Abstract

The ongoing biodiversity crisis has urged the scientific community to concentrate more research efforts on the mechanisms underlying the mass extinctions that have repeatedly affected our planet in deep time. This work implements a novel combination of palaeoecological and statistical routines to assess disruptions in the trophic architecture of non-avian dinosaur communities across the latest Cretaceous (83.6–66.0 Mya) of North America. Using these extinct beasts as model organisms, this work aims at increasing our ability to predict the susceptibility of ecological communities to extinction events under different levels of environmental disturbance. There was a trophic shift in the large, bulk-feeding herbivorous ornithischians and theropod carnivores during the Campanian–Maastrichtian transition that led to a simplification of North American terrestrial food webs several million years before the asteroid impact. Their disappearance during the Maastrichtian (72.0–66.0 Mya) made terrestrial communities more prone to extinction in the aftermath of the Chicxulub impact, which suggests that conservation schemes should pay special attention to keystone species in present-day food webs. In conclusion, palaeoecological transitions in the fossil record provide a valuable source of information for predicting the potential consequences of large-scale disturbances on contemporary biodiversity.