Changes in food web structure between high- and low-productivity environments are driven by shifts in the diets of intermediate predators, not top predators. By studying the diets of different predator groups using DNA and stable isotopes, researchers found that in high-productivity habitats, intermediate predators switched to a more predatory prey base, while top predators showed increases in their trophic position but no changes in their diet composition. This study shows how different predators respond to changes in ecosystem productivity, providing insights into how predator-prey interactions are influenced by environmental factors.