Kai L. Kopecky, Max C. N. Castorani, Ty Tuff, Audrey Barker Plotkin, David M. Bell, Jill F. Johnstone, John S. Kominoski, Jesse B. Nippert, Christopher J. Nytch, Steven C. Pennings, Daniel C. Reed, Aaron B. Shiels, Katharine N. Suding
Ecosystems carry memory through the material remains of organisms. Foundation species-trees, grasses, corals, and oysters-while alive are central to ecosystem structure, and the remains of these organisms continue to influence ecological processes after death. We conducted, to our knowldge, the first continental-scale exploration of how dead foundation species influence living conspecifics, leveraging long-term experiments and observations (2 to 32 years) from 10 ecosystems (five terrestrial and five marine) across the US Long Term Ecological Research Network. We found that material legacies commonly alter demographic processes, ranging from a 50% reduction to a 12-fold increase. The ubiquity of these postmortem effects reveals an underappreciated dimension of ecological memory that shapes pathways of ecosystem resilience, reorganization, and collapse, providing a critical management tool in an era of increasing disturbance- and climate-driven mortality events.