Camas-human-elk model

1 collaborator

WHAT IS IT?

Camas, humans, and elk (among many other more-than-human animals, plants, insects, and natural kinds like water) interact in camas prairies in the Pacific Northwest region of the United States. Camas is a disturbance-loving plant, meaning that it grows better when humans harvest responsibly and when elk graze the prairie, so long as elk populations are near and not over carrying capacity for the land. This is a model of camas-human-elk relationships in the prairie.The model should illustrate how camas is a disturbance-loving plant that actually grows more rapidly when humans and elk harvest, but only up to a certain point. After humans and/or elk begin to over-harvest, the system stops functioning as well and the camas population begins to die off.

HOW IT WORKS

Sliders control human, elk, and camas reproduction rates and initial population numbers. Sliders also control the likelihood that humans will harvest the camas or hunt the elk they meet. Humans eat both camas and elk. Elk eat camas, as well. Elk and humans will have instructions under To Go commands so that they move about randomly and consume or harvest camas as they find them.

HOW TO USE IT

Click setup and then go. Use the sliders to change the variables.

THINGS TO NOTICE

Notice in the graph that as the human population increases, the elk and camas population increase as well for a short time. As the human population increases past a certain point, the elk and camas populations both decline rapidly.

THINGS TO TRY

Try changing the sliders to see how the model might run differently. What happens when you decrease or increase the populations of various species? What happens if you make the humans more or less likely to hunt elk or havest camas?

EXTENDING THE MODEL

Try to alter to the code to make the elk actively avoid the humans in the prairie, which would be more accurate. Try to alter the code to make the humans engage in the prairie more sustainably.

NETLOGO FEATURES

I'm not sure that any of this code is particuarly interesting, but do notice that the ages at which the humans, elk, and camas are meant to die is a fairly accurate repsentation of the life expectancies.

RELATED MODELS

This model is related to many of the predator-prey models in the models library and the commons.

CREDITS AND REFERENCES

Referencing this model: McDaid-Morgan, N. (2019). NetLogo camas-elk-human model.

Comments and Questions

Nikki McDaid-Morgan

Referencing this model

To reference this model: McDaid-Morgan, N. (2019). NetLogo camas-elk-human model.

Posted over 6 years ago

Click to Run Model

breed [humans human]
breed [camas camass]
breed [elk elks]
camas-own [age]
humans-own [age]
elk-own [age]

To Setup
clear-all
  create-humans number-of-humans [
    set age age + 1
    set shape "person"
    set color  35
    set size 1.5
    move-to one-of patches
  ]

  create-elk number-of-elk [
  set age age + 1
    set shape "elk"
   set color 33
    set size 1.5
   move-to one-of patches
  ]

  create-camas number-of-camas [
   set age age + 0.5
    set shape "camas"
    set size 1.5
   set color 53
   move-to one-of patches
  ]



  ask patches [
    set pcolor 57]

reset-ticks
end 

to go

  if not any? camas [ stop]
  ask humans [
    set age age + 1
    right random 10
    left random 10
    forward 1
    if random-float 150 < human-reproduction [
      hatch-humans 1 [
        set age 0
        set color 35
        move-to one-of neighbors]
    ]


    if age > 80 [die]
    if any? camas-here [
      if random-float 100 < human-harvest [
        ask camas-here
        [die]
      ]
    ]

    if any? elk-here [
       if random-float 100 < human-hunt [
      ask elk-here [die]
    ]
   ]
  ]


  ask elk [
    set age age + 1
    right random 10
    left random 10
    forward 1
    if random-float 100 < elk-reproduction [
      hatch-elk 1 [
        set age 0
        set color 33
        move-to one-of neighbors]
    ]
    if age > 13 [die]
    if any? camas-here [
      ask camas-here [die]
    ]
  ]

  ask camas [
  set age age + 0.5
    if age > 5 [die]
    if random-float 100 < camas-reproduction [
    hatch-camas 1 [
      set color 53
        set age 0
        move-to one-of neighbors]
    ]
  ]
  tick
end

There is only one version of this model, created over 6 years ago by Nikki McDaid-Morgan.

Attached files

File	Type	Description	Last updated
Camas-human-elk model.png	preview	Preview for 'Camas-human-elk model'	over 6 years ago, by Nikki McDaid-Morgan	Download

This model does not have any ancestors.

This model does not have any descendants.

NetLogo