Navegando por Assunto "Floresta tropical"

Agora exibindo 1 - 11 de 11

Acesso aberto (Open Access)
Avaliação dos efeitos da plantação de palmas (Elaeis guineensis) na conservação de anuros na Amazônia oriental
(Universidade Federal do Pará, 2017-06-30) CORREA, Fabricio Simões; JUEN, Leandro; http://lattes.cnpq.br/1369357248133029; COSTA, Maria Cristina dos Santos; http://lattes.cnpq.br/1580962389416378
In this thesis, we analyzed the effects of oil palm cultivation (Elaeis guineensis) on taxonomic and functional diversity of anurans in the eastern Amazon. In addition, we analyzed the response of anurans to environmental variation in oil palm plantations and surrounding forests. We surveyed for the presence of anurans in April 2012, 2015 and 2016, in 2100 m² plots through visual and acoustic searches. In April 2016, we also measured microclimatic (air temperature and humidity) and habitat structural variables (water body width and depth, leaf litter depth, canopy openness and number of trees) in both habitat types. We found higher functional diversity and species richness in forests, with difference in species composition and functional characters distribution between forests and oil palm plantations. Water body depth and width positively affected species richness and number of individuals, while water body depth and diurnal temperature influenced species composition in oil palm plantations. Only number of individuals was positively affected by diurnal temperature and nocturnal humidity in forests, while species composition and richness were not affected by any environmental variable in this habitat type. Our results make clear that conversion of forests to oil palm plantations negatively affects anurans taxonomic and functional diversity, making urgent the maintenance of forests surrounding the plantations as a way to reduce the negative impacts.
Acesso aberto (Open Access)
Chemical analysis of rainfall and throughfall in the Tapajós National Forest, Belterra, Pará, Brazil
(Universidade Federal do Pará, 2015-06) OLIVEIRA JUNIOR, Raimundo Cosme de; KELLER, Michael Meier; RAMOS, Jose Francisco da Fonseca; BELDINI, Troy Patrick; CRILL, Patrick Michael; CARMARGO, Plinio Batista de; HAREN, Joost van
The Tapajós National Forest (FLONA Tapajós) has 600,000 hectares of protected forest, and is situated 50 km south of the city of Santarém, Pará, Brazil, a port city of 250,000 inhabitants that is located at the confluence of the Tapajós and Amazon Rivers. There is a lot of farmland in the region, which offers many opportunities to study changes in land use. Selective wood harvesting is one type of land use that is particularly important to the economy of Santarém. Wet and dry deposition of organic material can be an important source of nutrients for plants, and this is especially true when the soil is poor, which is the case in Santarém-Belterra plateau region, the study area of this research. In this region, the natural atmospheric deposition of nutrients is often enhanced by the burning of biomass, which releases a large part of the above-ground biomass nutrients into the atmosphere. The objectives of this study were: 1 - estimate the total wet deposition via direct precipitation and through the canopy, including dry deposition; 2 - verify potential sources of nutrients found in the total wet deposition and dry deposition; and 3 - investigate the effects of coverage vegetation on nutrient content in precipitation and throughfall. The study was conducted in FLONA Tapajós at km 67 of Santarém- Cuiabá Highway, south of the city of Santarém. The study area consisted of a portion of 100 x 100 m transects divided into 10 x 10 m plots. The area was located next to a meteorological tower 65 m tall that measures various climate parameters such as rainfall, wind speed and direction, solar radiation, temperature and humidity, among others. Direct precipitation (PD) and internal precipitation (IP) collectors consisted of 2 L polyethylene bottles with a 115 mm diameter funnel. Samples were collected weekly from April 2003 to March 2006. The volume of the sample was measured individually for each collector (25 traps for internal precipitation and 4 for direct precipitation). The conclusions that can be drawn from this study are: 1 - the dry season has the highest variation in ion flux; 2 - seasonality has a strong influence on the concentration of basic cations; 3 - dry deposition is one of the most important ways that nutrients are acquired in FLONA Tapajos; 4 - there is a significant inflow of nutrients Cl and Na due to intensive grain farming nearby; 5 - dry deposition is the most important process for the enrichment of water that reaches the forest floor; 6 - principal component analysis facilitates the interpretation and characterization of rainwater and in this study shows the influence of anthropogenic sources such as agriculture, biomass burning, and dust.
