Biodiversity in silvopastoral systems: A global review and meta-analysis

Understanding the biodiversity values of silvopastoral systems (SPS) is crucial to developing ecologically sustainable grazing systems that can integrate production and conservation goals. Nevertheless, the understanding of how effectively SPS enhance biodiversity compared to other land use systems remains limited. A global systematic review was conducted using 253 publications to identify knowledge gaps in biodiversity research in SPS. Additionally, a meta-analysis was carried out using 730 comparisons from 78 publications to quantify the effect of SPS on biodiversity compared to their references, including open pastures and ungrazed forests. The results highlight the need for further biodiversity research on vertebrates and microbes across SPS types, particularly systems with planted trees or shrubs in underrepresented regions. The meta-analysis showed that the effect of SPS on biodiversity compared to their references varied with system types and taxonomic groups. SPS supported 28.4% higher biodiversity than open pastures. SPS with native (unplanted) and planted trees both increased biodiversity relative to open pastures by 36.3% and 20.9%, respectively. However, SPS with native trees had 18.1% lower biodiversity than native forests. At the taxa level, native tree-based SPS exhibited similar biodiversity of birds, but lower levels of plants and invertebrates relative to native forests. In contrast, these native systems enhanced invertebrate communities compared to open pastures. These findings suggest that transitioning from open grazing systems to SPS represents a promising strategy to enhance biodiversity. Furthermore, establishing SPS with native trees serves as a complementary approach to biodiversity conservation, rather than a direct substitute for native forests.