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Previous issue date: 2009-04-03 === Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior === ?The epiphytes are plants that use trees as support without being connected to the ground. The
epiphytes have wide geographical distribution and could be finding basically in most tropical
rain forest, representing 50% of the neotropical vascular flora. The families more
representative are Orchidaceae, Bromeliaceae, Araceae and Polypodiaceae. Despite the
increase in the number of studies on the epiphytism in Brazil, information on this guild in the
remaining forests of Rio de Janeiro state are still scarce. Thus, this study aimed to analyze the
composition, richness and guild structure on a forest situated between 500 and 1500 meters
over sea level (montana forest) in the Serra do ?rg?os National Park (RJ). In the 60 plots of
100 m2 (0.6 ha), all trees with DBH > 10.0 cm had their diameter and total height measured.
All epiphytes were identified and their abundances were estimated for each class of height
stipulated for the host trees. The relative frequencies of occurrence of species were calculated
for the area as a whole and for host trees as well as for the host trees classes of height, canopy
and trunk, and your value of importance calculated. Each species was classified according to
their ecological category. The horizontal distribution of species was analyzed using the
Morisita index and vertical by ?2 test. Relationship between the morphometric characteristics
of host trees and richness and abundance of epiphytes were performed by simple regression
analysis. We identified 84 species of epiphytes, in 28 genera and 9 families. The most
representative families were Bromeliaceae, Araceae and Polypodicaeae. In this area, the
epiphytes richness is considered high when compared with several studies in Brazil. The most
frequent species were Microgramma squamulosa, Pleopeltis pleopeltifolia and P.
hirsutissimum and a high number were considered rare species. Pleopeltis pleopeltifolia was
more frequent in host trees, followed by P. hirsutissimum and M. squamulosa. These species
also occurred in high frequencies in other studies, showing its wide geographical distribution
and its importance in the composition of this guild. The species with higher importance are
epiphytics P. hirsutissimum, P. pleopeltifolia and M. squamulosa, showing the high capacity
of these species to occupy the host trees. Most epiphytes in this area (56% of species) are
classified as holoepiphytes, as shown in other similar studies. For the horizontal distribution,
random distribution pattern were observed for basically all high abundance epiphytes,
indicating that this area has a wide availability of resources for the establishment of these
species. In vertical distribution, we observed a significant difference in the occupation of the
different classes of height of host trees for 53 of 84 species sampled. The highest occurrence
of epiphytes was observed in the canopy. There were significant and positive relationship
between height and total host trees with the richness and abundance of epiphytes, as well as
between DBH and richness and abundance of epiphytes. Thus, the epiphytes respond directly
to the structure of the forest where they are found, varying its parameters under different
ecological characteristics with structure of forest formation. === ?As ep?fitas s?o vegetais que, durante toda a sua vida ou em algum est?gio dela, vivem sobre as
?rvores, utilizando-as como suporte, sem estarem ligadas ao solo. As ep?fitas possuem uma
ampla distribui??o geogr?fica e s?o encontradas em praticamente todas as florestas ?midas,
representando cerca de 50% de toda flora vascular neotropical. As fam?lias mais
representativas s?o Orchidaceae, Bromeliaceae, Araceae e Polypodiaceae. Apesar do
incremento no n?mero de estudos sobre o epifitismo no Brasil, informa??es sobre esta guilda
nos remanescentes do Rio de Janeiro ainda s?o escassos. Desta forma, este estudo visou
analisar a composi??o, riqueza e a estrutura das ep?fitas vasculares em um trecho de Floresta
Ombr?fila Densa Montana do Parque Nacional da Serra dos ?rg?os (RJ). Foram demarcadas
60 parcelas de 100 m2 (0,6 ha), nas quais as ?rvores com DAP > 10,0 cm tiveram seu
di?metro e altura total mensurados. Todas as ep?fitas encontradas nos for?fitos foram
identificadas, tendo suas abund?ncias estimadas em cada classe de altura estipulada para os
for?fitos. As freq??ncias relativas de ocorr?ncia das esp?cies foram calculadas para a ?rea
como um todo, para os for?fitos e para as zonas de altura do for?fito, copa e fuste, al?m de
terem seu valor de import?ncia calculado. Cada esp?cie foi classificada de acordo com sua
categoria ecol?gica. A distribui??o horizontal das esp?cies foi analisada atrav?s do ?ndice de
Morisita e a vertical pelo teste de ?2 . Rela??es entre as caracter?sticas morfom?tricas do
for?fito e a riqueza e abund?ncia de ep?fitas foram efetuadas atrav?s da an?lise de regress?o
simples. Foram identificadas 84 esp?cies de ep?fitas, de 28 g?neros e nove fam?lias. As
fam?lias mais representativas foram Bromeliaceae, Araceae e Polypodicaeae. A riqueza de
ep?fitas nesta ?rea pode ser considerada alta quando comparada com diversos estudos
realizados no Brasil. As esp?cies mais freq?entes foram Microgramma squamulosa,
Pleopeltis pleopeltifolia e P. hirsutissimum, sendo consideradas raras a maioria das esp?cies.
Pleopeltis pleopeltifolia foi a mais frequente nos for?fitos, seguida de P. hirsutissimum e M.
squamulosa. As esp?cies com maiores valores de import?ncia epif?tica foram P.
hirsutissimum, P. pleopeltifolia e M. squamulosa, sendo clara a ampla capacidade de
ocupa??o dos for?fitos por estas esp?cies. A maioria das ep?fitas nesta ?rea (56% das
esp?cies) ? classificada como holoep?fitas, sendo este resultado semelhante a outros estudos.
Para a distribui??o horizontal, praticamente todas as ep?fitas tiveram um padr?o de
distribui??o aleat?rio, demonstrando, principalmente, que nesta ?rea h? uma ampla
disponibilidade de recursos para o estabelecimento destas esp?cies. Na distribui??o vertical,
foi observada uma diferen?a significativa na ocupa??o das classes de altura do for?fito para
53 esp?cies das 84 amostradas. A maior ocorr?ncia de ep?fitas foi observada na copa. Houve
rela??o significativa e positiva entre a dimens?o dos for?fitos e a abund?ncia e a riqueza de
ep?fitas. Assim, as ep?fitas responderam diretamente ? estrutura da floresta onde s?o
encontradas, variando seus par?metros ecol?gicos de acordo com a estrutura da forma??o
florestal.
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