Seed dispersal as a backup system to resprouting and seeding during post-fire regeneration

Plant populations can recover from wildfires through resprouting (resprouters), recruiting from in situ surviving seed banks (seeders) or recolonization via seed dispersal. However, it is unclear how complementary these mechanisms can be, especially whether and how specific seed dispersal syndromes are associated with resprouter or seeder potential. In particular, it is unknown whether the occurrence of traits that facilitate seed dispersal and post-fire recolonization are disproportionately frequent among plants that lack other fire-coping strategies (i.e. colonizers).

Here, we compiled information on the presence of post-fire regeneration mechanisms - resprouting potential, seeding capacity and presence of traits that facilitate seed dispersal - for 705 species from the European Mediterranean Basin. Three-way contingency tables were built and analysed using log-linear models to assess associations between the three mechanisms.

We found a negative association between resprouting and seeding capacity, and observed that these mechanisms were independent of having any traits related to seed dispersal. However, traits facilitating endozoochory (fleshy fruits) were more common among resprouters than expected by chance.

Our results show that traits enhancing seed dispersal are widespread among post-fire resprouters and seeding species in the Mediterranean Basin flora. We conclude that seed dispersal traits are mostly an independent backup system assisting the recovery of burned sites rather than an alternative to resprouting or post-fire seeding.