| breeding.density {spatialEco} | R Documentation |
Breeding density areas (aka, core habitat areas)
Description
Calculates breeding density areas base on population counts and spatial point density.
Usage
breeding.density(x, pop, p = 0.75, bw = 6400, b = 8500, self = TRUE)
Arguments
x |
sf POINT object |
pop |
Population count/density column in x |
p |
Target percent of population |
bw |
Bandwidth distance for the kernel estimate (default 8500) |
b |
Buffer distance (default 8500) |
self |
(TRUE/FALSE) Should source observations be included in density (default TRUE) |
Details
The breeding density areas model identifies the Nth-percent population exhibiting the highest spatial density and counts/frequency. It then buffers these points by a specified distance to produce breeding area polygons. If you would like to recreate the results in Doherty et al., (2010), then define bw = 6400m and b[if p < 0.75 b = 6400m, | p >= 0.75 b = 8500m]
Value
A list object with:
pop.pts sf POINT object with points identified within the specified p
pop.area sf POLYGON object of buffered points specified by parameter b
bandwidth Specified distance bandwidth used in identifying neighbor counts
buffer Specified buffer distance used in buffering points for pop.area
p Specified population percent
Author(s)
Jeffrey S. Evans <jeffrey_evans@tnc.org>
References
Doherty, K.E., J.D. Tack, J.S. Evans, D.E. Naugle (2010) Mapping breeding densities of greater sage-grouse: A tool for range-wide conservation planning. Bureau of Land Management. Number L10PG00911
Examples
library(sf)
n=1500
bb <- rbind(c(-1281299,-761876.5),c(1915337,2566433.5))
bb.mat <- round(cbind(c(bb[1,1], bb[1,2], bb[1,2], bb[1,1]),
c(bb[2,1], bb[2,1], bb[2,2], bb[2,2])),2)
bbp <- st_sfc(st_polygon(list(rbind(bb.mat, bb.mat[1,]))))
pop <- st_as_sf(st_sample(bbp, n, type = "random"))
st_geometry(pop) <- "geometry"
pop$ID <- 1:nrow(pop)
pop$counts <- round(runif(nrow(pop), 1,250),0)
bd75 <- breeding.density(pop, pop='counts', p=0.75, b=8500, bw=6400)
plot(st_geometry(bd75$pop.area), border = NA,
main='75% breeding density areas', col="grey")
plot(st_geometry(pop), pch=20, col='black', add=TRUE)
plot(st_geometry(bd75$pop.pts), pch=20, col='red', add=TRUE)
legend("bottomright", legend=c("selected areas","selected sites", "all sites"),
bg="white", fill=c("grey","red", "black"), pt.cex = 2)