Global and regional effects of forest certification on faunal biodiversity: a systematic review and case study from Portugal

Worldwide forest ecosystems are crucial for biodiversity conservation and providers of several ecosystem services, but face increasing threats from anthropogenic activities, exploitation, deforestation, invasive species, habitat fragmentation and climate change. To reduce the negative impacts, forest certification was developed as an instrument to encourage the sustainable management of forests. In this study, we tested the hypothesis that certification can have a positive influence on fauna conservation by improving habitat quality. We reviewed existing literature on a global scale, and we also analyzed a case study of certified forests, or forests in process of certification, in Portugal, including vegetation surveys and species presence data for amphibians, reptiles, birds and mammals. Data analysis involved Spearman correlations and Generalised Linear Mixed Models (GLMM) to explore associations between fauna richness and habitat features. Our results reveal that while certification appears to benefit fauna, by enhancing habitat conservation and supporting diverse fauna resources, the available research is predominantly European, with invertebrates, reptiles, amphibians, and fish receiving less attention compared to birds and mammals. We identified positive correlations between fauna richness and environmental characteristics, including regional differences. These findings indicate that certified forests can support higher faunal diversity when management maintains heterogeneous vegetation and water features, though effects vary among taxa and regions. Despite the role that forest certification can have in reducing some negative impacts of forestry on wildlife, further research, monitoring and long-term analysis are essential.