Opening the canopy to restore spider biodiversity in protected oakwoods

A mosaic of patches in various successional stages is key to maintaining high biodiversity in open temperate woodlands. The abandonment of traditional management, such as once widespread coppicing, has caused biodiversity loss and a shift to ecologically homogeneous communities. Invertebrates are one of the taxonomic groups that suffered the most from the lack of a regular disturbance regime. Despite the obvious importance of active management in maintaining high biodiversity in open temperate woodlands, our knowledge on its contribution to spider conservation is still poor. We investigated how the coppicing restoration affects the diversity of ground-dwelling spiders in the oakwoods of Podyjí National Park in the Czech Republic. We sampled the spider assemblages using pitfall traps within 10 plots in three successional stages: initial, advanced, and late successional stage (control). We collected a total of 9 919 individuals belonging to 143 spider species. The species richness was positively influenced by restoration and reached the highest values in the advanced successional stage. Each successional stage hosted distinct spider assemblages. The trait diversity (RaoQ) was very low in the late successional stage, primarily accommodating small spider species with a preference for shaded and humid habitats. On the other hand, canopy thinning supported high trait diversity of light-demanding and threatened species. Our results showed that the restoration of traditional coppicing could be an appropriate tool for maintaining biodiversity of ground-dwelling spiders in open oakwoods.