IQWST foxes and rabbits model

globals
[
  time
  foxes-color
  rabbits-color
  grass-color
  dirt-color
  invasive-color
  rabbits-stride ;; how much a rabbi moves in each simulation step
  invaders-stride  ;; how much an invader moves in each simulation step
  foxes-stride ;;  how much a fox moves in each simulation step
  fox-size
  rabbit-reproduce-age
  invader-reproduce-age
  fox-reproduce-age
  rabbits-energy-gain-from-food
  foxes-energy-gain-from-rabbits
  foxes-energy-gain-from-invaders
  max-plant-energy
  max-rabbits-age
 ;; grass-delay
  min-reproduce-energy-rabbits ;; energy required for reproduction
  min-reproduce-energy-invaders  ;; energy required for reproduction
  min-reproduce-energy-foxes ;; energy required for reproduction
  invaded?
  max-foxes-age
  max-invaders-age
  max-rabbits-offspring
  max-foxes-offspring
  max-invaders-offspring
]

breed [ rabbits rabbit]
breed [ invaders invader]
breed [ foxes fox]

turtles-own [ energy current-age max-age female?]
patches-own [ fertile?  plant-energy ]

to setup
  ;; (for this model to work with NetLogo's new plotting features,
  ;; __clear-all-and-reset-ticks should be replaced with clear-all at
  ;; the beginning of your setup procedure and reset-ticks at the end
  ;; of the procedure.)
  clear-all
  set time 0
  set invaded? false
  set max-plant-energy 100
  set rabbits-stride 0.3
  set invaders-stride 0.3
  set foxes-stride 0.4
  ;;  a larger foxes-stride than rabbits-stride leads to scenarios where less foxes
  ;;  can keep a larger number of rabbitss in balance.
  set rabbit-reproduce-age 20
  set invader-reproduce-age 20
  set fox-reproduce-age 40
  set max-foxes-age 100
  set max-invaders-age 100
  set max-rabbits-age 100
  set rabbits-energy-gain-from-food 4
  set foxes-energy-gain-from-rabbits 25
  set foxes-energy-gain-from-invaders 25
  set min-reproduce-energy-rabbits 10
  set min-reproduce-energy-invaders 10
  set min-reproduce-energy-foxes 10
  set max-rabbits-offspring 3
  set max-invaders-offspring 3
  set max-foxes-offspring 2
  set fox-size 1
  set foxes-color  (red - 1)
  set rabbits-color (gray - 1)
  set invasive-color (blue - 3)
  set grass-color (green)
  set dirt-color (white)
  set-default-shape rabbits "rabbit"
  set-default-shape foxes "fox"
  set-default-shape invaders "mouse"
  add-starting-grass
  add-rabbits
  add-foxes
  do-plots
  reset-ticks
end 

to go
 if time >= 2500 [stop]
  ask rabbits [ rabbits-live reproduce-rabbits]
  ask foxes [ foxes-live reproduce-foxes]
  ask patches [grow-grass]   ;;only the fertile patches can grow grass

  do-plots  ;; plot populations
  set time time + 1
end 

to add-starting-grass
  ask patches [
      ifelse random 100 < percent-grass    ;;student sets the maximum number of fertile patches
    [
      set fertile? true
      set plant-energy (max-plant-energy - random max-plant-energy)
    ]
    [
      set fertile? false
      set plant-energy 0
    ]
    color-grass
  ]
end 

to add-rabbits
  create-rabbits initial-number-rabbits  ;; create the rabbits, then initialize their variables
  [
    set color rabbits-color
    set energy 20 + random 20 - random 20;;randomize starting energies
    set current-age 0  + random max-rabbits-age     ;;don't start out with everyone at the same age
    set max-age max-rabbits-age
    setxy random world-width random world-height
     ;;ifelse (random 2 = 0) [set female? true] [set female? false]
  ]
end 

to add-foxes
  create-foxes initial-number-foxes  ;; create the rabbits, then initialize their variables
  [
    set color foxes-color
    set energy 40 + random 40 - random 40 ;;randomize starting energies
    set current-age 0  + random max-foxes-age     ;;don't start out with everyone at the same age
    set max-age max-foxes-age
    set size fox-size
    setxy random world-width random world-height
   ;;  ifelse (random 2 = 0) [set female? true] [set female? false]
  ]
end 

to rabbits-live
    move-rabbits
    set energy energy - 1  ;; rabbitss lose energy as they move
    set current-age current-age + 1
    rabbits-eat-grass
    death
end 

to foxes-live
  move-foxes
  set energy energy - 1  ;; foxes lose energy as they move
  set current-age current-age + 1
  eat-prey
  death
end 

to move-rabbits  ;; turtle procedure
  rt random 50 - random 50
  fd rabbits-stride
end 

to move-invaders  ;; turtle procedure
  rt random 40 - random 40
  fd invaders-stride
end 

to move-foxes  ;; turtle procedure
  rt random 50 - random 50
  fd foxes-stride
end 

