395 4 months ago
This is the standard Lotke-Voltera model for a two stock predator prey system. It oscillates given the right settings.

Q: What is the carrying capacity (K) for this population?    300

Q: Carrying capacity (K) represents one equilibrium point in this model. Try to find another equilibrium point- that is, a point where the population neither grows nor declines. 100.

Max Fecundity, Min Mortality set to equal each other. Also, set Allele threshold to equal population value.

Q: is this equilibrium a stable equilibrium or an unstable equilibrium?

Unstable

Q: if you plot birth and death rates as a function of density in this model, can you identify the two equilibria?

Yes.

Q: Why do Allee effects generally spell bad news for w wildlife conservation and management?

"A population exhibiting a strong Allee effect will have a critical population size or density under which the population growth rate becomes negative. Therefore, when the population density or size hits a number below this threshold, the population will be destined for extinction without any further aid"(https://en.wikipedia.org/wiki/Allee_effect).

And just for fun, here is an article about the passenger pigeon and its possible “de-extinction”

Q: Do you support bringing back the passenger pigeon? Why or why not??

Yes, because they benefit other members of the food chain, particularly predators. One of the reasons they were hunted to extinction is because they were a tasty, cheap food for humans. They were also a Keystone species.

4b. Change the Age 1 mortality rate to 0.3. Run the simulation starting with 75 individuals, all in Age class 1. What happens? Is this a stochastic model? If not, why does it look like it has a random component?
No. It shows no randomness whether initial Age 1 population is 75 or 1000. Setting the time stamp to 0.1 eliminates the appearance of randomness.
4b. Change the Age 1 mortality rate to 0.3. Run the simulation starting with 75 individuals, all in Age class 1. What happens? Is this a stochastic model? If not, why does it look like it has a random component?
No. It shows no randomness whether initial Age 1 population is 75 or 1000. Setting the time stamp to 0.1 eliminates the appearance of randomness.
This is the modified Lotke-Voltera model for a two stock Human/ Nature system. Biocapacity model (land model) replaces exponential growth.
15 4 months ago
stochastic simulation of population with removal/harvest
10 months ago
Exercise 2, Problem 2b, Projection Matrix
4b. Change the Age 1 mortality rate to 0.3. Run the simulation starting with 75 individuals, all in Age class 1. What happens? Is this a stochastic model? If not, why does it look like it has a random component?
No. It shows no randomness whether initial Age 1 population is 75 or 1000. Setting the time stamp to 0.1 eliminates the appearance of randomness.
4b. Change the Age 1 mortality rate to 0.3. Run the simulation starting with 75 individuals, all in Age class 1. What happens? Is this a stochastic model? If not, why does it look like it has a random component?
No. It shows no randomness whether initial Age 1 population is 75 or 1000. Setting the time stamp to 0.1 eliminates the appearance of randomness.
This is a tandem modified Lotke-Voltera model for a Human/Disease/Nature system. Biocapacity model (land model) replaces exponential growth. Humans with Technology eradicate Disease.