Community Environment

globals [ rain-countdown
  rain-countdown-middle
  rain-countdown-greypatch
  sediment
  pollution
  relationship-energy
  run-number
  ready-persons-uphill-initial
  uphill-projects
  mud-patch-pollution
  hard-patch-pollution
  hard-patch-eroder


]

turtles-own [ energy
   stop-countdown

]

patches-own [eroded-land-to-grass-countdown
  eroded-land-to-hard-land-countdown
  hard-land-to-grass-countdown
]

breed [ready-persons ready-person]
breed [not-ready-persons not-ready-person]
breed [erosions erosion]
breed [flowers flower]
breed [erosion-middles erosion-middle]
breed [erosion-greypatchs erosion-greypatch]
breed [monarchs monarch]
breed [dragonflies dragonfly]
breed [mayflies mayfly]

to setup-keep
  clear-turtles
  clear-patches
  set run-number run-number + 1
  setup-world
end 

to setup-new
  ca
  set run-number 1
  setup-world
end 

to setup-world
  setup-ready-persons
  setup-not-ready-persons
  setup-erosions

  setup-dragonflies
  setup-mayflies
  reposition
  count-ready-persons-uphill




  set sediment 0
  set pollution 0
  set rain-countdown 500
  set rain-countdown-middle 500
  set relationship-energy 0
  set mud-patch-pollution 0
  set hard-patch-pollution 0
  set hard-patch-eroder 0
  set uphill-projects 0



ask patches [
    set eroded-land-to-grass-countdown eroded-land-to-grass-countdown + 750
    set eroded-land-to-hard-land-countdown eroded-land-to-hard-land-countdown + 1000
    set hard-land-to-grass-countdown hard-land-to-grass-countdown + 750]

  ask turtles [
    set stop-countdown 0
  ]

  ask patches [
    if pycor <= -15 ;-15 is the threshold between the blue patches and the green patches
    [set pcolor blue ] ;The blue patches represent a body of water.
    if pycor > -15
    [set pcolor green ] ;The green patches represent land that has vegetation with shallower root structure (like lawn) or have roots in the ground only part of the year (so as seasonal crops but no cover crops. Therefore, these conditions provide only modest filtration benefits.
     if (distancexy (0.3 * max-pycor) 0) < hard-surface * 2
  [ set pcolor grey ]

  ]
reset-ticks
end 

to setup-ready-persons
  create-turtles individual-readiness * 2  [
    setxy random-xcor random-ycor
    set size 2.15
    set breed ready-persons
    set shape "person"
    set color yellow
    set energy 40 ;assigning energy
  ]
end 

to setup-not-ready-persons
  create-turtles 10 - individual-readiness * 2 [
    setxy random-xcor random-ycor
    set size 2.15
    set breed not-ready-persons
    set shape "person"
    set color red

    set energy 5 ;assigning energy
  ]
end 

to reposition
  ask ready-persons
  [if ycor < -15
  [set ycor 0]
  ]
  ask ready-persons
  [if ycor > 18
    [set ycor 15]
  ]
  ask not-ready-persons
  [if ycor < -15
  [set ycor 0]
  ]
  ask not-ready-persons
  [if ycor > 18
    [set ycor 15]
  ]
end 

to setup-erosions ;sets up the erosion blue circles that begin uphill ;middle of the landscape erosion rainfall will begin after the first cycle
  ifelse downpours = false


  ;;if downpours are false/the else part is dry-spells are true   [these two next blocks of code are identical and must be left as two]

  ;


  [ ifelse dry-spells = false

    [create-turtles rainfall [    ;if dry-spells are false
      setxy random-xcor 20
      set size 0.5
      set color blue
      set heading 90
      set breed erosions
      set shape "circle"]]

    [create-turtles rainfall [    ;if dry spells are true (else)
      setxy random-xcor 20
      set size 0.5
      set color blue
      set heading 90
      set breed erosions
      set shape "circle"]]
  ]

  ;if downpours are false/the else part is dry-spells are true   [These two next blocks of code are identical and must be left as two]

  [ifelse dry-spells = false

    [create-turtles rainfall  [    ;if dry-spells are false
      setxy random-xcor 20
      set size 0.5
      set color blue
      set heading 90
      set breed erosions
      set shape "circle"]]

