In March 2019, Cyclone Idai, one of the most devastating tropical cyclones recorded in the Southern Hemisphere, struck Mozambique. This extreme weather event, characterized by torrential rains and winds exceeding 188 km/h, caused unprecedented flooding in the Gorongosa National Park, impacting a rich diversity of large mammals, from tiny oribis to massive elephants. This catastrophic event offers crucial insights into how large herbivores and carnivores respond to such intense natural disasters.
Researchers focused on the Gorongosa National Park, a biodiversity hotspot with a history of recovering from severe disruptions like the Mozambican Civil War. The park’s large mammals, including 13 herbivore species and predators like lions and African wild dogs, have adapted to regular flooding and other disturbances. However, Cyclone Idai presented an extraordinary challenge. This study is significant as there are few direct studies of large animals’ responses to cyclones, which are becoming more frequent and severe due to climate change.
The cyclone’s immediate impact was dramatic. Smaller, less mobile species like bushbuck struggled to escape the rapidly rising floodwaters, resulting in fatalities. In contrast, more prominent species like elephants exhibited greater resilience due to their size, mobility, and survival ability on lower-quality diets. Post-cyclone surveys revealed a distinct pattern: smaller species, closely associated with the floodplains, suffered significant population declines, while larger species, less dependent on these areas, showed population increases.
Cyclone Idai also led to significant changes in the animals’ diets. The flooding altered vegetation patterns, pushing herbivores towards higher ground and different food sources. Smaller species, less adaptable to these changes, faced more significant dietary challenges than their larger counterparts.
The study’s findings have far-reaching implications for wildlife conservation in the face of climate change. The varying responses among species underscore the importance of considering size, mobility, and habitat preference in predicting and managing the impacts of such extreme weather events on wildlife populations. This knowledge is crucial for developing strategies to protect vulnerable species and ecosystems from future climatic disturbances.
Researchers advocate for proactive measures, like moving animals from high-risk areas before storms and providing supplemental food post-disaster, to mitigate the ecological impacts of increasing climatic volatility. This study highlights the resilience and vulnerability of different species to extreme weather. It serves as a call to action for global research on cyclone ecology and the development of trait-based models to forecast the impacts of extreme events on terrestrial wildlife.
The study’s authors emphasize the need for continuous analysis of the impacts of extreme events, set against the shifting baselines of global climate change, to better understand and manage the intertwined fates of biodiversity and ecosystems in an increasingly unpredictable world.
Walker, R.H., Hutchinson, M.C., Becker, J.A. et al. Trait-based sensitivity of large mammals to a catastrophic tropical cyclone. Nature 623, 757–764 (2023). https://doi.org/10.1038/s41586-023-06722-0
