MetaLandSim (version 0.2)

range_expansion: Produce a range expansion model

Description

This function returns the expansion probability, from a landscape with a given set of parameters, into the four cardinal directions. This can subsequently be converted in a dispersal model by the function range_raster. The dispersal model can be combined with an ecological niche model.

Usage

range_expansion(rl, percI, amin, param, b, tsteps, iter)

Arguments

rl

Object of class 'landscape'. Starting landscape for the expansion procedure.

percI

Pecentage of patch occupancy in the starting landscape.

amin

Minimum area for species persistence.

param

Parameter data frame delivered by parameter.estimate, including:

• alpha - Parameter relating extinction with distance.
• y - Parameter y in the colonization probability.
• e -

b

Parameter scaling emigration with patch area (if conn='op1' or 'op2') in spom. By default, equal to 1.

tsteps

Number of time steps to simulate (e.g. years).

iter

Number of iterations of the simulation procedure.

Value

• This function returns a list, of class 'expansion', of four data frames with the proportion of occupations at several distances from the closest occupied landscape mosaic. These four data frames correspond to the proportion of occupation to the north, south, east and west. Each data frame has the following columns:
  • DISTANCE - Distance (mapsize x number of landscapes).
  • OCCUPATION - How many times did the landscape at this distance got occupied by the species (from a total of 'iter' repetitions).
  • PROPORTION - Proportion of occupation for the landscape at this distance (OCCUPATION/iter).

See Also

range_raster

Examples

#Produce a model of range expansion:
#Note: this function should be run with >100 iterations (parameter 'iter').

data(rland)
data(param1)

rg_exp1 <- range_expansion(rl=rland, percI=50, amin=0, param=param1, b=1, tsteps=100, iter=100)