Assembleias de peixes consumidoras de frutos e dispersoras de sementes em uma área de igapó da Amazônia Central, Brasil.

Abstract

In the Amazon there is an intense interaction of the floodplain with the fish community offering food, refuge area and seed dispersal. The dispersion of fruits carried out by fishes that is denominated as ichthyocoria, results in the displacement of the vegetal propagules away from the mother plant, because, as the seed moves away, it increases the chance of survival of the seedlings. It is estimated that frugivorous fish may be the dominant biotic seed dispersers in 300,000 km2 of floodplain forest, igapós and savannas along the basin, this process is common and essential for the maintenance of flooded forests, since the environment is subject to seasonal flooding throughout the year. The objective of this work was to identify species of fish from the forest of fruit-eating igapó and verify the viability of germination of the seeds found in the digestive tract and seeds found in nature. Samplings occurred in the months where there was the presence of igapó forest in Lake Tupé, in September 2016 until September 2017. The equipment used was two batteries of hammers, armed in two points of the forest of igapó, for 48 hours, with expenses every six hours. Biometry and the withdrawal of the digestive tract were performed in the field. For the diet were estimated the degree of repletion, frequency of occurrence of the items and the food index, the seeds present in the stomach and intestine of the fish were placed for sowing, together with the deriving of the mother plant, the percentage of germination was calculated, index of germination speed and the mean germination time. The data were tabulated and organized for use in an Anova One-way and t-test. A total of 878 individuals were collected, distributed in 4 orders, 20 families, 46 genera and 67 species. The most abundant food items were: fish, insects, crustaceans, plant material, fruits and seeds, material of animal and vegetable origin, where there is species consuming viable fruits for sowing was Auchenipterichthys longimanus, consuming 131 seeds of four botanical families, 59.54% obtained from the stomach and 40.46% from the intestine, the myrtacea Myrraria dubia, Eugenia inundata, Myrcia guianensis, the family Lecythidaceae, Gustavia augusta, the family Dilleniaceae, Doliocarpus aracaensis and the family Annoaceae Oxandra riedeliana, and other unidentified species. The results indicated in some species significant differences regarding their germination, but in others they did not present differences. It was concluded that only the species A. longimanus had intact seeds for germination and that this species is a potential seed disperser and thus can be considered a key species for the maintenance of the study area.