Portal de Periódicos da CAPES

Limitações bióticas afetando o recrutamento da palmeira Euterpe edulis em uma ilha continental da Mata Atlântica

2005; Linguagem: Inglês

2639-6459

Rodrigo F. Fadini,

Plant Diversity and Evolution

BIOTIC CONSTRAINS AFFECTING THE RECRUITMENT OF THE PALM Euterpe edulis IN A LAND-BRIDGE ISLAND OF THE ATLANTIC FOREST The aim of this study was to detect the possible limitations on the recruitment of the palmito (Euterpe edulis Martius) at the Ilha Anchieta State Park, Ubatuba, Sao Paulo, Brazil. The Island does not have resident populations of large frugivorous birds, that are among the dispersers of this palm, and, besides that, the Island possess an elevated density of seed predators and herbivores. One reproductive period was accompanied at the year of 2004, including fruit consumption, seed predation, seedling herbivory and population structure. The frugivory and the fruit consumption were accessed through the focal-tree method; the seed predation and herbivory through exclusion experiments using closed and semi-closed cages; and the population structure through monitoring of a fixed plot of 100 x 100 meters. The Serra do Mar State Park, situed at the Caraguatatuba city, was the control area because it was thought to possess a preserved fauna. The thrush Platycichla flavipes was the main visitor at the palmito trees, removing 73% and 96% of the total number of fruits consumed by all species at Anchieta Island and Caraguatatuba, respectively. However, the high density of this species together with its aggressive behavior could have contributed to decreasing the seed dispersal potential at the Anchieta Island. Large frugivorous birds were not frequent at the focal trees, whith only sporadic visits of Trogon viridis, Baryphthengus ruficapillus, Ramphastos dicolorus, Pteroglossus bailloni e Selenidera maculirostris. The exclusion experiments showed a higher seed predation at the Anchieta Island. 99,7% and 66,2% of the seeds were removed from the closed and semi-closed cages at Anchieta, while only 7,4% and 13,9% at Caraguatatuba. However, the population doesn’t seems to be limited by seed predators because more than 8,200 seedlings were found at the 1 hectare plot. But the experiment of herbivore exclusion showed a strong bootleneck, confirmed through a low population of youngs (only 19 individuals/hectare). The results show that the drastic reduction of the large frugivorous birds at Anchieta Island do not affect the plant demography, been the herbivory (probably by vertebrates) the main bootleneck for the palmito populaltion in this island.