Prescribed fire enhances seed removal by ants in a Neotropical savanna

Seed dispersal and predation by animals often drive plant regeneration. In tropical savannas, such as the Cerrado of Brazil, fire is also a key process in ecosystem dynamics, consuming the lower vegetation strata and killing wildlife, but how fire affects seed-animal interactions is virtually unknown. We investigated the effects of prescribed fires on the removal of diaspores from Miconia rubiginosa and sunflower Helianthus annuus in Cerrado from southeast Brazil. Using plots burned one month or one year before sampling and unburned controls, we assessed the effect of prescribed fire on microhabitat structure and diaspore removal by vertebrates and ants. Covered microhabitats experienced higher seed removal by vertebrates than open microhabitats, but microhabitat features did not influence seed removal by ants. Prescribed fire did not change the total amount of seed removal, and ants were responsible for most removals in burned and control plots. However, fire increased the importance of ants as agents of removal compared to vertebrates. These changes were probably mediated by changes in microhabitat cover. It is likely that species, whose seeds are often preyed upon by vertebrates, benefit from fire to escape predation, while the opposite would be true for those removed by granivorous ants. By changing microhabitats composition and frequency of seed removal by different agents, fire may create pulses of opportunities for certain plant species to increase their populations and enlarge their spatial distribution, while constraining others. However, how different fire intensities and frequencies influence seed fate of different species is still to be investigated. Abstract in Portuguese is available with online material.