# nicheOverlap

##### Niche overlap

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

##### 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

```
# NOT RUN {
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)
# }
```

*Documentation reproduced from package dismo, version 1.3-3, License: GPL (>= 3)*