Abstract
Extreme weather events perturb ecosystems and increasingly threaten biodiversity. Ecologists emphasize the need to forecast and mitigate the impacts of these incidents, which requires knowledge of how risk is distributed among species and environments, but the scale and unpredictability of extreme events complicates assessment. These challenges are compounded for large animals (‘megafauna’), which play crucial ecological roles but are hard to study. Traits such as body size, dispersal ability, and habitat affiliation are among the hypothesized determinants of animals’ vulnerability to natural hazards. However, it has rarely been possible to test these propositions or, more generally, to link short- and longer-term effects of weather-related disturbance. Here, we show how large herbivores and carnivores in Mozambique responded to Intense Tropical Cyclone Idai, the deadliest storm on record in Africa, across scales ranging from individual decisions in the hours after landfall to community-level responses nearly 20 months later. Animals occupying low-elevation habitats exhibited strong spatial responses to rising floodwaters. Body size predicted species’ subsequent numerical responses: small-bodied species exhibited the greatest population declines. We trace this sensitivity to limited mobility, which increased likelihood of death during the flood and constrained animals’ capacity to withstand food shortages afterward. Our results identify potentially general trait-based mechanisms underlying animal responses to severe weather and may help to inform strategies for wildlife conservation in a volatile climate.