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Estrutura da taxocenose de Bromeliaceae em duas ?reas de restinga da Ilha da Marambaia, Ba?a de Sepetiba, RJ. / Taxocenose structure of Bromeliaceae of two restinga areas at Marambaia Island, Sepetiba Bay, RJ.Oliveira, Wagner Francisco de 09 March 2010 (has links)
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Previous issue date: 2010-03-09 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior, CAPES, Brasil. / Habitats characteristic of the Brazilian coast, the restingas are ecosystems associated with the
Atlantic Forest Domain and are characterized by having mesoclimatic conditions considered
extreme, and suffer from intense human pressure. Nevertheless, they have great biological
diversity, the Bromeliaceae being one of the most representative of these habitats. This study
aimed to evaluate the composition, richness and assemblage structure of Bromeliaceae in two
areas of restinga located on the island of Marambaia, Mangaratiba, RJ. We established 50
plots of 100 m2 on each of two areas: the Restinga of Praia da Arma??o (RPA) and the
Restinga da Praia Grande (RPG). These plots were placed in lines parallel to the beach with
10 meters apart. In each plot were recorded richness and abundance of epiphytic and
terrestrial bromeliads and measured the morphometric characteristics of the host tree, as well
as vertical and horizontal distributions of epiphytic species. We sampled 11 species of
bromeliads and three new records for Marambaia, bringing the richness of this locality for 21
species of Bromeliaceae, considered a high value of wealth. Most of the species is included on
some level of threat according to IUCN, which characterizes the Marambaia Island as an
important conservation site for the family. The Island had low similarity with other areas of
restinga of Rio de Janeiro and this can be attributed to its geographical location in relation to
these areas and the fact it is an island region. Neoregelia cruenta and Tillandsia stricta are the
most abundant and are the ones with the highest frequency of occurrence, which is directly
related to different reproductive strategies of these species. The specific physiological needs,
like dispersion and structural complexity of habitat caused if there were differences in the
occupation of phorophytes by epiphytic species. Already aggregated distribution of all species
is related to the mechanism of occupation of the environment used by plants and the quality of
different substrates provided by the environment and the host tree. In general, the species tend
to avoid the sampling units in accordance mainly with the heterogeneity of the habitat but,
however, tend to co-exist in phorophytes once occupied the height classes differently. In this
study, none of the morphometric parameters of the host tree explained the variations in the
parameters of assemblage richness and abundance of bromeliads, indicating that other
variables should better explain these relationships. / H?bitats caracter?sticos do litoral brasileiro, as restingas s?o ecossistemas associados ao
Dom?nio da Floresta Atl?ntica e caracterizam-se por apresentar condi??es mesoclim?ticas
consideradas extremas, al?m de sofrer com intensa a??o antr?pica. Apesar disso, possuem
grande diversidade biol?gica, sendo a fam?lia Bromeliaceae uma das mais representativas
nestes habitats. Este estudo visou avaliar a composi??o, riqueza e a estrutura da taxocenose de
Bromeliaceae em duas ?reas de restinga localizadas na Ilha da Marambaia, Mangaratiba, RJ.
Foram estabelecidas 50 parcelas de 100 m2 em cada uma das duas ?reas: a restinga da Praia da
Arma??o (RPA) e a restinga da Praia Grande (RPG). Estas parcelas foram alocadas em linhas
paralelas ? praia distando 10 m entre si. Em cada parcela foram registradas a riqueza e a
abund?ncia de brom?lias terrestres e ep?fitas e mensuradas as caracter?sticas morfom?tricas
dos for?fitos, e bem como as distribui??es vertical e horizontal das esp?cies ep?fitas. Foram
amostradas 11 esp?cies de brom?lias e tr?s novas ocorr?ncias para a Marambaia, elevando a
riqueza desta localidade para 21 esp?cies de Bromeliaceae, considerado um valor alto de
riqueza. A maior parte das esp?cies amostradas est? inclu?da em algum n?vel de amea?a
segundo a UICN, o que caracteriza a Ilha da Marambaia como um importante s?tio de
conserva??o para a fam?lia. A Ilha apresentou baixa similaridade com outras ?reas de restinga
do RJ e isto pode ser atribu?do a sua localiza??o geogr?fica em rela??o a estas ?reas e ao fato
de se tratar de uma regi?o insular. Neoregelia cruenta e Tillandsia stricta s?o as mais
abundantes e s?o as que possuem os maiores valores de freq??ncia de ocorr?ncia, fato que
est? diretamente relacionado ?s estrat?gias reprodutivas diferenciadas destas esp?cies. As
necessidades fisiol?gicas espec?ficas, forma de dispers?o e a complexidade estrutural do
h?bitat fizeram com que houvesse diferen?as na ocupa??o dos for?fitos pelas esp?cies
ep?fitas. J? a distribui??o agregada de todas as esp?cies est? relacionada ao mecanismo de
ocupa??o do ambiente utilizado pelas plantas e pela qualidade diferenciada dos substratos
oferecidos pelo ambiente e pelos for?fitos. De uma forma geral, as esp?cies tendem a se evitar
nas unidades amostrais de acordo, principalmente, com a heterogeneidade do h?bitat mas, no
entanto, tendem a co-existir nos for?fitos uma vez que ocupam as classes de altura de forma
diferenciada. Neste estudo, nenhum dos par?metros morfom?tricos do for?fito explicou as
varia??es dos par?metros de riqueza e abund?ncia da taxocenose de Bromeliaceae, indicando
que outras vari?veis devem explicar melhor essas rela??es.
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