Abstract
Habitat restoration -- the deliberate intervention to assist recovery of a degraded or destroyed ecosystem toward a
reference condition -- has emerged as a central strategy for biodiversity conservation and is now mandated at scale
through the EU Nature Restoration Law (2024/1991) and the Kunming-Montreal Global Biodiversity Framework 30x30
and restoration targets. This review synthesises evidence from 284 peer-reviewed studies published between 2000 and
2024 on faunal recovery following habitat restoration across European terrestrial and freshwater ecosystems, covering
six restoration types (riparian, peatland, heathland, grassland, woodland, and river floodplain) and five vertebrate and
invertebrate groups. Meta-analysis of 148 studies providing quantitative recovery data confirms that restoration increases
faunal diversity by a mean of 34.8% (95% CI: 28.4-41.2%) relative to degraded controls, but recovery to reference
condition levels takes 8-42 years depending on taxon and restoration type. Recovery rates are highest for mobile
generalists (breeding birds, butterflies; mean 85.4% of reference richness at 10 years) and slowest for sedentary
specialists (freshwater molluscs, amphibians; mean 42.4% at 10 years). The single most important predictor of
restoration success across all studies was donor-population connectivity -- access to source populations for
recolonisation -- which accounted for 38.4% of variance in recovery rate (partial R2 in meta-regression). Management
intensity post-restoration (active vegetation management, predator control, water level management) was the second
most important predictor (partial R2 = 0.24). These findings provide an evidence synthesis for prioritising restoration
investment and design under EU Nature Restoration Law national planning obligations.