    [create-turtles rainfall  [    ;if dry spells are true (else)
      setxy random-xcor 20
      set size 0.5
      set color blue
      set heading 90
      set breed erosions
      set shape "circle"]]
  ]
end 

to setup-dragonflies
  create-turtles 3 [
    set xcor random-xcor
    set ycor -17
    set size 2.2
    set breed dragonflies
      set shape "dragonfly"]
end 

to setup-mayflies
  create-turtles 3 [
    set xcor random-xcor
    set ycor -17
    set size 2.2
    set breed mayflies
      set shape "mayfly"]
end 

to count-ready-persons-uphill
   set ready-persons-uphill-initial 0
  ask ready-persons [
    if pycor > 11 [
      set ready-persons-uphill-initial ready-persons-uphill-initial + 1
    ]]
end 

to go ;asks turtles to move and to take action. Asks patches to grow grass
  ask ready-persons [
  move
  plant-flowers-ready
  plant-flowers-ready-hardland
  cooperate
  collapse-community ;When water quality degrades to 8000, the water turns grey, and at 9000, all the people turn grey.



  ]

  ask not-ready-persons [
  move
  plant-flowers-not-ready
  plant-flowers-not-ready-hardland
  cooperate2
  collapse-community


  ]

  ask erosions [
    move-erosions
    erode-land
    stop-erosion
    pollute-water
    pickup-pollution
    birth-hardpatch-eroders
    birth-hardland-eroders

  ]

  ask erosion-middles [
    move-erosions
    erode-land
    stop-erosion
    pollute-water
    pickup-pollution
    birth-hardpatch-eroders

  ]


  ask patches [
    grow-grass-or-harden-land
    rebirth-erosions
    rebirth-erosion-middles
    birth-dragonflies
    birth-mayflies
    collapse-water
    hard-land-to-grass
  ]


  ask monarchs [
    wiggle
    death-monarch

  ]

  ask dragonflies [
    water-wiggle
    death-dragonfly

  ]

  ask mayflies [
    water-wiggle
    death-mayfly

  ]



  set rain-countdown rain-countdown - 1
  set rain-countdown-middle rain-countdown-middle - 1
  set rain-countdown-greypatch rain-countdown-greypatch - 1




;Constant subtraction rate to balance pollution as water flows over the green patches because these vegetated areas do contribute some to slowing/filtering water. There is no subtraction for going over a hard surface.
if hard-patch-pollution + mud-patch-pollution + pollution > 0 [
    set mud-patch-pollution mud-patch-pollution - .33]
if hard-patch-pollution + mud-patch-pollution + pollution < 0  [
    set mud-patch-pollution 0
    set hard-patch-pollution 0
    set pollution 0]
if sediment < 0  [
    set sediment 0]

  tick
end 

to move ;Move function for persons as well as the stop-countdown function to halt the model at 8500 ticks.

  ifelse stop-countdown > 8500

  [rt 0
  lt 0
  fd 0
  user-message (word "You have reached the end of this scenario!"
     "Click HALT to try another;"
      " then press setup-keep or setup-new."
)
    ]


  [rt 0.43 * community-collaboration * 2  ; Community-collaboration alters the angle of moevment, which narrows or expands persons' sphere of influence. w/.75 range at 3 allows about 1/2 the range of movement.
  lt 5

  if pycor = -15 ; turns people around when they touch the body of water
  [ fd 0
    set heading heading + 180
  ]

    if pycor = 19 ; turns people around when they move too to the top edge of the landscape; The world is coded to "wrap" right and left only, not top and bottom, because moving agents who would wrap at the top would end up in the water below.]
  [ fd 0
    set heading heading + 180
  ]
    fd 0.15

    set stop-countdown stop-countdown + 1]
end 

to move-erosions  ;move function for erosions

  ifelse pcolor = grey

  [set heading 180
    fd 0.3]


  [ifelse pcolor = 35.6

    [set heading 180
      fd 0.3]
;this is the movement of rain over normal green patches
    [fd 0.075
      right random 35
      left random 35

      if heading >= 270
      [set heading 180]

      if heading <= 90
      [set heading 180]]]
end 

to wiggle
  rt random 40
  lt random 40
  fd 0.1
end 

to water-wiggle
  rt random 8
  lt random 8

   if pycor >= -15 ; These next two units of movement code limit the water insects to the blue patches only.
  [ fd 0
   set ycor -16
    set heading heading + 180 ]

   if pycor = -20 ;
  [ fd 0
    set ycor -19
    set heading heading + 180 ]

