Buffer habitat raster

Buffer around the habitat a given distance in metres using terra::focalMat(d = buffer_radius, type = "circle"). This operation is used to identify connected patches of habitat. Two patches will connect when their edge-to-edge gap is <= 2 * buffer radius. So, we recommend you specify the buffer_radius value to be half the interpatch distance, which is the distance past which habitat patches are no longer considered connected. For example, if your interpatch distance is 500m, set buffer_radius = 250.

Usage

habitat_buffer(habitat, buffer_radius)

Arguments

habitat

Terra SpatRaster. Habitat raster.

buffer_radius

Numeric. The radius in metres around the habitat. Since patches of habitat will be connected when their edge-to-edge gap is <= 2 * buffer radius, we recommend you specify buffer_radius to be half the "interpatch distance". This is the distance past which habitat patches are no longer considered connected. For example, if your interpatch distance is 500m, set buffer_radius = 250. The buffer can only be represented if it is at least one raster cell, i.e. keep resolution <= interpatch_distance / 2. Below that the buffer is a no-op: habitat_buffer() warns and returns the habitat unchanged. See vignette("interpatch-distance-and-resolution").

Value

Terra SpatRaster with buffered habitat.

See also

vignette("interpatch-distance-and-resolution") for the relationship between interpatch distance, buffer radius, and resolution.

Examples

lizard_habitat <- example_habitat()
library(terra)
plot(lizard_habitat, col = "darkgreen", legend = FALSE)

# run with a small buffer radius
lizard_buff <- habitat_buffer(lizard_habitat, buffer_radius = 10)
plot(lizard_buff, col = "lightgreen", legend = FALSE)
plot(lizard_habitat, col = "darkgreen", legend = FALSE, add = TRUE)