Dispersão de sementes por Atta robusta Borgmeier, 1939 (Hymenoptera: Formicidae) na restinga da Ilha de Guriri- ES

• Autor(a) principal: Teixeira, Marcos da Cunha
• Data de Publicação: 2007
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/949
• topic: Dispersão de sementes; Atta robusta; Formigas; Restinga; Seeds dispersal; Atta robusta; Ants; Restinga; CNPQ::CIENCIAS BIOLOGICAS::ECOLOGIA

This thesis characterized the use of fruits and seeds by Atta robusta Borgmeier, 1939, and the effects on the germination, seeds predation and seedlings survival. Fieldwork was carried out in the Guriri Island (18°43 S, 39°45 W), São Mateus, Espírito Santo State, Southeast Brazil, from March 2005 to March 2006. A. robusta was foraging 35 species of fruits and seeds during the studies period. First the ants carriy the seeds into their nests. After some time the ants remove the seeds from their nests onto the soil surface, promoting the secondary seeds dispersal. The seeds are placed on refusal piles on the soil. The results showed smaller seeds species are removed through longer distances. These results also verified what kinds of seeds were loaded. The results suggest the seeds load by A. robusta importance as secondary seed dispersal. Seeds manipulated by A. robusta germinated more efficiently than non-manipulated seeds. On the nests, seeds predation was smaller and the seedlings density higher in comparison with other species of adult plants. The higher germination index may be, possibly, a consequence of the pulp removal by A. robusta. This procedure reduced the pathogenic fungus and promoted the seeds scarification, increasing the water absorbance. The minor seeds predation over the nests can attributed to smaller predator activities at this sites where the seed density is smaller. The differences on the seedlings survival can be due to density effects. Possibly, the higher nutrient concentrations beneficiate the seedlings. These results were also registered by A. laevigata studies in Amazon forests. We concluded that A. robusta is an important instrument in seeds secondary dispersal as well as it can play a significant role on Restinga Forests ecosystems dynamic.