Budworm population dynamics

Model : budworm1
Simile version : 3.1+
Date added : 2003-06-20
Keywords : Insects ; Budworm ; Population dynamics ; Pests ;

Description

This is a simple, two-compartment model of the interaction between a spruce budworm population and the forest resource (foliage biomass) that it depends upon. As the budworm population expands, it tends to eat out the foliage, leading to a population crash and the eventual recovery of the forest.

Files

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budworm1.sml

Diagram

Equations

Compartments:
  forest:       initial value = 1
  budworm:      initial value = 10

Flows:
  ageing =      (if forest<4 then 0.02 else 0)
  regression =  (if budworm>300 then forest-1 else 0)
  recruitment = forest*graph(0,400,400,5,0,400,1,21,points(292,315,346,346,328,311,302,301,301,308,318,327,332,339,345,346,348,352,352,352,353),budworm)*budworm where[budworm=budworm,forest=forest]
  death =       budworm

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