Acesso aberto (Open Access)
Conidial fungi associated with leaf litter of red cedar (Cedrela odorata) in Belém, Pará (eastern Brazilian Amazon)
(Instituto Nacional de Pesquisas da Amazônia, 2018-09) SANTOS, Renato Ferreira dos; SOTÃO, Helen Maria Pontes; MONTEIRO, Josiane Santana; GUSMÃO, Luís Fernando Pascholati; GUTIÉRREZ, Antonio Hernández
The aim of this study was to investigate the species of conidial fungi associated with leaf litter of Cedrela odorata (Meliaceae), an endangered red cedar species typical of Amazonian terra-firme forests. Conidial fungi were sampled around C. odorata individuals in three forest areas in the municipality of Belém (Pará State, Brazil). A total of 104 species were identified, with 53 new records for the state of Pará, 46 first records for the Brazilian Amazon, including new records for Brazil (Cordana abramovii), for South America (Acarocybiopsis cubitaensis, Xylocladium claviforme) and for the Americas (Dactylaria biguttulata). A review of species of conidial fungi reported on C. odorata is provided, indicating its distribution in Brazil. For each new record in Brazil, South America and the Americas we present a description, illustrations, geographical distribution and taxonomic comments.
Acesso aberto (Open Access)
Equações alométricas para estimar a biomassa acima do solo em floresta plantada com tachi-branco (Tachigali vulgaris), Dom Eliseu/ Pará.
(Universidade Federal do Pará, 2019-07-24) CERVEIRA, Suzane Serrano; CATTANIO, José Henrique; http://lattes.cnpq.br/1518769773387350
The biomass study in tropical FORESTS has played a major role in relation to the contribution of ecosystems to the global carbon cycle. Many articles suggest planting Tachigali vulgaris (Taxi-White) for carbon capture projects in the Amazon and the generation of carbon credits. However little is known how to estimate the biomass increment and how different spacing interferes with the local microclimate. The present study was conducted at Genesis farm in Dom Eliseu city, Pará State, aimed to determine allometric curves for accumulation of aboveground biomass using destructive methods, and the carbon in the biomass and consequent micrometeorological variations in Taxi-White in spacing 4mx2m, 4mx3m and 4mx4m, with population density ranging from 208 to 403 plants per plot. For the equations used a database of 54 trees of a single species, in which were measured variables total height, diameter at breast height (DBH), each sample tree was felled and split the trunk components, branches, and leaves. The fresh weight of each component was obtained in place, and green samples were collected, weighed and brought to the laboratory in Bethlehem to oven drying to constant weight. 17 models of regression equations were used commonly used in the literature, being chosen equations with a higher coefficient of determination (R²). The stock biomass and shoot carbon were observed in the denser spacing, ie, 4mx4m, focusing mainly on the tree trunk. The distribution of the moisture content of classes was: leaves > branches > trunk. The trunk segment is divided according to their height into steps (BASE, DAP, 25%, 50%, 75% and 100% of the total stem height, DAP had a higher moisture content than the other compartments. The temperature was greater spacing with lower density (4mx4m) and the relative humidity had its highest values for spacing with higher densities (4mx2m). The months of September and October showed higher temperature and lower relative humidity, however, the months of November and December, showed lower temperature and higher relative moisture.
Acesso aberto (Open Access)
How a simple and stereotyped acoustic signal transmits individual information: the song of the White-browed Warbler Basileuterus leucoblepharus
(2004-06) AUBIN, Thierry; MATHEVON, Nicolas; SILVA, Maria Luisa da; VIELLIARD, Jacques Marie Edme; SEBE, Frederic
The White-browed Warbler Basileuterus leucoblepharus, a common bird of the BrazilianAtlantic forest, emits only one distinct song type in the context of territorial defense. Individual or neighbor-stranger recognition may be more difficult when birds share similar songs. In fact, the analysis of songs of different individuals reveals slight differences in the temporal and the frequency domains. Effectively, a careful examination of the signals of different individuals (21) by 5 complementary methods of analysis reveals first, that one or two gaps in frequency occur between two successive notes at different moments of the song, and second, that their temporal and frequency positions are stereotyped for each individual. Playback experiments confirm these findings. By propagation experiments, we show that this individual information can be only transmitted at short range (< 100 m) in the forest. In regard to the size and the repartition of territories, this communication process appears efficient and adaptive.
Acesso aberto (Open Access)
Precipitação efetiva e interceptação em Caxiuanã, na Amazônia Oriental
(Instituto Nacional de Pesquisas da Amazônia, 2008-12) OLIVEIRA, Leidiane Leão de; COSTA, Rafael Ferreira da; SOUSA, Francisco de Assis Salviano de; COSTA, Antonio Carlos Lôla da; BRAGA, Alan Pantoja
The present work was carried out at the Ferreira Penna Scientific Station, in the Caxiuanã National Forest, Melgaço, Pará, Brazil (01º 42" 30"S; 51º 31" 45"W; 60 m a.s.l.). The studied region is an upland forest with closed vegetation and a mean canopy height of 35 m although some trees can be 50 m high. The species density is between 450 and 550 plants per hectare. The aim was to quantify the net precipitation, throughfall, stemflow and rain interception by vegetation, from March to December of 2004. For the throughfall measurements 25 rain gauges were randomly distributed in an one hectare area subdivided in one hundred parcels of 10 x 10 m, while the stemflow was measured on seven trees with a stem diameter at breast height representative of the area. The results showed values of net precipitation of 905.4 mm, throughfall of 885.4 mm, stemflow 20 mm and rain interception of 248 mm,corresponding respectively to 78.5%, 76.8%, 1.7% e 21.5% of the total precipitation above the canopy which was 1,153.4 mm for the study period.
