RESUMO
This study describes the tree and shrub component of the Atlantic Forest on the slopes of Marambaia Island, RJ. It further evaluates which species are found at threatened species lists and the similarity that the studied forest component has with other nearby locations with similar vegetation. Data gathering relied on the joint effort of arbitrary walks and sampling units known as Transect. The same sampling criterion was applied at both approaches (DBH greater than or equal to 5 cm). A similarity analysis, followed by a Cluster analysis, was used to compare the studied vegetation component. Similarity calculations were based in the Bray-Curtis coefficient. We detected a total of 235 species. These are divided in 134 genera and 52 families. The richest families are Myrtaceae (38 spp.), Fabaceae (20 spp.) and Rubiaceae (20 spp.). The richest genera are Eugenia (16 spp.), Myrcia (8 spp.) and Ocotea (6 spp.). Nineteen of the detected species are currently listed as threatened and the studied forest component is mostly resembled to the vegetation at Rio Bonito (RJ). Our evidence shows that the evaluated tree and shrub layer seems to be well preserved and represents an important area for conservational efforts. The results additionally indicate that this vegetation seems to have a greater floristic resemblance to drier and further locations, rather than to more humid and close ones.
Este estudo descreve a florística do componente arbóreo e arbustivo da Floresta Atlântica sobre as encostas da Ilha da Marambaia, RJ. Também são avaliadas quais das espécies encontradas constam em listas de espécies ameaçadas e qual a semelhança deste componente da vegetação com locais próximos cobertos pelo mesmo tipo de vegetação. A coleta de dados se valeu do esforço conjunto de caminhadas arbitrárias e de unidades amostrais conhecidas como "Transect". O critério de inclusão na amostragem foi o mesmo para ambos os métodos (DAP igual ou maior a 5 cm). O componente estudado foi comparado a outras áreas através de uma análise de similaridade, seguida de um dendrograma. Os cálculos de similaridade foram baseados no coeficiente de Bray-Curtis. Detectamos, ao todo, 235 espécies, distribuídas em 134 gêneros e 52 famílias. As famílias mais ricas são Myrtaceae (38 spp.), Fabaceae (20 spp.) e Rubiaceae (20 spp.), enquanto os gêneros mais ricos são Eugenia (16 spp.), Myrcia (8 spp.) e Ocotea (6 spp.). Dezenove das espécies detectadas constam em listas de espécies ameaçadas de extinção e o componente estudado tem maior similaridade com a floresta em Rio Bonito (RJ). As evidências mostram que a vegetação estudada parece estar bem preservada e representa uma área importante para esforços conservacionistas. Os resultados indicam ainda que o remanescente florestal em questão aparenta ser mais semelhante a locais mais secos e distantes do que próximos e úmidos.
RESUMO
The stingless bees are important flowers visitors of several plant species, due to their feeding habits and foraging behavior, constituting an important group to maintain biodiversity and the dynamics of tropical communities. Among stingless bees, Tetragonisca angustula is widely distributed in tropical habitats, and has been considered an important pollinator of different plant families. To support a rational economic use of this group, there is a need to characterize the plant species that represent important sources as part of their diet, as preferred, alternative or casual food sources. The aim of this survey was to distinguish the plant species that T. angustula visited most often. The study was undertaken in four regions of the Atlantic Rainforest in Rio de Janeiro state (Brazil) over a year from March 2008 to February 2009. For this, we collected bees, flowering plants and bee pollen loads from the four sites, and evaluated pollen morphology in the laboratory. Field observations showed the presence of plants belonging to ten different families and pollen loads showed the presence of pollen types belonging to 26 plant families. There were strong differences between pollen types, especially regarding pollen grain shape. The present survey suggests a high value of these plant species as trophic resources for the T. angustula in the understory of Atlantic Rainforest. Changes in these fragments of this forest may compromise the availability of resources for Tetragonisca angustula species and other stingless bees.