    fd 0.01
end 

to grow-grass-or-harden-land ;countdown for regrowing grass

  ifelse dry-spells = false ;The else component of this function (the second unit of code below) is that dry-spells are true.
  [if pcolor = brown [
    ifelse eroded-land-to-grass-countdown <= 0
      [ set pcolor green
        set eroded-land-to-grass-countdown 750  ;Setting the regrowth of grass countdown to 750 ensures that this countdown is slower than that of the rain.
        set sediment sediment - 1
        set mud-patch-pollution mud-patch-pollution - .1] ;The green patches have vegetation with shallower root structure (like lawn) or have roots in the ground only part of the year (so as seasonal crops but no cover crops. Therefore, these conditions provide only modest filtration benefits.
      [ set eroded-land-to-grass-countdown eroded-land-to-grass-countdown - 1 ]]]


  [if pcolor = brown [
    ifelse eroded-land-to-hard-land-countdown <= 0
      [ set pcolor 35.6
        set eroded-land-to-hard-land-countdown 1000  ;
        set sediment sediment + 3     ; When runoff passes over hardened land, it cannot infiltrate and thus erodes and picks up pollutants faster (see next line of code).
        set mud-patch-pollution mud-patch-pollution + .2]
      [ set eroded-land-to-hard-land-countdown eroded-land-to-hard-land-countdown - 1]]]
end 

to hard-land-to-grass
if pcolor = 35.6 [
    ifelse hard-land-to-grass-countdown <= 0
    [ set pcolor green
      set hard-land-to-grass-countdown 750
      set sediment sediment - 3
      set mud-patch-pollution mud-patch-pollution - .1]
    [ set hard-land-to-grass-countdown hard-land-to-grass-countdown - 1]]
end 

to erode-land ;erosion function that the eroders use to turn the patches from green to brown and adds sediment when land is hardened
 if pcolor = green [
    set pcolor brown
    set sediment sediment + 1
  ]

  if pcolor = 35.6 [
    set sediment sediment + 2]
end 

to plant-flowers-ready ;For a "ready" person to plant a flower, it takes 20 units of energy, and planting can be done on eroded land only.
  if energy >= 20 [
    if pcolor = brown [ ;If so, it then asks if they are on a brown patch,
      set pcolor 53  ;If so, it sets the patch dark green and subtracts 20 energy. The green patch is the signal that this patch has a flower agent on it, thus allowing the stop-erosion function included below.]
      set energy energy - 20
      set sediment sediment - 1.2
      set mud-patch-pollution mud-patch-pollution - 2 ; see plant-flowers-ready2 for note
     if pxcor < -11 [
        set uphill-projects uphill-projects + 1]
      hatch 1 [
        set breed flowers
        set shape "flower"
        set size 1.9
        set color 127

  ]]]
  if energy >= 61 [ ;caps amount of energy that a person can have, which is important to avoid count going too high when agents occasionally get stuck together
  set energy 60
  ]
end 

to plant-flowers-ready-hardland ;For a "ready" person to plant a flower on hardened soil, it takes 30 units of energy, and planting can be done on eroded land only.
  if energy >= 30 [
    if pcolor = 35.6 [ ;if so, it then asks if they are on a light-brown hardland patch,
      set pcolor 53  ;if so, it sets the patch dark green and subtracts 20 energy
      set energy energy - 30
      set sediment sediment - 3
      set mud-patch-pollution mud-patch-pollution - 2 ; see plant-flowers-ready2 for note
     if pxcor < -11 [
        set uphill-projects uphill-projects + 1]
      hatch 1 [
        set breed flowers
        set shape "flower"
        set size 1.9
        set color 127

  ]]]
  if energy >= 61 [ ;caps amount of energy that a person can have, which is important to avoid count going too high when agents occasionally get stuck together
  set energy 60
  ]
end 

to plant-flowers-not-ready  ; This function is for persons who were not ready but who have become "now ready."
  if energy >= 40 [
    if pcolor = brown [ ;if so, it then asks if they are on a light-brown hardland patch,
      set pcolor 53  ;if so, it sets the patch dark green and subtracts 40 energy
      set energy energy - 40
      set sediment sediment - 1.2
      set mud-patch-pollution mud-patch-pollution - 2 ; the value for the perennial planting is much higher when it stops erosion
      set shape "person now ready"
      if pxcor < -11 [
        set uphill-projects uphill-projects + 1 ]
      hatch 1 [
        set breed flowers
        set shape "flower"
        set size 1.9
        set color 127

