Cross-taxon congruence between predatory arthropods and plants across Mediterranean agricultural landscapes

Although arthropods are among the most diverse, abundant and ecologically important animals in terrestrial ecosystems, they generally neglected biodiversity inventories due to their complex systematics overwhelming diversity, coupled with current decline number of taxonomists. For this reason, several surrogate groups for arthropod diversity have been proposed, plants being identified as a good putative cross-taxon indicator. By sampling three ground-dwelling (rove beetles, ground beetles spiders) 300 sites across 15 landscapes including multiple semi-natural agricultural habitats, we tested habitat-dependence scale-dependence congruence. Plant species richness was poor predictor predatory arthropods. Among predator groups, appeared best potential other predators. This is backed by fact that were extremely diverse all habitats usually easier identify than both rove spiders. Decreasing scale at which congruence improved strength plant not suitable indicator arthropods, vegetation structure played significant role influencing natural habitats. Our results highlight need explore relationships fine habitat resolution scale, strong correlations obtained only taking into account identity.