Ecological modelling
with Simile

Robert Muetzelfeldt
Jasper Taylor
Jonathan Massheder

www.simulistics.com
Feb 2006

Lecture 3
Population submodels

Individual-based modelling involves representing each individual separately, rather than using one or several state variables to represent the aggregate population.
If you have a fixed number of individuals, you can use a fixed-membership multiple-instance submodel (Lecture 2).
If you have a varying number of individuals, you need to use a population submodel.

When do we need to use a population submodel?

Fixed population size

x = rand(0,80)
y = rand(0,100)

gr = rand(1,3)

growth = gr*(1-size/25)

size = rand(1,5)

total = sum([size])

Fixed population
size: results

r = rand_var(0,1)<0.3

m = 0.2

create = 10

one = 1

N = sum({one})

Simple dynamic
population

Age-class
population

age = time(1)-init_time(1)

Size-class
population

Simple density-dependence

N = sum({one})

r = 0.5*(1-N/K)

Interaction with food

Male and female individuals

Animal movement

Animal movement

Ecological modelling with Simile. 4: Population submodels

Muetzelfeldt

2000-03-08T15:17:51

Robert Muetzelfeldt