adehabitat (version 1.1-1)

mcp: Estimation of the Home Range Using the Minimum Convex Polygon Estimator

Description

mcp computes the home range of several animals using the minimum convex polygon estimator. mcp.area is used for home-range size estimation. This function requires the package gpclib. plot.hrsize is used to display the home-range size estimated at various levels.

Usage

mcp(xy, id, percent = 95)
mcp.area(xy, id, percent = seq(20,95, by=5)
         unin = c("m", "km"),
         unout = c("ha", "km2", "m2"))
plot.hrsize(x, ...)

Arguments

xy

a data frame containing the coordinates of the relocation of the monitored animals

id

a factor giving the identity of the animal for each relocation

percent

100 minus the proportion of outliers to be excluded from the computation

unin

the units of the relocations coordinates. Either "m" (default) for meters or "km" for kilometers

unout

the units of the output areas. Either "m2" for square meters, "km2" for square kilometers or "ha" for hectares (default)

x

an objet of class hrsize returned by the function mcp.area, or kernel.area (see the help page of this function)

...

additionnal arguments to be passed to the function plot

Value

• mcp returns an object of class area, with one polygon per level of the factor ID. mcp.area returns a data frame of class hrsize, with one column per animal and one row per level of estimation of the home range

Details

This function computes the Minimum Convex Polygon estimation after the removal of (100 minus percent) percent of the relocations the farthest away from the barycenter of the home range (computed by the arithmetic mean of the coordinates of the relocations for each animal).

References

Mohr, C.O. (1947) Table of equivalent populations of north american small mammals. The American Midland Naturalist, 37, 223-249.

See Also

chull, area.plot to have a graphical display of the home ranges, as.area for additionnal information on the class area, and area2dxf for further exportation toward a GIS. s.chull for another way to display MCP

Examples

data(puechabon)
locs <-  puechabon$locs

cp <- mcp(locs[,4:5], locs[,1])

## Plot the home ranges
opar <- par(mar = c(0,0,0,0))
area.plot(cp)

## ... And the relocations
points(locs[,4:5], pch = 16, col = as.numeric(locs[,1]))
par(opar)

## Computation of the home-range size:
if (require(gpclib)) {
  (cuicui1 <- mcp.area(locs[,4:5], locs[,1]))
  plot(cuicui1)
}