sperich (version 1.5-8)

species.range: Species range estimation

Description

This function estimates the species range based on given occurrences of one species.

Usage

species.range(dataset.one.species, distance, dimension, shift, 
	resolution=1, landwatermask, upperbound, cross.validation=FALSE)

Value

This function returns a grid which contains the species range information.

Arguments

dataset.one.species

A dataset containing one species with its ID (named: speciesID) and the longitude (named: long) and latitude (named: lat) of the occurrence locations of that species.

landwatermask

A grid containing the land-water-information of the observed area. If a grid cell containes no land, the value of the cell in the landwatermask is -1, otherwise it is 0. Additional, height-informations could be added for land surfaces. In this case, take care of the 'upperbound' value.

distance

The maximum distance in which two occurrences are considered as related occurrences. These two occurrences will be connected with an edge.

dimension

The dimension of the processed grid.

shift

The geographic coordinates of the origin of the grid.

resolution

The resolution of the grid in (geographical) degree.

upperbound

This value determines the height (based on values in 'landwatermask') which is considered to be a barrier for species distribution.

cross.validation

A logical value determining wether a cross-validation is performed.

Author

Maximilian Lange, Sven Lautenbach

Details

This routine estimates the species range based on given occurrences of one species through a geometric interpolation model (details in Raedig et al. 2010).

References

Raedig, C., Dorman, C.F., Hildebrandt, A. and Lautenbach, S. (2010). Reassessing Neotropical angiosperm distribution patterns based on monographic data: a geometric interpolation approach. Biodivers Conserv, 19, 1523-1546.

Examples

##load data
data(dataset.all.species)
data(dataset.landwater)

##create grid parameters
dimension <- getDimension(dataset.all.species, resolution=1)
shift <- getShift(dataset.all.species)

##create landwatermask
landwatermask.nocoast <- createLandwatermask(dataset.landwater, 
					dimension, shift, resolution=1)

##extract datasets of one species out of database
dataset.one.species <- extract.species(dataset.all.species, 3)

##estimate species range
species.range.tmp <- species.range(dataset.one.species, distance=5, 
		dimension, shift, resolution=1, landwatermask.nocoast)