Restoration effects on avian populations and communities: an integrative review

Abstract

Abstract Ecological restoration is increasingly used to recover biodiversity in degraded ecosystems, yet its effectiveness for avifauna varies across contexts. We conducted an integrative review of studies assessing the effects of restoration on bird populations and communities worldwide. Search in Scopus, Web of Science, and Google Scholar yielded 192 studies, covering forests, savannahs/grasslands, and wetlands across 37 countries. Most studies implemented active restoration, with fewer using passive or mixed approaches. Overall, restoration effects on birds were predominantly positive (81.3%) with neutral outcomes reported in 16.1% of studies and negative outcomes in 2.6%. Positive responses included increases in species richness, abundance, and community resemblance to reference habitats; however, parity with native systems often depended on long-term maintenance and successional development. Time from intervention strongly modulated outcomes, with older plantings consistently supporting higher richness and abundance. Projects relying on native vegetation tended to outperform those dominated by exotic species. Beyond taxonomic metrics, most studies assessing functional and phylogenetic diversity reported convergence toward native reference communities, though some documented losses of evolutionary history and specialization. Geographically, publications were concentrated in the United States and Australia, underscoring gaps in tropical and Global South biomes. Collectively, the evidence indicates that restoration can meaningfully advance avian conservation when actions prioritize native species, structural heterogeneity, and landscape connectivity, and when monitoring spans sufficient temporal scales to capture community assembly and demographic viability. These findings provide actionable guidance for restoration design and evaluation, and highlight priorities for future research on long-term dynamics, edge effects, predation, and specialist taxa.