Simulate range expansion simulation

This function produces dispersal scenarios, considering different habitat networks properties, evaluating the variation in dispersal speed and dispersal maximum distance (of range expansion).

Usage

manage_expansion_sim(mapsize, dist_m, areaM, areaSD, Npatch,percI, 
                    param, b=1, tsteps, iter, variable,var_min,var_max,by)

Arguments

mapsize

Landscape mosaic side length, in meters. To be internally passed to rland.graph

dist_m

Minimum distance between patches (centroid).To be internally passed to rland.graph

areaM

Mean area (in hectares). To be internally passed to rland.graph

areaSD

SD of the area of patches, in order to give variability to the patches area. To be internally passed to rland.graph

Npatch

Number of patches. To be internally passed to rland.graph

percI

Percentage of patch occupancy in the starting landscape. To be internally passed to range_expansion

param

Parameter data frame delivered by parameter.estimate. To be internally passed to range_expansion It includes:

alpha - Parameter relating extinction with distance.
y - Parameter y in the colonization probability.
e - Parameter defining the extinction probability in a patch of unit area.
x - Parameter scaling extinction risk with patch area.

b

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

tsteps

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

iter

Number of iterations of the simulation procedure.

variable

Landscape graph characteristic to be varied. One of the following:

area - Mean patch area (in hectares).
dist - Minimum distance between patches (centroid).
npatch - Number of patches.
sizevar - SD of the area of patches.

var_min

Minimum value the changing variable can assume (beware of units used in each case).

var_max

Maximum value the changing variable can assume (beware of units used in each case).

by

Rate of variation of the changing variable.

Details

For details regarding the arguments that are to be internally passed to other functions, see the respective functions. Any of the arguments dist_m, areaM, areaSD, Npatch would be unnecessary if the respective variable is the one to be evaluated (it depends on the parameter variable).

Value

Returns a list of eight data frames. For the first four data frames (NORTH, SOUTH, EAST and WEST) each data frame's first column is the name of the variable to be changed. The other two columns are:

MEAN EXPANSION SPEED: Expansion speed in each simulated scenario. Speed given in km/time step
MAXIMUM EXPANSION DISTANCE: Maximum distance of the expanded range, from an occupied site. Given in km.

The other four data frames have detailed information on the simulations for each of the values of parameter "variable". The first column has the distance (in km), and each of the following columns has the time step at which each distance was colonized for each of the simulations.

Warning

This function might be time consuming, and the code is experimental and should be improved in future versions of MetaLandSim.

Author

Frederico Mestre and Fernando Canovas

Examples


if (FALSE) { # \dontrun{

data(param1)


sim_range <- manage_expansion_sim(mapsize=1000, dist_m=0, areaM, areaSD=0.001, 
                                  patch=300,percI=50, param=param1, b=1, 
                                  tsteps=100, iter=100,variable="area",var_min=0.01,
                                  var_max=0.6,by=0.1)
} # }