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Create Area of Occupancy (AOO) grid for an ecosystem or species distribution

Source: R/AOO_functions.R
makeAOOGrid.Rd

makeAOOGrid is a generic function that creates grids representing the area of occupancy for distributions based on the input spatial data. It includes capability for specifying whether the least occupied cells collectively containing less than 1% of the ecosystem are counted in the AOO. This functionality is important for assessing the IUCN Red List of Ecosystems Criteria B.

Usage

makeAOOGrid(
  input.data,
  grid.size = 10000,
  names_from = NA,
  bottom.1pct.rule = TRUE,
  percent = 1,
  jitter = TRUE,
  n_jitter = 35
)

Arguments

input.data

Spatial object (sf or SpatRaster) of an ecosystem or species distribution. Please use a CRS with units measured in metres.

grid.size

A number specifying the width of the desired grid square (in same units as your coordinate reference system)

names_from

the name of the column containing ecosystem labels

bottom.1pct.rule

Logical. If TRUE, grid cells containing the least ecosystem area are dropped up to 1% of the total distribution.

percent

Numeric. The minimum percent to be applied as a threshold for the bottom.1pct.rule

jitter

logical. Whether grid randomization should be applied to units with low grid counts.

n_jitter

the number of grids to test for ecosystems near the AOO thresholds. Ignored if jitter = FALSE.

Value

A shapefile of grid cells occupied by an ecosystem or species, or a list of these if multiple ecosystems were input.

References

IUCN 2024. Guidelines for the application of IUCN Red List of Ecosystems Categories and Criteria, Version 2.0. Keith, D.A., Ferrer-Paris, J.R., Ghoraba, S.M.M., Henriksen, S., Monyeki, M., Murray, N.J., Nicholson, E., Rowland, J., Skowno, A., Slingsby, J.A., Storeng, A.B., Valderrábano, M. & Zager, I. (Eds.) Gland, Switzerland: IUCN. ix + 94pp. https://doi.org/10.2305/CJDF9122

See also

Other AOO functions: createGrid(), getAOO(), jplot(), top_pct()

Author

Nicholas Murray murr.nick@gmail.com, Calvin Lee calvinkflee@gmail.com, Aniko B. Toth anikobtoth@gmail.com

Examples

m <- matrix(sample(1:4, 500, replace = TRUE, prob = c(4,1,1,6)), nrow=25, ncol=20)
r1 <- terra::rast(m, crs = "EPSG:32755")
AOO_grid <- makeAOOGrid(r1, grid.size = 3)