dismo: nicheOverlap – R documentation

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nicheOverlap

Niche overlap

Description

Compute niche overlap from predictions of species distributions with the 'I' or 'D' similarity statistic of Warren et al. (2009). The statistic ranges from 0 (no overlap) to 1 (the distributions are identical).

Usage

nicheOverlap(x, y, stat='I', mask=TRUE, checkNegatives=TRUE)

Arguments

`x`	RasterLayer with non-negative values (predictions of the probability that a site is suitable for a species)
`y`	RasterLayer with non-negative values, as above
`stat`	character either 'I' or 'D' to get the statistic with that name
`mask`	logical. If `TRUE` the function removes cells from `x` that are `NA` in `y` and vice-versa. If you are sure that such cases do not occur you can set this to `FALSE` to speed up computations
`checkNegatives`	logical. If `TRUE` the function checks of any of the values in `x` and `y` are negative. If you are sure that such cases do not occur you can set this to `FALSE` to speed up computations

Value

numeric

Author(s)

Based on SDMTools::Istat by Jeremy VanDerWal

References

Warren, D.L., R.E. Glor, M. Turelli, and D. Funk. 2009. Environmental niche equivalency versus conservatism: quantitative approaches to niche evolution. Evolution 62:2868-2883; Erratum: Evolution 65: 1215

Examples

r1 <- raster(nr=18, nc=36)
r2 <- raster(nr=18, nc=36)
set.seed(0)
r1[] <- runif(ncell(r1))
r2[] <- runif(ncell(r1))
nicheOverlap(r1, r2)

dismo

Species Distribution Modeling

v1.3-3

GPL (>= 3)

Authors

Robert J. Hijmans, Steven Phillips, John Leathwick and Jane Elith

Initial release

2020-11-16