A structured inventory of spiders (Arachnida, Araneae) in natural and artificial forest gaps at Porto Urucu, Western Brazilian Amazonia

A preliminary survey of the spider fauna in natural and artificial forest gap formations at “Porto Urucu”, a petroleum/natural gas production facility in the Urucu river basin, Coari, Amazonas, Brazil is presented. Sampling was conducted both occasionally and using a protocol composed of a suite of techniques: beating trays (32 samples), nocturnal manual samplings (48), sweeping nets (16), Winkler extractors (24), and pitfall traps (120). A total of 4201 spiders, belonging to 43 families and 393 morphospecies, were collected during the dry season, in July, 2003. Excluding the occasional samples, the observed richness was 357 species. In a performance test of seven species richness estimators, the Incidence Based Coverage Estimator (ICE) was the best fit estimator, with 639 estimated species. To evaluate differences in species richness associated with natural and artificial gaps, samples from between the center of the gaps up to 300 meters inside the adjacent forest matrix were compared through the inspection of the confidence intervals of individual-based rarefaction curves for each treatment. The observed species richness was significantly higher in natural gaps combined with adjacent forest than in the artificial gaps combined with adjacent forest. Moreover, a community similarity analysis between the fauna collected under both treatments demonstrated that there were considerable differences in species composition. The significantly higher abundance of Lycosidae in artificial gap forest is explained by the presence of herbaceous vegetation in the gaps themselves. Ctenidae was significantly more abundant in the natural gap forest, probable due to the increase of shelter availability provided by the fallen trees in the gaps themselves. Both families are identified as potential indicators of environmental change related to the establishment or recovery of artificial gaps in the study area.

Regeneración natural de nueve especies maderables en un bosque intervenido de la Amazonia Boliviana

Un aspecto fundamental del manejo forestal sostenible, es el mantenimiento de la regeneración natural en los bosques aprovechados. A corto y largo plazo, el aprovechamiento forestal tiene varias consecuencias, sobre la regeneración natural de las especies forestales. Esta investigación, compara la abundancia de la regeneración natural y la distribución espacial de plántulas de nueve especies maderables, entre un bosque aprovechado y un testigo. La abundancia y estructura espacial, fue determinada mediante 55 parcelas de muestreo anidadas (20 x 20 m, 10 x 10 m), estas fueron distribuidas en 180 hectáreas en cada condición de bosque evaluado. Dentro de las parcelas de 10 x 10 m, se registraron las categorías: plántula, brinzal y latizal. En las parcelas de 20 x 20, se midieron los árboles semilleros con DAP > 20 cm. En bosque aprovechado C. racemosa, T. altissima y A. lecointei mostraron mayor abundancia total. Según categorías de regeneración, la abundancia de P. corymbosum resultó mayor en bosque aprovechado; pero en las especies C. racemosa, T. altissima, D. odorata y C. micrantha fue mayor en el bosque testigo. La abundancia de A. lecointei, P. heterophylla y Virola sp. no difirió entre sitios. Espacialmente, solo A. lecointei y Virola sp mostraron patrones diferentes entre condiciones de bosque estudiados. Estos resultados, permiten concluir que el aprovechamiento forestal, no modifica significativamente la abundancia y estructura espacial de la regeneración de todas las especies forestales, por lo que, las intensidades de extracción moderada no comprometería el potencial de la regeneración natural en bosques manejados.

Avaliação da diversidade alfa de Passalidae (Coleoptera: Scarabaeoidea) na Amazônia Colombiana (Parque Nacional Natural La Paya, Putumayo)

Este trabalho apresenta um inventário da fauna de Passalidae da região sudeste do Parque Nacional Natural La Paya, sendo a primeira coleta deste grupo de insetos para o Estado colombiano de Putumayo. As coletas, de indivíduos adultos, foram feitas durante os dias 9 a 16 de fevereiro de 2008, em percursos livres, nos quais foram revisados 80 troncos em decomposição. A porcentagem de troncos colonizados por passalídeos foi de 40%, nos quais foram coletados 225 indivíduos pertencentes a duas tribos, quatro gêneros e 16 espécies, representando entre 73-96% da riqueza estimada por curvas de acumulação de espécies. A tribo com maior riqueza foi Passalini, enquanto o gênero com maior diversidade foi Passalus Fabricius, 1792 com 12 espécies. A diversidade local do grupo estudado é alta, em comparação a outros registros obtidos na região neotropical.

