lsm_l_prd function

PRD (landscape level)

Patch richness density (Diversity metric)

lsm_l_prd(landscape, directions = 8)

Arguments

• landscape: A categorical raster object: SpatRaster; Raster* Layer, Stack, Brick; stars or a list of SpatRasters.
• directions: The number of directions in which patches should be connected: 4 (rook's case) or 8 (queen's case).

Returns

tibble

Details

where $m$ is the number of classes and $A$ is the total landscape area in square meters.

PRD is a 'Diversity metric'. It is one of the simplest diversity and composition measures. In contrast to lsm_l_pr, it is a relative measure and following, comparable among landscapes with different total landscape areas.

Because the metric is based on distances or areas please make sure your data is valid using check_landscape.

Units

Number per 100 hectares

Range

PR > 0

Behaviour

Approaches PRD > 1 when only one patch is present and the landscape is rather large. Increases, without limit, as the number of classes increases and the total landscape area decreases.

Examples

landscape <- terra::rast(landscapemetrics::landscape)
lsm_l_prd(landscape)

References

McGarigal K., SA Cushman, and E Ene. 2023. FRAGSTATS v4: Spatial Pattern Analysis Program for Categorical Maps. Computer software program produced by the authors; available at the following web site: https://www.fragstats.org