The potential of agroforestry and small fields to enhance ground-dwelling spiders

Abstract Agroforestry systems integrate open and woody elements within agricultural landscapes, creating structurally complex ecosystems that provide habitats for diverse taxa, including spiders. This study examined the effect of agroforestry systems on ground-dwelling spiders across multiple European countries. In each country, several mature agroforestry plots were compared with non-agroforestry agricultural and woody reference plots. Our findings reveal that agroforestry supports species from both open and forested habitats, contributing to landscape-scale biodiversity. Alpha diversity was higher in silvopastures than in forests, but beta diversity (turnover) was not significantly different between agroforestry and other habitat types. Instead, there was a trend towards decreasing spider richness with increasing field size, across all habitat types. High variability in spider diversity across regions suggests that local environmental factors, such as tree species, management practices, and climate, play a key role in shaping spider communities. Our study supports that mosaic of small fields with diverse land uses, combined with seminatural habitats and structurally heterogeneous productive systems like agroforestry, can enhance biodiversity and species-rich agricultural landscapes.