  ]]]
  if energy >= 61 [
  set energy 60
  ]
end 

to plant-flowers-not-ready-hardland   ;This function is for persons who were not ready but who have become "now ready." For a "now-ready" person to plant a flower on hardened soil, it takes 55 units of energy, and planting can be done on eroded land only
  if energy >= 55 [
    if pcolor = 35.6 [ ;if so, it then asks if they are on a light brown hardland patch,
      set pcolor 53  ;if so, it sets the patch dark green and subtracts 40 energy
      set energy energy - 55
      set sediment sediment - 3
      set mud-patch-pollution mud-patch-pollution - 2 ; the value for the perennial planting is much higher when it stops erosion
      set shape "person now ready"
      if pxcor < -11 [
        set uphill-projects uphill-projects + 1 ]
      hatch 1 [
        set breed flowers
        set shape "flower"
        set size 1.9
        set color 127

  ]]]
  if energy >= 61 [
  set energy 60
  ]
end 

to cooperate ;Allows ready persons to give other persons energy when they interact directly with (cooperate) each other. Ready persons give and receive more energy than not-ready persons.
  ask not-ready-persons in-radius 0.9 [
      set energy energy + 5
      fd 0
      set heading heading + 180
      set relationship-energy relationship-energy + 1
    move
  ]
  ask other ready-persons in-radius 0.9 [
      set energy energy + 30
      fd 0
      set heading heading + 45
      set relationship-energy relationship-energy + 10
    move
]
end 

to cooperate2 ;Allows not-ready persons to give other persons energy when they interact directly (cooperate) with each other. Not-ready persons give and receive less energy than ready persons.

  ask ready-persons in-radius 0.9 [
      set energy energy + 5
      fd 0
      set heading heading + 145
      set relationship-energy relationship-energy + 5
    move
]
  ask other not-ready-persons in-radius 0.9 [
      set energy energy + 1
      fd 0
      set heading heading + 180
      set relationship-energy relationship-energy + 1
    move
]
end 

to stop-erosion
if pcolor = 53 [
 set sediment sediment - 1.2 ; perennial plantings are much more effective than grass; need more precise value
 set mud-patch-pollution mud-patch-pollution - 3.5
  die
]
end 

to rebirth-erosions

   if rain-countdown <= 0 [

  ifelse dry-spells = false
  ;dry spells = off
  [if count flowers > sediment [
      if count flowers < 225 [
      sprout 1 [  ;
         set breed monarchs
         set size 1.5
         set shape "monarch"
         set color 25
         set energy 40 ;To indicate that pollinators support ecosystem health, each monarch plants 2 flowers when it is "sprouted."
          setxy random-xcor random-ycor]]]]

  ;dry spells = on
    [if count flowers > 90 [
      if count flowers < 225 [
      sprout 1 [  ;
         set breed monarchs
         set size 1.5
         set shape "monarch"
         set color 25
         set energy 40 ;To indicate that pollinators support ecosystem health, each monarch plants 2 flowers when it is "sprouted."
          setxy random-xcor random-ycor]]]]


  ifelse downpours = false


  ;if downpours are false
  ;change the beginning to just depend on downpours with one ifelse statement and use the ifelse statements here to change the middle erosions code


  [ ifelse dry-spells = false

     ;if = false
     ;dowpours OFF
     ;dry-spells OFF

    [sprout rainfall [
         set breed erosions
         set shape "circle"
         set color blue
         set size 0.5
         setxy random-xcor 20]
         set rain-countdown 500

      ]

      ;else = true
      ;dowpours OFF
      ;dry-spells ON

        [if rainfall = 5 [
          sprout rainfall  [
         set breed erosions
         set shape "circle"
         set color blue
         set size 0.5
         setxy random-xcor 20
         set rain-countdown 750]]
        if rainfall = 4 [
          sprout rainfall  [
         set breed erosions
         set shape "circle"
         set color blue
         set size 0.5
         setxy random-xcor 20
         set rain-countdown 750]]
        if rainfall = 3 [
          sprout rainfall  [
         set breed erosions
         set shape "circle"
         set color blue
         set size 0.5
         setxy random-xcor 20
         set rain-countdown 750]]
        if rainfall = 2 [
          sprout rainfall  [
         set breed erosions
         set shape "circle"
         set color blue
         set size 0.5
         setxy random-xcor 20
         set rain-countdown 750]]
        if rainfall = 1 [
          sprout rainfall  [
         set breed erosions
         set shape "circle"
         set color blue
         set size 0.5
         setxy random-xcor 20
         set rain-countdown 750]]
          ]]



