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This function applies a minimum size constraint on a scenario() created object. The rationale here is that for a given species isolated habitat patches smaller than a given size might not be viable / unrealistic for a species to establish a (long-term) presence.

The idea thus is to apply a constraint in that only patches bigger than a certain size are retained between timesteps. It has thus the potential to reduce subsequent colonizations of neighbouring patches.

Usage

add_constraint_minsize(
  mod,
  value,
  unit = "km2",
  establishment_step = FALSE,
  ...
)

# S4 method for BiodiversityScenario,numeric
add_constraint_minsize(
  mod,
  value,
  unit = "km2",
  establishment_step = FALSE,
  ...
)

Arguments

mod

A BiodiversityScenario object with specified predictors.

value

A numeric value describing the minimum amount of area of a given patch

unit

A character of the unit of area. Options available are km2 (Default), ha and pixel.

establishment_step

A logical flag indicating whether a given patch is only to be removed if wasn't small in a previous time step (not yet implemented!)

...

passed on parameters. See also the specific methods for adding constraints.

Details

Area values in a specific unit need to be supplied.

Note

This function requires that a scenario has a set threshold()!

Examples

if (FALSE) {
scenario(fit) |>
 add_predictors(future_covariates) |>
 threshold() |>
 add_constraint_minsize(value = 1000, unit = "km2") |>
 project()
}