EFFECTS OF ANNUAL FIRES ON THE PRODUCTION OF FLESHY FRUITS EATEN BY BIRDS IN A BRAZILIAN AMAZONIAN SAVANNA

This study describes changes in the numbers of plant species fruiting during six years in 1 ha of Amazonian savanna on the right bank of the Tapajos River, Brazil. The work was based on fleshy fruits from tree and shrub-layer species eaten by birds. The area was burned in the first two years, protected during the following two years and burned again in the last two years. The number of tree species fruiting did not differ significantly between years with and without fire. The number of shrub-layer species fruiting. was markedly reduced in years with fire, but the responses varied between species. Data on changes in shrub cover after two consecutive years of fire indicate that species also respond differently in terms of biomass lost due to fires. The two most abundant genera of shrubs, Miconia and Myrcia, had their cover reduced by up to 95% and 72% respectively. The area made available by the loss of shrubs was occupied mainly by the grass Paspalum carinatum. The fires and the decrease in the availability of fruits occurred during the season in which most species of birds breed. An interval of less than three years between fires is insufficient for shrub-layer species to recover.