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Variation in Taxonomic Distinctness (Lambda+)

Source: R/classical_indices.R
vartd.Rd

Calculates the variation in taxonomic distinctness (VarTD, Lambda+) based on Clarke & Warwick (2001).

Usage

vartd(species, tax_tree, weights = NULL)

Arguments

species

Character vector of species names present in the community.

tax_tree

A data frame representing the taxonomic hierarchy.

weights

Optional numeric vector of weights for taxonomic levels.

Value

A numeric value representing the variation in taxonomic distinctness (Lambda+).

References

Clarke, K.R. & Warwick, R.M. (2001). A further biodiversity index applicable to species lists: variation in taxonomic distinctness. Marine Ecology Progress Series, 216, 265-278.

Examples

tax <- data.frame(
  Species = c("Quercus_robur", "Pinus_nigra", "Fagus_orientalis",
              "Abies_nordmanniana"),
  Genus = c("Quercus", "Pinus", "Fagus", "Abies"),
  Family = c("Fagaceae", "Pinaceae", "Fagaceae", "Pinaceae"),
  Order = c("Fagales", "Pinales", "Fagales", "Pinales"),
  stringsAsFactors = FALSE
)

spp <- c("Quercus_robur", "Pinus_nigra", "Fagus_orientalis")
vartd(spp, tax)
#> [1] 0.2222222