Biotic-drivers of seedling establishment in Neotropical savannas: selective granivory and seedling herbivory by leaf-cutter ants as an ecological filter

Herbivory has been shown to have prominent top-down effects on vegetation in Paleotropical savannas, where consumers of early stages of life history act as demographic bottlenecks. Such impact has been largely ignored in Neotropical savannas, however, despite insect consumption being linked to reduced recruitment of woody species.
We hypothesize that Atta leaf-cutter ants – the prevalent herbivores in the Neotropics – alter the establishment of woody plant seedlings in the Brazilian Cerrado by reducing seed availability and seedling survival. We also hypothesize that the demographic effects will be species-specific.
To test these hypotheses, we experimentally (i) compared seed removal in areas with and without Atta foraging and (ii) compared the survivorship of seedlings exposed to or protected from Atta foraging. Both experiments were performed with the same common Cerrado species which allowed us to evaluate the potential net effects of consumers at the population and community leve...