schoenr: Calculate Schoener's D metric of niche overlap
In GwenAntell/kerneval: Kernel density estimation with selection-biased data

schoenr

R Documentation

Calculate Schoener's D metric of niche overlap

Description

Schoener's D metric quantifies niche overlap between two discretised probability functions. The schoenr function modifies the metric for continuous probability distributions.

Usage

schoenr(d1, d2, a = NULL, b = NULL)

Arguments

`d1`	A density distribution.
`d2`	A density distribution.
`a`	The lower and upper limits of comparison. Each density will be rescaled such that the integral over the interval `[a,b]` sums to unity. If empty, the minimum and maximum of the intersection of `d1$x` and `d2$x` will be used.
`b`	The lower and upper limits of comparison. Each density will be rescaled such that the integral over the interval `[a,b]` sums to unity. If empty, the minimum and maximum of the intersection of `d1$x` and `d2$x` will be used.

Details

D was originally defned as the sum of the absolute difference in resource use frequencies for every category i. The sum is rescaled by 0.5 to give the per-niche value, and then subtracted from 1 so as to be a similarity metric (i.e. D = 1 indicates identical niches). schoenr replaces the sum with an integral on the absolute difference between two estimated kernel density functions.