Interações entre diásporos e formigas em floresta secundária na Ilha da Marambaia - Mangaratiba / RJ, Brasil

Abstract

Among the various taxa interacting, ants and angiosperms have a long evolutionary history together, starting from the Cretaceous period, which currently range from antagonistic to mutualistic relationships. Interactions between ants and diaspores (plant disperser unit) result in many benefits for the plants, and the dispersal of its seeds. Our goal was to identify which species of ants interact with the species of diaspores in secondary forest on Ilha da Marambaia, RJ . In addition to identifying the participants of the network of interactions, we sought to determine the influence of factors such as the amount of available resources in the study area and climatic variables on total interactions (Chapter 1). We selected four species of diaspores in order to determine how many are removed, the final site of deposition and removal distance of these diaspores (Chapter 2). We recorded 675 interactions between 43 ant species and 22 plant species. Pheidole sp4, Pheidole radoszkowskii and Wasmannia auropunctata were more common species in interactions. Among the plants, Guarea guidonia and Miconia prasina receive the greatest amount of interaction. The abiotic variables, such as light and temperature, do not change the number of interactions. The availability of resources in the environment does not influence, but the wealth of available propagules leads to larger amounts of records of interactions. The species show, mostly, considerable removal rates after falling on the ground. However, the distances carried by ants were short, reaching a maximum of four meters and the final destination of deposition of diaspores were the nests, usually. Ants play an important role in plant breeding stage. Rapid removal of the seeds or cleaning them reduces the chances of attack by pathogens, favoring germination. Even shortremoved distances by ants are sufficient to deprive the diaspores of large areas of high predation and competition. The deposition of the fruits in the nests can be determined as a direct scattering, since some species germinate more near nests than in adjacent areas without them. The nesting areas have different characteristics, such as soil penetrability and amount of available nutrients in soil, favoring the growth of seedlings in these areas. Ants are thus possible agents of a dispersion process and its abundance in forest soils may lead to believe in the strength that these species have on the species of diaspores in forest environments.