to rabbits-eat-grass  ;; rabbits procedure
  ;; if there is enough grass to eat at this patch, the rabbits eat it
  ;; and then gain energy from it.
  if plant-energy > rabbits-energy-gain-from-food  [
    ;; plants lose ten times as much energy as the rabbits gains (trophic level assumption)
    set plant-energy (plant-energy - (rabbits-energy-gain-from-food * 10))
    set energy energy + rabbits-energy-gain-from-food  ;; rabbits gain energy by eating
  ]
  ;; if plant-energy is negative, make it positive
  if plant-energy <=  rabbits-energy-gain-from-food  [set plant-energy 0]
end 

to eat-prey  ;; foxes procedure
    if (any? rabbits-here and not any? invaders-here)
        [ask one-of  rabbits-here  [die]
           set energy (energy + foxes-energy-gain-from-rabbits)
         ]
      if (any? invaders-here and not any? rabbits-here)
        [ask one-of  invaders-here  [die]
           set energy (energy + foxes-energy-gain-from-invaders)
         ]
      if (any? invaders-here and any? rabbits-here)
        [ifelse random 2 = 0   ;; 50/50 chance to eat an invader or a rabbit if both are on this patch
           [ask one-of  invaders-here  [die] set energy (energy + foxes-energy-gain-from-invaders)]
           [ask one-of  rabbits-here  [die] set energy (energy + foxes-energy-gain-from-rabbits)]
         ]
end 

to reproduce-rabbits  ;; rabbits procedure
  let number-offspring (random (max-rabbits-offspring + 1)) ;; set number of potential offpsring from 1 to (max-rabbits-offspring)
  if (energy > ((number-offspring + 1) * min-reproduce-energy-rabbits)  and current-age > rabbit-reproduce-age)
  [
    if random 2 = 1           ;;only half of the fertile rabbitss reproduce (gender)
    [
      set energy (energy - (number-offspring  * min-reproduce-energy-invaders))      ;;loose energy when reproducing --- given to children
      hatch number-offspring
      [
        set size 1
        set color rabbits-color
        set energy min-reproduce-energy-rabbits ;; split remaining half of energy amongst litter
        set current-age 0
       ;; ifelse (random 2 = 0) [set female? true] [set female? false]
        rt random 360 fd rabbits-stride
      ]    ;; hatch an offspring set it heading off in a a random direction and move it forward a step
    ]
  ]
end 

to reproduce-invaders  ;; rabbits procedure
  let number-offspring (random (max-invaders-offspring + 1)) ;; set number of potential offpsring from 1 to (max-invaders-offspring)
  if (energy > ((number-offspring + 1) *  min-reproduce-energy-invaders)  and current-age > invader-reproduce-age)
  [
    if random 2 = 1           ;;only half of the fertile invaders reproduce (gender)
    [
      set energy (energy - ( number-offspring * min-reproduce-energy-invaders))            ;;loose energy when reproducing --- given to children
      hatch number-offspring
      [
        set size 1
        set color invasive-color
        set energy min-reproduce-energy-invaders ;; split remaining half of energy amongst litter
        set current-age 0
       ;; ifelse (random 2 = 0) [set female? true] [set female? false]
        rt random 360 fd invaders-stride
      ]    ;; hatch an offspring set it heading off in a a random direction and move it forward a step
    ]
  ]
end 

to reproduce-foxes  ;; rabbits procedure
  let number-offspring (random (max-foxes-offspring + 1)) ;; set number of potential offpsring from 1 to (max-invaders-offspring)
  if (energy > ((number-offspring + 1) * min-reproduce-energy-foxes)  and current-age > fox-reproduce-age)
  [
    if random 2 = 1           ;;only half of the fertile rabbitss reproduce (gender)
    [
      set energy (energy - (number-offspring * min-reproduce-energy-foxes))           ;;loose energy when reproducing --- given to children
      hatch number-offspring
      [
        ;;set breed eggs
        set current-age 0
        set size fox-size
        set color foxes-color
        set energy min-reproduce-energy-foxes ;; split remaining half of energy amongst litter
        set current-age 0
       ;; ifelse (random 2 = 0) [set female? true] [set female? false]
        rt random 360 fd foxes-stride
      ]    ;; hatch an offspring set it heading off in a a random direction and move it forward a step
    ]
  ]
end 

to death  ;; turtle procedure
  ;; die when energy dips below zero (starvation), or get too old
  if (current-age > max-age) or (energy < 0)
  [ die ]
end 

to grow-grass  ;; patch procedure

  ;; fertile patches gain 1 energy unit per turn, up to a maximum max-plant-energy threshold
  if fertile?
     [set plant-energy (plant-energy + 1) if plant-energy > max-plant-energy [set plant-energy max-plant-energy]]

  if not fertile?
     [set plant-energy 0]
  if plant-energy < 0 [set plant-energy 0]
  color-grass
end 

to color-grass
  ifelse fertile? [
    ifelse plant-energy > 0
    ;; scale color of patch from whitish green for low energy (less foliage) to green - high energy (lots of foliage)
    [set pcolor (scale-color green plant-energy  (max-plant-energy * 2)  0)]
    [set pcolor dirt-color]
    ]
  [set pcolor dirt-color]
end 

to do-plots
    set-current-plot "populations"
    set-current-plot-pen "rabbits"
    plot count rabbits
 ;;   set-current-plot-pen "invaders"
;;    plot count invaders
    set-current-plot-pen "foxes"
    plot count foxes
    set-current-plot-pen "grass"
    plot (sum [plant-energy] of patches / max-plant-energy)
end