Rapid recovery of ant-mediated seed dispersal service along secondary succession in a Caatinga dry forest

Abstract

Global expansion of secondary forests results from old-growth forest conversion to agriculture and livestock fields, followed by abandonment. Dry forests heavily rely on resprouting for rapid biomass recovery, but some species depend on seed dispersers. Ants are important seed dispersers in dry forests, as they can transport seeds over long distances, help species join the soil seed bank, and promote seed germination and seedling recruitment. We investigated seed-dispersing ant community, ant-seed interactions, and seed removal rates and distances along a Caatinga dry forest secondary succession using forest stands (8–54 years) after slash-and-burn agriculture and old-growth forest stands. We observed 796 interactions with 29 ant species and four plant species. About 26.51% were removals by 12 ant species, notably Dinoponera quadriceps and Ectatomma muticum, dispersing seeds up to 15 m. Only 14% of removed seeds reached nests while the rest were lost along foraging trails. Ant abundance of seed-dispersing ant community increased significantly with forest aboveground biomass, and both ant abundance and richness were significantly higher in secondary forest stands. Ant-seed interactions increased with biomass, being higher in old-growth forests. However, ant community composition, removal rates, and dispersal distances remained consistent across biomass and forest types. These findings may suggest that ant-mediated seed dispersal service quickly recovers during secondary succession, with implications for the dynamics of forest regeneration, given that ant-mediated seed dispersal is a prevalent and widespread phenomenon in the Caatinga dry forest.