Estrutura e riqueza de hepáticas (Marchantiophyta) epifíticas em áreas fragmentadas de Cerrado com borda natural e antrópica
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2010-06-08
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Universidade Federal de Goiás
Resumo
The damage caused by the proliferation of edge in forest cover, referred to as edge effects
are extensive, may occur over large spatial scales influencing species composition,
structure and ecological processes in boundaries of ecosystems. However, studies have
shown highly variable response patterns of the taxonomic group studied in relation to the
landscape. In this context, bryophytes are an ideal group for assessing the impacts of
habitat fragmentation because of their sensitivity to changes in microclimate resulting from
the loss and degradation of habitats. This study aimed to assess how the communities from
epiphytes liverworts (Marchantiophyta) respond to forest edges originated of
anthropogenic fragmentation and the natural edges in the grassland-forest transitions in the
Cerrado. The study areas are located in the Parque Estadual da Serra de Caldas Novas and
in surroundings, including Caldas Novas and Rio Quente cities, state of Goiás. We
sampled three habitat types: (1) forest valleys on the slopes of the mountain with abrupt
transitions to rocky fields, (2) edge (0 to 10 m) and (3) interior (100 to 110 m) of
semideciduous forest fragments surrounded by a matrix of grass. These were the three
treatments considered in the analysis, designated for: BN (natural edge), BA
(anthropogenic edge) and IF (interior of the fragment). Four plots (10´10m) were
randomly delimited along transects (10´200m) for each treatment in each area. For the
sampling in the plots, were selected all trees with perimeter at breast height (PAP) ≥ 20 cm
and with minimum coverage of bryophytes of 300cm2. For the quantitative survey of
liverworts the interception line method was utilized. Between vegetation parameters, the
number of individual trees had positive relationship with richness and abundance in
liverworts, whereas basal area had positive relationship with coverage demonstrating the
importance of these parameters in liverworts community struture. The richness of
liverworts was higher in natural and anthropogenic edges in relation to the interior of the
fragments demonstrating that the type of edges do not seem to influence the richness of the
liverworts and this increased richness at the edges may be related with the intermediate
disturbance hypothesis. Coverage of liverworts was higher in BN than BA, while the BN
had distinct floristic composition of BA and IF, that may reflect the environmental
peculiarities (moisture, temperature and solar radiation). The evaluation of edge effects on
life forms and preference of habits shows some important trends to understand the
responses of the liverworts, mainly due to increased frequency of pendant life-forms with low tolerance to desiccation and higher frequency of epiphytes shadow in natural edges.
This indicates that the use of functional groups in monitoring the effects of fragmentation
can provide a large generalization for the evaluation of responses the liverworts.
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ASSAD, Lailah Luvizoto. Structure and richness of the epiphytic liverworts (Marchantiophyta) in fragmented areas of Cerrado with natural edge and anthropogenic. 2010. 78 f. Dissertação (Mestrado em Ciências Biológicas - Biologia) - Universidade Federal de Goiás, Goiânia, 2010.