Acesso aberto (Open Access)
Refinamento da representação de raízes no modelo de biosfera SiB2 em área de floresta na Amazônia
(Universidade Federal do Pará, 2008) OLIVEIRA, Livia da Silva; CÂNDIDO, Luiz Antonio; http://lattes.cnpq.br/7705103746743754; CATTANIO, José Henrique; http://lattes.cnpq.br/1518769773387350
The objective of this research was to study the sensitivity of the surface flows and soil hydrology in relation to the representation and distribution of roots in the biosfera model for upland forest in the “Amazônia”. The purpose was to evaluate the impact on the representativeness of the energy surface flows, considering the Amazon region seasonality supported by intensive measures carried through in a biological reserve (Biological Reserve in “Cuieiras” River, near Manaus). Eight simulations were conducted with the model of biosphere SiB2 (Simple Biosphere Model - version 2), where each simulation scenario represented a different scenery of roots distribution in a 4.0 m depth, divided in three layers: 0.5 m , 1.5 m and 2.0 m. The roots were distributed favoring the root’s concentration in the surface layer, after that, the intermediate layer and, finally, a concentration of roots below 2.0 m deep. The simulations were conducted for the period of 2003 to 2006, emphasizing the year of 2005 to evaluate the effect of the roots representation in the energy flows (latent heat - LE and sensitive heat - H) and carbon dioxide flow (F_CO2). From the integrated analysis of simulated flows with observational data, measured in the experimental site, was possible to perceive that a reduction in the rainfall for the year of 2005, although to have been lesser in the central part of the Amazon, led the decline in soil moisture, showing that the forest passed for a considerable period of water stress. The model represented the available energy with values very close to those observed, varying seasonally in agreement with the data measured in 2005. However, LE is overestimated during the rainy season, but it shows together with the CO2 flow, the reduction with soil moisture in the dry season period, while H is overestimated by 20 W.m-2 during all the simulated period. These results show that, apparently, the consideration of surface roots are more appropriate for regions with short dry season, as characterized the study area, and deep roots should promote the modeling of the processes of the surface areas with more pronounced dry season. With the results showing that it has necessity to get more information of soil physical properties, appropriate to the region conditions, so that other refinements are effective in distinguishing the behavior of tropical forests under different regimes of water availability in the soil.
Acesso aberto (Open Access)
Relação entre diâmetro do caule e espessura da casca das árvores amazônicas e sua implicação na resistência ao fogo
(Universidade Federal do Pará, 2024-03-28) GAMA, Valter Thiago Pantoja da; FERREIRA, Joice Nunes; http://lattes.cnpq.br/1679725851734904; https://orcid.org/0000-0002-4008-2341; BARLOW, Bernard Josiah; http://lattes.cnpq.br/8559847571278134
The characteristics of plants are important for understanding their functions and relationships with the environment and the functioning of ecosystems. Tropical forests, such as the Amazon, are important for promoting ecosystem services that are important for maintaining biodiversity and human well-being. However, these forests are facing major threats due to human interference, especially climate change and forest fires. Therefore, given this scenario, research focused on forest resistance to disturbance regimes can help in the monitoring and conservation processes of this type of biome. Therefore, the aim of this study was to evaluate the relationship between stem diameter at breast height (DBH) and bark thickness in tropical Amazonian forests, in order to identify the significance of the relationship between these variables and the possible effects on the degree of forest resistance to fire. The study was carried out using forest inventory data from 21 plots in the Lower Tapajós, in the Eastern Amazon - PA. In order to assess the relationship between DBH and bark thickness, data from 11 botanical families was used in a GLMM (Generalized Linear Mixed Effect Models). The relationship between the variables was significant, with an overall explanatory power of 34% for DBH over thickness, and considering the variation between botanical families, this power increased to 50%. Our results show that of the 11 botanical families studied, only half have trees with bark thick enough to be considered resistant (17-23 mm). In addition, in order to consider trees with or without resistance potential, we analyzed bark thickness at a minimum DBH of 10 cm and the increase in bark thickness as DBH increased. Fabaceae, Lecythidaceae and Burseraceae stood out as being more prone to fire mortality. Therefore, considering the high distribution of individuals belonging to these families in the Amazon and the current scenario of forest degradation, ecological impacts and climate change, this work raises insights into the Amazon's forest vulnerability to burning regimes, and the importance of its conservation for climatic conditions on a local and global scale.
