Comparing the influence of large- and small-scale disturbances on forest heterogeneity: A simulation study for mangroves

• Disturbances had significant homogenizing effects on the spatial forest structure.
• Hurricanes lead to a temporal heterogenization in the forest structure.
• Small frequent gaps did not contribute to additional temporal heterogeneity.
• Biomass is not sufficient to characterize forest structure.
• Simulation results were integrated into a conceptual model for mangrove forests.

Disturbances play a crucial role in various forest ecosystems and represent major shaping forces in forest succession and spatio-temporal processes. In this study, we simulated different disturbance regimes using the individual-based mangrove forest model KiWi. Frequent small-scaled gaps caused by lightning strikes and rare medium-sized patches caused by hurricanes were produced with varying size, severity and frequency. Additionally, a mixed regime including both lightning strikes and hurricanes was simulated. All three scenarios produced the same tree mortality rate over the simulation periods. We analyzed the temporal and spatial variations in these disturbances, taking into account their homogenizing or heterogenizing effects on the forest structure of a simulated area of 25 ha. All disturbance regimes produced significantly more homogenizing effects on the spatial forest structure than an undisturbed scenario. The hurricane regime produced a temporal heterogenization of the forest structure, while the small-scaled frequent lightning strike gaps were not able to contribute to additional heterogeneity. This shows that the explicit implementation of the disturbances generates different forest structures. The simulation results were integrated into an existing conceptual model for mangrove forest dynamics.