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Compute Game Browsing Pressure Index by Department

Source: R/data-hunting.R
compute_game_pressure_index.Rd

Calculates a browsing pressure index (0-100) for each department based on hunting harvest statistics. Higher values indicate higher game populations and thus higher browsing pressure on forests.

Usage

compute_game_pressure_index(
  hunting_data = NULL,
  season = "latest",
  weights = c(chevreuil = 0.3, cerf = 0.25, sanglier = 0.15, chamois = 0.08, mouflon =
    0.07, daim = 0.06, isard = 0.05, cerf_sika = 0.04),
  normalize_by = "rank",
  dept_forest_area = NULL
)

Arguments

hunting_data

Data.frame from download_hunting_data, or NULL to download automatically.

season

Character. Hunting season to use (e.g., "2022-2023"). Default "latest" uses most recent available.

weights

Named numeric vector. Weights for species contribution to browsing pressure. Default weights reflect relative forest impact: chevreuil (0.30), cerf (0.25), sanglier (0.15), chamois (0.08), mouflon (0.07), daim (0.06), isard (0.05), cerf_sika (0.04).

normalize_by

Character. How to normalize harvest numbers: "area" (per km2 of forest, requires dept_forest_area), "rank" (percentile rank), or "minmax" (min-max scaling). Default "rank".

dept_forest_area

Named numeric vector. Forest area (km2) by department code. Only needed if normalize_by = "area". If NULL, uses built-in estimates.

Value

A data.frame with columns:

  • code_dept: Department code

  • nom_dept: Department name

  • pressure_index: Browsing pressure index (0-100)

  • <species>_harvest: Harvest count for each species present

Details

The pressure index combines harvest statistics for 8 large game species affecting forest regeneration:

  • Chevreuil (roe deer): Main browser, high impact on regeneration

  • Cerf (red deer): Significant browser, bark stripping

  • Sanglier (wild boar): Root damage, seed predation

  • Chamois: Alpine browser, localized impact

  • Isard (Pyrenean chamois): Pyrenees only

  • Mouflon: Mediterranean zones

  • Daim (fallow deer): Browser, localized populations

  • Cerf sika (sika deer): Bark stripping, limited range

Weights reflect relative impact on forest browsing (not total damage). Mountain ungulates (chamois, isard, mouflon) have lower weights as they primarily affect alpine/subalpine forests.

See also

Other data-acquisition: download_hunting_data(), get_game_pressure_raster()

Examples

if (FALSE) { # \dontrun{
# Compute pressure index for latest season
pressure <- compute_game_pressure_index()

# Get departments with highest pressure
high_pressure <- pressure[pressure$pressure_index > 75, ]

# Use with R4 indicator
# (Convert to spatial and join with parcels)
} # }