuge