Ecologia e historia natural das interações entre palmeiras, epifitas e frugivoros na região do pantanal matogrossense

AUTOR(ES)
DATA DE PUBLICAÇÃO

1992

RESUMO

The occurrence of vascular epiphytes and hemiepiphytes on three palm species in the Pantanal and Chapada dos Guimarses, Central Brazil was investigated. The sampling areas at the Pantanal were concentrated near Poconé and Barão de Melgaço. At Chapada dos Guimarães, sampling took place in the vicinity of the town, and in the area of influence of the Hydroelectric Dam of the Rio Manso. Censuses of the epiphytes and hemiepiphytes occurring on the individuaIs of each palm species were made. Measurements and characteristics of the palms, as well as the species, its characteristics, location and developmental state of the epiphytes were recorded. Direct observatios of the feeding behavior of diurnal and nocturnal visitors of fruiting strangling figtrees were also done. The three species of palms show similar architectural patterns. However, some specific atributes such as reduced crowns and old leaves hanging over the trunk seem to be associated with the reduction of the probability of the falI of diaspores onto those sites suitable for germination. Spines on the stems of the leaves may prevent its utilization as feeding roosts by birds and bats, also reducing the probability of epiphyte seeds to establish and develop over the trunk of a palmo These traits are considered as the most important in determining the differences in the occurrence frequency of epiphytes observed for the three palms. A total of ten species of epiphytes and hemiepiphytes was observed on the three palm species. Scheelea phalerata, which does not bear any of the adaptations cited above, exhibits the greatest richness and diversity of epiphytes. Acrocomia aculeata, which presents most of the adaptations, shows the lowest frequency of epiphytes. Epiphyte loads, apparently, do not cause severe damage to palms. However, strangling fig trees may eventually kill some. Fruiting fig trees attract many visitors. Twenty six species of frugivores were obseerved eating figs of two species of strangling fig trees. Birds and bats are the most important dispersers and, among these, bats of the genus Artibeus provide the best "quality of seed dispersal" for strangling fig trees. The system "palms-fig trees-bats/birds" seems to play an important role in the succession dynamics and colonization of open areas of some neotropical ecosystems, such as the Pantanal Matogrossense and the Venezuelan Llanos.

ASSUNTO(S)

ecologia vegetal

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