Navegando por Assunto "Frugivoria"

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Acesso aberto (Open Access)
Dispersão de sementes por sauins-de-coleira (Saguinus bicolor Spix, 1823; Primates:Cebidae): efeitos do padrão de deslocamento na formação de sombras de sementes
(Universidade Federal do Pará, 2012) LIMA, Roberto Guevara Ferreira; LOPES, Maria Aparecida; http://lattes.cnpq.br/3377799793942627
Quantifying the seed shadow generated by a disperser, which is the way seeds are distributed as a function of both the time seeds are retained in its digestive tract and of its ranging patterns through the habitat, is a key step to assess the impact of the seed disperser on structuring and functioning of plant populations and communities. This is the first study concerning the primate S. bicolor as a seed disperser and aimed to investigate the formation pattern of seed shadow in relation to the ranging patterns of the species. The moving of four groups of S. bicolor was monitored in three forest fragments in Manaus, Central Amazonia. The position of the animals in a trail grid was registered at five minutes intervals over the whole period of activity for five days a month over at least 15 months each group. The seed retention time were estimated by records of the time of ingestion, defecation and number of seeds of five species of cultivated fruits offered to four captive tamarins. Seed shadows were estimated by combining ranging patterns data with the seed retention time data. To each group, mean dispersal distance and the proportion of the home range used were obtained on a monthly basis, and their relation was accessed by a simple linear regression. The seed retention time ranged from 27 to 295 minutes (N = 394), with more than half of the seeds being retained up to two hours in the gut, and average number of seeds per defecation was 3,5 (± 3,7; N = 111). Probabilities of seed dispersal out of the vicinity of the parent plant are greater than 80% besides including distances greater than 1 km. For only two groups was verified a relation between the proportion of home range used and the dispersal distance, on a monthly basis, and one of them the explanatory power of the model reached less than 20%. The results indicate that S. bicolor disperses seeds effectively and, like other callitrichines, may contribute to the structuring and regeneration of forest ecosystems.
Acesso aberto (Open Access)
Interação mutualística entre aves frugívoras de sub-bosque e plantas no Parque Ecológico de Gunma, Santa Bárbara do Pará
(Universidade Federal do Pará, 2008) GOMES, Andreza de Lourdes Souza; JARDIM, Mário Augusto Gonçalves; http://lattes.cnpq.br/9596100367613471; MARCELIANO, Maria Luiza Videira; http://lattes.cnpq.br/4201678009295335
The ingestion of fruits by birds may represent a mutualistic relationship in which they use fruit as nutrient sources keeping intact the seeds. This interaction is described as networks and can present patterns or occurs at random. This study was designed to determine the network structure and the nestedness of interactions between understory bird assemblies and plants from primary and secondary forests at Gunma Ecological Park (PEG), located in the Amazonian region. From March to December of 2007, a total of ten expeditions were conducted for bird capture using mist nets and collection of feces samples for seeds identification. The results were used to determine the connectance, importance index and the nestedness of the mutualistic system. The nestedness in secondary forest was higher than in the primary forest, and the net interaction at Gunma Ecological Park was comprised by 37 species (birds and plants) with connectance of 18% and nestedness of 95%. Birds potentially seed dispersers were represented by 20 species, mainly by the families Pipridae, Tyrannidae, Turdidae and Thaurapidae. Dixiphia pipra was the most important seed disperser species in primary and secondary forest followed by Lipaugus vociferans in primary forest and Cyanerpes caerulens in secondary forest. A total of 17 plants species were found in the diet of birds. Miconia ciliata showed the highest importance index because it interacted with 16 bird species,followed by Phthirusa micrantha in primary forest and Euterpe Oleracea in secondary forest.