Post-fire Regeneration Traits of Understorey Shrub Species Modulate Successional Responses to High Severity Fire in Mediterranean Pine Forests

Abstract Recurrent fires can impede the spontaneous recruitment capacity of pine forests. Empirical studies have suggested that this lead to a prolonged replacement forest by shrubland, especially if shrub species are pyrophytic. Model-based studies, however, post-fire succession under current climatic conditions will eventually tend towards dominance oaks high fire severity and recurrence. These previous modelling did not address role various regeneration traits understory species. Considering dichotomy obligate seeder vs. resprouter species, either or facultative resprouter, we hypothesized when shrubs present seeders, steadily occupy forest, whereas might compete with delay arrest succession. To test hypothesis, developed dynamic, cellular automaton model for simulating successional transitions in forests, including shrubs, pines oaks, stochastic regular frequency. Our results showed strong tendency oak as final state very reduced recurrence state, low yearly acorn input delaying dominance. Most relevantly, line our trend depended markedly on two types being delayed which extended shrub-dominated stage several centuries. simulation supported view type understorey should be key consideration restoration strategies aiming enhance resilience.