subpop.radius: Estimate Taxon Dispersal Radius

In gdauby/ConR: Computation of Parameters Used in Preliminary Assessment of Species Conservation Status

Estimate Taxon Dispersal Radius

Description

Calculates the fraction of the maximum distance between species occurrences, which can be used as a proxy of species dispersal ability. This fraction can be used as the radius needed to apply the circular buffer method (Rivers et al 2010) to obtain subpopulations for conservation assessments of extinction risk.

Usage

subpop.radius(
  XY,
  factor.div = 10,
  quant.max = 1,
  mode = "spheroid",
  proj_type = "cea"
)

Arguments

XY	a data.frame. containing the geographical coordinates for each taxon.
factor.div	numeric. denominator value used to obtain the fraction of the maximum distance. Default to 10.
quant.max	numeric. The upper-quantile of the inter-point distance to be considered as a threshold of maximum distance. Can vary between 0 and 1. Default to 1.
mode	character string either 'spheroid' or 'planar'. By default 'spheroid'
proj_type	string or numeric

Details

XY as a data.frame should have the following structure:

It is mandatory to respect field positions, but field names do not matter

1. The first column is contains numeric value i.e. latitude in decimal degrees

2. The second column is contains numeric value i.e. longitude in decimal degrees

3. The third column is contains character value i.e. the names of the species

Value

The estimated radius in kilometres for each taxon.

Author(s)

Renato A. Ferreira de Lima & Gilles Dauby

References

Rivers MC, Bachman SP, Meagher TR, Lughadha EN, Brummitt NA (2010) Subpopulations, locations and fragmentation: applying IUCN red list criteria to herbarium specimen data. Biodiversity and Conservation 19: 2071-2085. doi: 10.1007/s10531-010-9826-9

Examples

mydf <- data.frame(ddlat = c(-44.6,-46.2,-45.4,-42.2,-43.7,-45.0,-28.0),
                   ddlon = c(-42.2,-42.6,-45.3,-42.5,-42.3,-39.0,-17.2),
                   tax = rep("a", 7),
                   stringsAsFactors = FALSE)
                   
subpop.radius(mydf)
subpop.radius(mydf, quant.max = 0.95)
subpop.radius(mydf, factor.div = 15)

gdauby/ConR documentation built on Jan. 30, 2024, 11:10 p.m.