Understanding multi-hazard disturbance regimes as macro-ecological drivers of biodiversity

Natural disturbances shape ecosystems by redistributing biomass, resources, and mortality across space and time. While the ecological effects of individual disturbance types (e.g. fire, floods, storms) are well studied, a globally consistent assessment of how multiple disturbance types combine into long-term disturbance regimes, and how these regimes relate to biodiversity patterns, is still lacking at the macroecological scale.

Previous work (Kropf et al. in prep) presented 'hazomes,' a novel classification system of the earth based on hazard profiles, which is distinct from existing frameworks such as climate zones that categorize earth according to average conditions. Building up on this, we utilize a disturbance score based on eight different natural hazards (including heavy precipitation, earth quakes, tropical cyclones, cold spells, heat stress, coastal and river floods, water deficit, and wildfires), and their frequency of occurrence at different intensities. Unlike other commonly used climate descriptors such as mean temperature and precipitation, this approach captures the historical disturbance regimes ecosystems have been exposed to, providing a complementary perspective on the environmental drivers of biodiversity.

By correlating the disturbance index with biodiversity indicators, such as species richness across taxa, we find biome-specific disturbance-biodiversity relationships. While climate is understood to be a key driver of global biodiversity patterns, our research implies disturbance regimes may be key to understanding biodiversity patterns within areas of similar climatic conditions. These findings highlight disturbance regimes as an underexplored dimension of biogeography and suggest that biodiversity patterns reflect long-term exposure to disturbance, not only to climate. As climate change increasingly alters the frequency and intensity of natural hazards, understanding how ecosystems have been shaped by historical disturbance regimes is critical for anticipating future biodiversity responses.

 

Kropf, C. M., Hülsen, S., Stalhandske, Z., Hantson, S., Ward, P. J., Wens, M., Peleg, N., Bresch, D. N., & Steinmann, C. B. (in prep). Hazomes: Earth’s natural multi-hazard terrestrial disturbance regimes. EarthArXiv. https://eartharxiv.org/repository/view/10580/