Mapping the pressure of natural predators on pest arthropods

Natural predators of arthropods provide an important ecosystem service by preying on crop-damaging species. However, measuring the positive impact of natural pest predators is still challenging. We present a framework to estimate the pest-consumption pressure by natural predators across space and project it onto geographical maps. We use DNA metabarcoding and species distribution modelling to integrate predator density estimations with their energetic requirements and direct pest predation, which yields a comprehensive measure of pest-consumption pressure per time-frame and area. We showcase it on a European bat assemblage, and show that bats consume a variety of pests whose predation pressure varies throughout space. We also report that the impact of different predators depends on spatial scale, and that pest predation pressure is negatively correlated with agricultural intensity. Our framework can be used to estimate broad-scale effects of natural predators on pest arthropods as well as to design research and management strategies.