Tree communities of white-sand and terra-firme forests of the upper Rio Negro

The high tree diversity and vast extent of Amazonian forests challenge our understanding of how tree species abundance and composition varies across this region. Information about these parameters, usually obtained from tree inventories plots, is essential for revealing patterns of tree diversity. Numerous tree inventories plots have been established in Amazonia, yet, tree species composition and diversity of white-sand and terra-firme forests of the upper Rio Negro still remain poorly understood. Here, we present data from eight new one-hectare tree inventories plots established in the upper Rio Negro; four of which were located in white-sand forests and four in terra-firme forests. Overall, we registered 4703 trees > 10 cm of diameter at breast height. These trees belong to 49 families, 215 genera, and 603 species. We found that tree communities of terra-firme and white-sand forests in the upper Rio Negro significantly differ from each other in their species composition. Tree communities of white-sand forests show a higher floristic similarity and lower diversity than those of terra-firme forests. We argue that mechanisms driving differences between tree communities of white-sand and terra-firme forests are related to habitat size, which ultimately influences large-scale and long-term evolutionary processes.

Does nitrogen availability have greater control over the formation of tropical heath forests than water stress?A hypothesis based on nitrogen isotope ratios

Global scale analyses of soil and foliage δ15N have found positive relationships between δ15N and ecosystem N loss (suggesting an open N cycle) and a negative relationship between δ15N and water availability. We show here that soils and leaves from tropical heath forests are depleted in 15N relative to 'typical' forests suggesting that they have a tight N cycle and are therefore limited by N rather than by, often suggested, water availability.

Brazil nuts: determination of natural elements and aflatoxin

A study was carried out to evaluate the association of levels of radioactivity, selenium and aflatoxin in shelled Brazil nuts, which were classified in different sizes, for export. The selenium determinations were performed by inductively coupled plasma optical emission spectrometry (LOQ = 3.0 µg g-1), and aflatoxins were detected by Liquid chromatography-mass spectrometry (LOQ = 0.85 µg kg-1), recovery rates were between 92 and 100%. Radioactivity was measured by high-resolution gamma spectrometry. The selenium mean concentration was (22.7 ± 7.4) µg g-1. (n = 30). Mean activities determined for the following radium isotopes were: 15.77 Bq kg-1 for 224Ra, 104.8 Bq kg-1 for 226Ra and 99.48 Bq kg-1 for 228Ra. For 226Ra, the levels did not vary significantly with nut sizes, although such differences were observed for 224Ra and 228Ra. There was no statistically significant association between the level of selenium and the activity of radionuclides, however, there was correlation between the radionuclides. Aflatoxins above the quantification limit were not found.

Eficiência do nim (Azadirachta indica A. Juss) como barreira natural ao ataque de Hypsipyla grandella (Zeller) (Lepidoptera: Pyralidae) sobre o mogno (Swietenia macrophylla King)

A eficiência da espécie Azadirachta indica como barreira natural ao ataque da Hypsipyla grandella sobre o mogno em diferentes arranjos e densidades de plantio foi, avaliada. O estudo foi realizado numa área de pastagem degradada em Vigia, PA. O delineamento experimental utilizado foi em blocos ao acaso em esquema de parcelas subdivididas no tempo, com cinco repetições, sendo as formas de cultivo do mogno as parcelas, e as épocas de avaliação (meses) as subparcelas. A barreira natural formada pelo nim não evitou o ataque de H. grandella sobre o mogno, mas retardou e minimizou o ataque em plantios mistos. Para o maior controle do ataque de H. grandella, o mogno não deve ser plantado simultaneamente com o nim, mas um ano após o plantio do nim, quando este apresenta mais de três metros de altura, formando uma barreira natural mais eficaz ao ataque desta praga.

Free-standing multilayered membranes based on graphene and natural polymers for biomedical applications

Dissertação de mestrado integrado em Engenharia Biomédica (área de especialização em Biomateriais, Reabilitação e Biomecânica)

The mineralogy and chemistry of the German and Portuguese tiles used to face a historic building in the Amazon region and their natural susceptibility to tropical weathering

During the 19th century, the most prominent buildings of the city of Belém were faced entirely with tiles manufactured in Portugal and Germany, which now exhibit distinct degrees of degradation. The Pinho mansion is one of the most important of these buildings and was selected for the investigation of the action of the tropical Amazonian climate on the degradation of the tiles. To achieve this objective, the tiles were mapped for organic and inorganic degradation, and samples were collected for analysis. The minerals were determined by XRD, the chemical composition by classical wet methods and SEM/EDS, and the microorganisms under the microscope. The results show that the German and Portuguese tiles are quite different in their composition. While both ceramic bodies are composed of SiO2 and Al2O3, CaO was found only in the Portuguese tile. The low Na2O and K2O contents indicate the addition of materials to reduce the fusion temperature. SiO2 and PbO are the main constituents of the glaze, with CoO and FeO being added as pigment. The ceramic body of the German tiles is constituted of quartz, mullite, and cristobalite, in contrast with the Portuguese tiles, which are made of quartz, gehlenite, diopside, calcite, and feldspars. The glazes are XRD-amorphous. The chemical and mineralogical differences between the German and Portuguese tiles indicate that they were produced from different raw materials under distinct thermal processes. The most prominent weathering-related modifications are the thin layers (German tiles), oxidation stains, dark stains, the detachment of the tile (Portuguese tiles), loss of the glaze and powdering of the ceramic body (Portuguese tiles) through the establishment of Cyanophyta and Bacillariophyta.. The distinct degradation patterns of the tiles exposed to the tropical Amazon climate are a consequence of their distinct mineralogy and chemistry.

