Print version ISSN 0044-5967
CARVALHO, Karine Santana; BALCH, Jennifer and MOUTINHO, Paulo. Influences of leafcutter ant Atta spp. (Hymenoptera: Formicidae) on vegetation recovery after fire in Amazonian transitional forest. Acta Amaz. [online]. 2012, vol.42, n.1, pp. 81-88. ISSN 0044-5967. http://dx.doi.org/10.1590/S0044-59672012000100010.
In this study we investigated the role of leaf-cutting ants in the post-fire vegetation recovery. We hypothesized that a forest plot submitted to annual fire presents: (1) higher abundance of leaf-cutting ant nests; (2) higher removal of seeds; and (3) higher herbivory rates of leaf-cutting ants, when compared to the forest plots without fire (control). The leaf-cutting ant nests were sampled, mapped, and checked up (after 17 months) to register their activity and new colonies emerging from the plot. We made comparative experiments of seeds removal and seedlings herbivory in two 50 ha plots, one submitted to annual fire and another without fire. The abundance of leaf-cutting nests was higher in the plot submitted to fire than in the control plot. The species found were: Atta cephalotes, A. laevigata, and A. sexdens, being the latter the most abundant and the one that showed an increase of active colonies after 17 months. The plot submitted to fire showed a higher abundance of seeds removed by leaf-cutting ants than the control. While more than two leaves were ripped per seedling in the plot under fire, less than one was registered in the control plot. It was also observed that the average abundance of seedlings attacked by leaf-cutting ant in the fire plot was higher than in the plot without fire. This study shows that the leaf-cutting ants may reduce seed germination and seedling recruitment, affecting the reproductive success and the composition of vegetation recovering from fire. Alternatively, the leaf-cutting ants may also speed up the regeneration process of unpalatable plant species. In this sense, we may conclude that the presence of leaf-cutting may interfere in the species composition of post fire forest.
Keywords : leaf-cutting ants; herbivory; seed removal; forest regeneration.