raster.evenness {BAT}R Documentation

Maps of phylogenetic/functional evenness of species or individuals.

Description

Regularity of distance and abundance between any two species in a community using rasters of species distributions (presence/absence or abundance).

Usage

raster.evenness(
  layers,
  tree,
  distance,
  method = "expected",
  func = "camargo",
  abund = TRUE
)

Arguments

layers

A Raster* object of species distributions (typically a multi-layer type: RasterStack or RasterBrick).

tree

A phylo or hclust object (used only for PD or FD) or alternatively a species x traits matrix or data.frame to build a functional tree.

distance

A dist object representing the phylogenetic or functional distance between species.

method

Calculate dispersion using "expected" values (default) or values based on "contribution" of species to the tree.

func

Calculate dispersion using "Camargo" (default) or "Bulla" index.

abund

A boolean (T/F) indicating whether evenness should be calculated using abundance data.

Details

Evenness is calculated based on the index of Bulla (1994) using the values of both edge lengths in the tree and their abundance.

If no tree or distance is provided the result is the original index of Bulla with correction.

Value

A raster object representing evenness in space.

References

Bulla, L. (1994) An index of evenness and its associated diversity measure. Oikos, 70: 167-171.

Examples

sp1 <- raster::raster(matrix(c(NA,1,1,1,1,0,0,0,0), nrow = 3, ncol = 3, byrow = TRUE))
sp2 <- raster::raster(matrix(c(0,0,0,0,1,1,1,1,1), nrow = 3, ncol = 3, byrow = TRUE))
sp3 <- raster::raster(matrix(c(0,0,0,1,1,1,0,0,0), nrow = 3, ncol = 3, byrow = TRUE))
spp <- raster::stack(sp1, sp2, sp3)
tree <- hclust(dist(c(1:3), method="euclidean"), method="average")
raster.evenness(spp, tree)

[Package BAT version 2.6.0 Index]