  ;if downpours are true  (else)
    ;downpours ON
    ;dry-spells OFF


  [ifelse dry-spells = false

    [sprout (rainfall * random 3) [
         set breed erosions
         set shape "circle"
         set color blue
         set size 0.5
         setxy random-xcor 20]
        set rain-countdown 250 ]

      ;downpours ON
      ;dry-spells ON

    [if rainfall = 5 [
          sprout rainfall * random 3  [
         set breed erosions
         set shape "circle"
         set color blue
         set size 0.5
         setxy random-xcor 20
         set rain-countdown 750 ]]
        if rainfall = 4 [
          sprout rainfall * random 3 [
         set breed erosions
         set shape "circle"
         set color blue
         set size 0.5
         setxy random-xcor 20
         set rain-countdown 750 ]]
        if rainfall = 3 [
          sprout rainfall * random 3  [
         set breed erosions
         set shape "circle"
         set color blue
         set size 0.5
         setxy random-xcor 20
         set rain-countdown 750 ]]
        if rainfall = 2 [
          sprout rainfall * random 3  [
         set breed erosions
         set shape "circle"
         set color blue
         set size 0.5
         setxy random-xcor 20
         set rain-countdown 750 ]]
        if rainfall = 1 [
          sprout rainfall * random 3  [
         set breed erosions
         set shape "circle"
         set color blue
         set size 0.5
         setxy random-xcor 20
         set rain-countdown 750]]
          ]
  ]]
end 

to rebirth-erosion-middles
  if rain-countdown-middle <= 0 [


    ifelse downpours = false

    ;downpours OFF
    ;dry-spells OFF

  [ ifelse dry-spells = false

    [sprout rainfall [
        set breed erosion-middles
         set shape "circle"
         set color blue
         set size 0.5
         set xcor random-xcor
         set ycor random-ycor
        set rain-countdown-middle 500]]

      ;downpours OFF
      ;dry-spells ON

        [if rainfall = 5 [
          sprout rainfall  [
         set breed erosion-middles
         set shape "circle"
         set color blue
         set size 0.5
         set xcor random-xcor
         set ycor random-ycor
         set rain-countdown-middle 750 ]]
        if rainfall = 4 [
          sprout rainfall  [
         set breed erosion-middles
         set shape "circle"
         set color blue
         set size 0.5
         set xcor random-xcor
         set ycor random-ycor
         set rain-countdown-middle 750 ]]
        if rainfall = 3 [
          sprout rainfall  [
         set breed erosion-middles
         set shape "circle"
         set color blue
         set size 0.5
         set xcor random-xcor
         set ycor random-ycor
         set rain-countdown-middle 750 ]]
        if rainfall = 2 [
          sprout rainfall  [
         set breed erosion-middles
         set shape "circle"
         set color blue
         set size 0.5
         set xcor random-xcor
         set ycor random-ycor
         set rain-countdown-middle 750 ]]
        if rainfall = 1 [
          sprout rainfall  [
         set breed erosion-middles
         set shape "circle"
         set color blue
         set size 0.5
         set xcor random-xcor
         set ycor random-ycor
         set rain-countdown-middle 750 ]]
          ]
    ]



  ;if downpours are true  (else)

    ;downpours ON
    ;dry-spells OFF

  [ifelse dry-spells = false

    [sprout (rainfall * random 3) [
          set breed erosion-middles
         set shape "circle"
         set color blue
         set size 0.5
         set xcor random-xcor
         set ycor random-ycor
        set rain-countdown-middle 250]]

