This function computes overlap metrics between two rasters. It currently
implements Schoener's D and the inverse I of Hellinger's distance.
Usage
niche_overlap(x, y, method = c("Schoener", "Hellinger"))
Arguments
- x
a terra::SpatRaster with a single layer
- y
a terra::SpatRaster with a single layer
- method
a string (or vector of strings) taking values "Schoener" and
"Hellinger"
Value
a list of overlap metrics, with slots D and I (depending on
method)
Details
Note that Hellinger's distance is normalised by dividing by square root of 2
(which is the correct asymptote for Hellinger's D), rather than the incorrect
2 used originally in Warren et al (2008), based on the Erratum for that
paper.
References
Warren, D.L., Glor, R.E. & Turelli M. (2008) Environmental niche
equivalency versus conservativism: quantitative approaches to niche
evolution. Evolution 62: 2868-2883
