javascript:void(0) Ecological disturbance regimes are shifting and leaving behind novel legacies, like the remnant structures of dead foundation species, which have poorly known impacts on ecosystem resilience. We explored how dead coral skeletons produced by marine heatwaves–material legacies of increasingly common disturbances on coral reefs–influence spatial competition between corals and macroalgae, focusing on whether removing dead branching skeletons stimulates recovery of coral after disturbance. Following a marine heatwave, we removed dead skeletons from reef patches then used underwater photogrammetry and AI-powered image analysis to quantify trajectories of coral and macroalgae. After four years, removal of dead skeletons resulted in 1.6 times more live coral remaining and reduced development of macroalgae by half, relative to patches where skeletons were left intact. Dead skeletons acted as an alternate substrate type that facilitated macroalgae development, and greater macroalgal abundance caused steeper declines in live coral. Lastly, removal of dead skeletons led to five times greater densities of coral recruits on stable (primary) reef substrate. Our findings identify a promising avenue to manage for coral resilience (on reefs where carbonate budgets are not in a deficit) and reveal how material legacies of changing disturbance regimes can alter physical environments to sway the outcomes of spatial competition.

Size-scaling relationships generated across huge variation in body mass from zooplankton to elephants offer critical insight into understanding similarities in species interactions across ecosystems. Yet to what extent ecologists can borrow from these relationships to effectively predict interactions between a single species pair remains poorly understood. Here, we combine experiments and long-term data to test how accurately published size-scaling relationships predict interactions between an economically and ecologically important predator-prey pair. We demonstrate that interaction strength is highly dependent on predator size, prey size, and prey density. We then used this relationship to predict plausible interaction strengths across ten years of data at five sites. Our analysis reveals that variation in body size accounts for up to 91% of the variation in interaction strength compared to density. However, predictions generated from even the closest size-scaling relationship from the literature underestimated the strength of interactions by a factor of 4.