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Vegetation interspecific competition

Andrew Hofmeister
Common Timothy is an invasive grass species.  Alpine Timothy is the native grass species in Yellowstone.  I calculated the carrying capacity of the grasses by converting acres, square feet, pounds per square feet and seeds per pound.  There is a higher birth rate and lower death rate for the common timothy because the grass is taking over the area due to a lack of wildlife predators.


  • 5 years 2 months ago

Final Midterm Student version of A More Realistic Model of Isle Royale: Predator Prey Interactions

Andrew E Long
This model illustrates predator prey interactions using real-life data of wolf and moose populations on the Isle Royale.

We incorporate logistic growth into the moose dynamics, and we replace the death flow of the moose with a kill rate modeled from the kill rate data found on the Isle Royale website.

I start with these parameters:
Wolf Death Rate = 0.15
Wolf Birth Rate = 0.0187963
Moose Birth Rate = 0.4
Carrying Capacity = 2000
Initial Moose: 563
Initial Wolves: 20

I used RK-4 with step-size 0.1, from 1959 for 60 years.

The moose birth flow is logistic, MBR*M*(1-M/K)
Moose death flow is Kill Rate (in Moose/Year)
Wolf birth flow is WBR*Kill Rate (in Wolves/Year)
Wolf death flow is WDR*W

Environment Ecology Populations Midterm

  • 2 years 10 months ago