VARIABLES	RANGE	DEFAULT VALUE	DESCRIPTION
global variables
time-steps	0-200	N/A	Each time step in the model represents 1 year.  The model is run for a total of 200 years for each iteration.
sd-density	N/A	N/A	This is the standard deviation of the resources / population for each settlement.  As the standard deviation increases, migration becomes increasingly likely.
number-of-migrations	N/A	N/A	This variable keeps track of how many total migrations have taken place for each run.
numTurtles	200-400	200	This variable represents the number of agents in the model run.
max-harvest	2.0-4.0	4.0	This is the maximum harvest which an agent can get at any time step before the productive potential of a patch is taken into account.
max-intensity	2.0-4.0	4.0	This is the maximum intenstiy with which an agent can use a particular patch.
time-to-regrow	10-20	10	This is the maximum number of time steps it takes for a patch to regenerate 1 p-resource value.
storage-decay-rate	0.00-1.00	0.10	This is the proportion of an agent's storage which decays at each time step.
wait-to-migrate	20-40	30	This is the maximum time an agent will wait before considering migration.
think-sa-prob	0.00-1.00	0.10	This value is the probability that an agent will choose to migrate to a location based on information relating to the social attractiveness of each settlement.
social-attractl?	on-off	off	This is a switch which, when turned on, allows agents to consider the social attractiveness of each settlement in their decisions to stay or move
imperfect-info?	on-off	off	This is a switch which, when turned on, will introduce error into the information given to an agent regarding each settlement.
uncertainty	0.00-1.00	0.40	This value is the maximum proportion of random variation in the information an agent recieves when imperfect-info? Is on.
settlement variables
p-resource	0-8	N/A	This is the resource level for each patch.  As agents use the resource, this value declines.  It can also regrow, but the initial value for each patch is the maximum value a patch can have.
resources-1…resources-7	N/A	N/A	This is the sum of the p-resources for every patch within a particular settlment.
pop-1...pop-7	N/A	N/A	This is the current population of a settlement.
density-1...density-7	N/A	N/A	This is the resource value / population value for each settlement.
sa...sa-7	N/A		This is the sum of the time-in-settlement value for all agents currently in a settlement.  Thus, this value is related both to the total population and the amount of time each agent has spent in this settlement.
agent variables
storage	N/A	N/A	This is the amount of stored resources an agent currently has.
resource-requirement	1.4-1.6	N/A	This is the amount of resources an agent consumes at each time step.  This is based on the household-size variable.
household-size	1-3	N/A	This value is randomly assigned to each agent upon setting up the model which determines the resource requirement..
time-in-settlement	N/A	N/A	This is the amount of time an agent has spent in its current settlement.
Table 1.  Description of primary variables used in the PALM model.