Utilização de gás natural comprimido em veículos pesados de passageiros

Dissertação de mestrado em Engenharia Mecânica

Natural diet and feeding habits of a freshwater prawn (Macrobrachium carcinus: Crustacea, Decapoda) in the estuary of the Amazon River

Macrobrachium carcinus is a Brazilian native prawn with recognized potential for use in aquaculture activities. However, there is little information about the natural diet and feeding habits of this species. The aim of this study was the identification of the diet items of M. carcinus based on the analysis of the stomach contents. Specimens were collected in the Amazon River estuary between January 2009 and January 2010. The stomach analysis was carried out by using the frequency of occurrence (FO), methods of points (MP) and feeding index (FI). It was observed that prawns fed on detritus, animals and plant fragments as the most important food items. Sediment accounted for the main stomach content, accounting for 43.2% by the MP, 44.9% by FI and 100% by the FO. Sexual differences in feeding preferences were not found in this study, and seasonal differences in the frequency of items ingested by M. carcinus were not observed. The results indicated that M. carcinus can be considered omnivorous species, but with an important carnivorous component, similar to that found in other Macrobrachium species.

Updated List and identification key of 219 tree species of white sand forests of the Allpahuayo Mishana National Reserve, Loreto, Peru

White sand forests, although low in nutrients, are characterized not only by several endemic species of plants but also by several monodominant species. In general, plants in this forest have noticeably thin stems. The aim of this work was to elaborate a parallel dichotomous key for the identification of Angiosperm tree species occurring on white sand forests at the Allpahuayo Mishana National Reserve, Loreto, Peru. We compiled a list of species from several publications in order to have the most comprehensive list of species that occur on white sand forest. We found 219 species of Angiosperm, the more abundant species were Pachira brevipes (26.27%), Caraipa utilis (17.90%), Dicymbe uaiparuensis (13.27%), Dendropanax umbellatus (3.28%), Sloanea spathulata (2.52%), Ternstroemia klugiana (2.30%), Haploclathra cordata (2.28%), Parkia igneiflora (1.20%), Emmotum floribundum (1.06%), Ravenia biramosa (1.04%) among others. Most species of white sand forests can be distinguished using characteristics of stems, branches and leaves. This key is very useful for the development of floristic inventories and related projects on white sand forests from Allpahuayo Mishana National Reserve.

Litterfall production in intact and selectively logged forests in southern of Amazonia as a function of basal area of vegetation and plant density

Nutrient recycling in the forest is linked to the production and decomposition of litter, which are essential processes for forest maintenance, especially in regions of nutritionally poor soils. Human interventions in forest such as selecttive logging may have strong impacts on these processes. The objectives of this study were to estimate litterfall production and evaluate the influence of environmental factors (basal area of vegetation, plant density, canopy cover, and soil physicochemical properties) and anthropogenic factors (post-management age and exploited basal area) on this production, in areas of intact and exploited forest in southern Amazonia, located in the northern parts of Mato Grosso state. This study was conducted at five locations and the average annual production of litterfall was 10.6 Mg ha-1 year-1, higher than the values for the Amazon rainforest. There were differences in litterfall productions between study locations. Effects of historical logging intensity on litterfall production were not significant. Effects of basal area of vegetation and tree density on litterfall production were observed, highlighting the importance of local vegetation characteristics in litterfall production. This study demonstrated areas of transition between the Amazonia-Cerrado tend to have a higher litterfall production than Cerrado and Amazonia regions, and this information is important for a better understanding of the dynamics of nutrient and carbon cycling in these transition regions.

Similar understorey structure in spite of edaphic and floristic dissimilarity in Amazonian forests

Forest structure determines light availability for understorey plants. The structure of lowland Amazonian forests is known to vary over long edaphic gradients, but whether more subtle edaphic variation also affects forest structure has not beenresolved. In western Amazonia, the majority of non-flooded forests grow on soils derived either from relatively fertile sediments of the Pebas Formation or from poorer sediments of the Nauta Formation. The objective of this study was to compare structure and light availability in the understorey of forests growing on these two geological formations. We measured canopy openness and tree stem densities in three size classes in northeastern Peru in a total of 275 study points in old-growth terra firme forests representing the two geological formations. We also documented variation in floristic composition (ferns, lycophytes and the palm Iriartea deltoidea) and used Landsat TM satellite image information to model the forest structural and floristic features over a larger area. The floristic compositions of forests on the two formations were clearly different, and this could also be modelled with the satellite imagery. In contrast, the field observations of forest structure gave only a weak indication that forests on the Nauta Formation might be denser than those on the Pebas Formation. The modelling of forest structural features with satellite imagery did not support this result. Our results indicate that the structure of forest understorey varies much less than floristic composition does over the studied edaphic difference.