Hurricane and fire effects in savanna-forest landscapes

Sequential large-scale disturbances may produce§interacting effects that differ from those predicted§for each disturbance in isolation. These non-additive§effects can strongly influence the composition and§structure of plant communities. Hurricanes and§natural lightning-season fires are large-scale,§frequent disturbances in savanna-forest landscapes of§the southeastern US. Passmore develops a predictive§conceptual model for interacting disturbances. She§predicts that hurricane-fire interactions may§influence ecotones between savannas and forests by§changing species composition and structure. Based on§predictions, Passmore implemented an experimental§study in savanna-forest ecotone to test hypotheses of§interactive effects. She hypothesized that effects of§lightning-season fires differ when fires occur alone§compared to when fires are preceded by hurricanes.§Disturbance interactions reduced stem density and§species richness of woody plants in the field study.§Thus, hurricane-fire interactions influence§vegetation structure in savanna-forest ecotones. §Furthermore, over longer time scales interactions may§result in landscape-level changes in southeastern§savanna-forest ecosystems.