Data from: Tree diversity enhances predation by birds but not by arthropods across climate gradients

Tree diversity can promote both predator abundance and diversity. However,
whether this translates into increased predation and top-down control of
herbivores across predator taxonomic groups and contrasting environmental
conditions remains unresolved. We used a global network of tree diversity
experiments (www.treedivnet.ugent.be; TreeDivNet) spread across three
continents and three biomes to test the effects of tree species richness
on predation across varying climatic conditions of temperature and
precipitation. We recorded bird and arthropod predation attempts on
plasticine caterpillars in monocultures and tree species mixtures. Both
tree species richness and temperature increased predation by birds, but
not by arthropods. Furthermore, the effects of tree species richness on
predation were consistent across the studied climatic gradient. Our
findings provide evidence that tree diversity strengthens top-down control
of insect herbivores by birds, underscoring the need of implementing
conservation strategies that safeguard tree diversity to sustain ecosystem
services provided by natural enemies in forests.