Structural connectivity of terrestrial level 3 EUNIS habitats

An analysis workflow quantifies the connectivity of terrestrial habitat types by combining continuous habitat-probability surfaces with fragmentation pressures-road infrastructure—and masking land-cover mismatches. A consistent Europe-wide set of maps quantifies structural connectivity for EUNIS Level-3 habitats, derived from 100 m habitat-probability surfaces (0–1) produced by NaturaConnect (Si-Moussi et al., 2024; Horizon EU, Task 6.3, Deliverable 6.2).Connectivity is measured using probability-weighted, normalized Effective Mesh Size (Meff_pw_norm; Jaeger, 2000) in a moving-window approach. Pixels with low probability (P < 0.1) are excluded; land-cover mismatches are masked using a CLC–EUNIS crosswalk (Si-Moussi et al., 2024) with CORINE Land Cover 2018 (EEA, 2021); and road corridors are removed using a binary OpenStreetMap roads raster. Meff is computed on probability-weighted connected components within a 10.1 × 10.1 km window and divided by the window area (102.01 km²), yielding a 0–1 fraction of effectively connected habitat per pixel.The resulting dataset offers a practical, comparable basis to describe the state of ecological connectivity for habitats of interest, including those protected under the Natura 2000 network.