      ;downpours ON
      ;dry-spells ON

    [if rainfall = 5 [
         sprout rainfall * random 3 [
         set breed erosion-middles
         set shape "circle"
         set color blue
         set size 0.5
         set xcor random-xcor
         set ycor random-ycor
         set rain-countdown-middle 750]]
        if rainfall = 4 [
          sprout rainfall * random 3 [
         set breed erosion-middles
         set shape "circle"
         set color blue
         set size 0.5
         set xcor random-xcor
         set ycor random-ycor
         set rain-countdown-middle 750]]
        if rainfall = 3 [
          sprout rainfall * random 3 [
         set breed erosion-middles
         set shape "circle"
         set color blue
         set size 0.5
         set xcor random-xcor
         set ycor random-ycor
         set rain-countdown-middle 750]]
        if rainfall = 2 [
          sprout rainfall * random 3 [
         set breed erosion-middles
         set shape "circle"
         set color blue
         set size 0.5
         set xcor random-xcor
         set ycor random-ycor
         set rain-countdown-middle 750]]
        if rainfall = 1 [
          sprout rainfall * random 3 [
         set breed erosion-middles
         set shape "circle"
         set color blue
         set size 0.5
         set xcor random-xcor
         set ycor random-ycor
         set rain-countdown-middle 750]]
          ]
  ]
  ]
end 

to birth-mayflies
  if count mayflies < 3 [
  if  mud-patch-pollution + hard-patch-pollution + pollution <= 350 [
    sprout 3 [  ;          brings back mayflies when water pollution improves
   set xcor 17
   set ycor random-ycor
   set size 2.2
   set breed mayflies
   set shape "mayfly"]
  ]]
end 

to birth-dragonflies
  if count dragonflies < 3 [
  if  mud-patch-pollution + hard-patch-pollution + pollution <= 750 [
    sprout 3 [  ;          brings back dragonflies when water pollution improves
    set xcor 17
    set ycor random-ycor
    set size 2.2
    set breed dragonflies
  set shape "dragonfly"]
  ]]
end 

to pickup-pollution ; changes the amount of pollution picked up, depending on whether the surface is eroded soil, hard surface, or dry/hardened land.
  if pcolor = brown [
    set mud-patch-pollution mud-patch-pollution + 0.17 ]
  if pcolor = grey [
    set hard-patch-pollution hard-patch-pollution + 2.5 ]; Runoff over pavement is 15-20 times more than over such vegetated surfaces as traditional lawn.
  if pcolor = 35.6 [
  set hard-patch-pollution hard-patch-pollution + 3.5 ]
  if count flowers > 70 [
    set pollution pollution - .1] ;This subtraction included to acknowledge that only 140 flowers are needed to allow significant improvement in water quality/reduce runoff. According to the Prairie Strips project, putting on 10% of agricultural land in prairie strips offers dramatic reduction.
end 

to pollute-water
  if pcolor = blue [
    set pollution pollution + .18
    die]
end 

to birth-hardpatch-eroders ;spawns larger-sized eroder on hard patch to show lack of filtration on hard patch
  if dry-spells = false [
  if pcolor = grey [
    set size 1.5
  ]
  if pycor <= -15 [
    die ]
  ]

  if dry-spells = true [
  if pcolor = grey [
    set size 1.5
  ]
  if patch-ahead 1 = brown [
      set size 1.5
  ]
  if pycor <= -15 [
      die ]
  ]
end 

to birth-hardland-eroders
 if dry-spells = false [
  if pcolor = 35.6 [
    set size 1.0
  ]
  if pycor <= -15 [
    die ]
  ]

  if dry-spells = true [
  if pcolor = 35.6 [
    set size 1.0
  ]
  if patch-ahead 1 = brown [
      set size 1.0
  ]
  if pycor <= -15 [
      die ]
  ]
end 

to death-monarch
  if mud-patch-pollution + hard-patch-pollution + pollution >= 9000 [ ;Monarchs die once the water has collapsed.
    die
  ]
end 

to death-mayfly ;Mayflies will die before dragonflies because mayflies have a low Pollution Tolerance Value
  if mud-patch-pollution + hard-patch-pollution + pollution > 300 [ ;Threshold is higher for rebirth because ecosystem needs to improve beyond the level when this species first died off.]
    die
  ]
end 

to death-dragonfly ;Dragonflies survive longer than mayflies because dragonflies have a higher Pollution Tolerance Value.
  if mud-patch-pollution + hard-patch-pollution + pollution  > 700 [ ;Threshold is higher for rebirth because ecosystem needs to improve beyond the level when this species first died off.] flushed out
    die
  ]
end 

to collapse-community
  if mud-patch-pollution + hard-patch-pollution + pollution >= 9000 [
    set color 3
    set shape "person"
  ]
end 

to collapse-water
  if mud-patch-pollution + hard-patch-pollution + pollution >= 8000 [
    if pycor <= -15 [
      set pcolor 3
  ]]
end