Acesso aberto (Open Access)
The role of Lithodoras dorsalis (Siluriformes: Doradidae) as seed disperser in Eastern Amazon
(Sociedade Brasileira de Inctiologia, 2017) BARBOSA, Thiago Augusto Pedroso; MONTAG, Luciano Fogaça de Assis
Ichthyochory is an important process responsible for the high diversity of plant species in tropical flooded forests. Thus, this study aimed to investigate the role of a catfish species, Lithodoras dorsalis, as seed disperser in the flooded forests at the Amazon River mouth, Brazil. Analyzing the stomach contents of 371 individuals of Lithodoras dorsalis, the Germination Potential (GP%) and Germination Speed Index (GSI) of seeds that were removed intact were investigated. This allowed us to evaluate the germination performance of two important species of plants in Amazonia, Euterpe oleracea (Açaí) and Montrichardia linifera (Aninga), after passage through the digestive tract of this catfish species. Given that digestion by L. dorsalis reduced the germination viability of M. linifera and that seeds were often destroyed during consumption, we suggest that L. dorsalis may have a limited role as seed disperser of M. linifera and instead mostly act as seed predator. However, for the species E. oleracea, L. dorsalis was a potential disperser, since the performance of germination of these seeds was improved after digestion. In addition, the number of seeds consumed was directly proportional to the catfish’s body size, reinforcing the role of doradids as potential seed dispersers in tropical forests.
Acesso aberto (Open Access)
Transformação dos principais usos da floresta no município de Moju, nordeste paraense
(2010-07) MOREIRA, Liliane Freitas; MOTA, Dalva Maria da; MELO, Acácio Tarciso Moreira de
The ideas presented here resulted from a survey in the community of Santa Maria, part of Olho D’Água settlement, in the municipality of Moju, State of Pará, Brazil. The objective of the article is to analyze the transformations lived deeply for a group of agriculturists how much to the use of the forest, more specifically the associates to the attainment of huntings and the accomplishment of country, after the change of the condition of use joint for the private use from the implantation of the nesting in 2002. The study revealed significant reduction in capture of hunt by local farmers given to restricted access to hunting areas which are now privet and also given to higher demand caused by the increasing number of settled families.
Acesso aberto (Open Access)
Uso de caixas-ninho pela fauna de vertebrados em relação às variáveis ambientais em um fragmento de Floresta Amazônica em Altamira-Pa
(Universidade Federal do Pará, 2018-07-27) BENTO, Silnara Carmo; GOMES, Felipe Bittioli Rodrigues; http://lattes.cnpq.br/0924023357753741
The Amazon rainforest is considered one of the largest remnants of tropical rainforest in the world, but the sharp exploitation of natural resources in the Amazon has caused a growing loss of biodiversity. These impacts have worryingly reached the fauna that depends on natural cavities present in alive or dead trees as spots for nesting, sheltering or foraging. To compensate the loss of environmental complexity, the use of nest boxes has been successfully used, especially forests of temperate regions, for diverse groups of vertebrates, from birds to mammals. For the Neotropical region, it is necessary to evaluate the efficiency of this environmental intervention through the experimentation and observation regarding the use of these nest boxes in relation to the environmental variables, being our goal to develop these observations in a fragment of Amazon forest in Pará. The study used 30 wooden nest boxes distributed along a RAPELD research module located in a forest fragment in the Xingu region of Altamira. Eight boxes were installed in transect One and 16 transect the Two, added six boxes along the stream. Four boxes per parcel were installed, two at the beginning and two at the end, one 1.5 m hight and the other with 5 m. in relation to the ground; the boxes installed along the stream were fixed with intercalated height (1,5 and 5 m) distanced 50 m each other. Environmental and spatial variables were measured: opening the canopy edge distance, and an average density of the surrounding DAP trees, distance and altitude stream. The Principal Components Analysis (PCA), were used to correlate the occurrence of bird, amphibians and reptiles species, and used to verify the relationship between the nesting site variables and locations in relation to the sampling sites. Seven boxes were occupied by vertebrates, all then as sheltering. Four were occupied by mammals (Didelphidae and Rodentia), two reptiles (Thecadatilus rapicauda) and one amphibian (Osteocephalus taurinus). Sampling covered the entire study area through the heterogeneous distribution of the artificial cavities, there was slight variation between the variables and the nest boxes (PCA - 39.50% explanation of the axes). There was no significant correlation, but a tendency of use for T. rapicauda to occupy boxes associated with the variables distance of the stream and altitude, and mammals with the variable vegetation cover. Different from other Brazilian studies there was low occupation of nest boxes, and our results were not substantial to determine the use of nest boxes for environmental enrichment in fragmented environmental fragments in the Amazon.