Calculate Ecological Connectivity (B3)

Computes ecological connectivity using a multi-method approach combining structural metrics, cost distance, graph theory, and kernel dispersal, as described in tutorial 04. Uses BD Foret data and DEM when available.

Usage

indicator_biodiversity_connectivity(
  units,
  bdforet = NULL,
  dem = NULL,
  max_distance = 5000
)

Arguments

units

An sf object with forest parcels.

bdforet

An sf object with BD Foret V2 polygons. If NULL, returns fallback score of 50 for all parcels. Default NULL.

dem

A SpatRaster with digital elevation model. Used for cost distance refinement. Default NULL.

max_distance

Numeric. Maximum distance threshold (meters) for local connectivity scoring. Default 5000.

Value

The input sf object with added column B3 (0-100 score, higher = better).

Details

Four components are combined (25

1. **Structural** (landscapemetrics): cohesion, nearest-neighbour distance, aggregation index of forest patches.

2. **Cost distance** (terra): resistance-weighted distance from parcels to nearest forest patch.

3. **Graph** (igraph): proportion of forest patches in the largest connected component (threshold 500m).

4. **Kernel dispersal** (adehabitatHR): kernel density estimation of forest parcel centroids, ratio of 95 as proxy for functional connectivity.

Final score: B3 = 0.7 * B3_global + 0.3 * local_connectivity where local_connectivity is distance-based (sf) per-parcel adjustment.

See also

Other biodiversity-indicators: indicator_biodiversity_protection(), indicator_biodiversity_structure()