Navegando por Assunto "Floresta Nacional de Caxiuanã - PA"

Agora exibindo 1 - 20 de 56

Acesso aberto (Open Access)
Aspectos ecológicos do cachorro-de-padre Auchenipterichthys longimanus (Siluriformes: Auchenipteridae) em igarapés da Amazônia Oriental, Pará, Brasil
(Universidade Federal do Pará, 2010) FREITAS, Tiago Magalhães da Silva; MONTAG, Luciano Fogaça de Assis; http://lattes.cnpq.br/4936237097107099
The aim of this study was evaluate the ecological aspects related to relative growth, size at first maturity, reproduction, energy investment, sex ratio and diet of the driftwood catfish Auchenipterichthys longimanus (Siluriformes: Auchenipteridae) from the rivers of Caxiuanã National Forest, State of Pará, Brazil. The samplings were carried out bimonthly from July 2008 to July 2009. In this period, 625 specimens of A. longimanus were captured, which 338 were females, 251 males and 36 macroscopically undefined individuals. The results indicated a polyphasic growth pattern for both sexes, and the stanza changing point was about 11.5 cm for males and 12.5 cm for females, values close to the estimated size at first maturity (L50). Through the gonadosomatic index (GSI%) was observed reproductive asynchrony between the sexes, where males had higher values of GSI% in January and the females showed a peak in March. We also emphasize the differences in the energy investment patterns between the sexes and maturity, according to Condition Factor (K). In relation to sex ratio, we observed a higher frequency of females at the reproductive period, suggesting a sexual segregation pattern for reproductive purposes, with the possibility of harems formation or reproductive migration. About the diet, A. longimanus was considered omnivorous, tending to insectivorous. However, in March 2009 the catfish A. longimanus was considered frugivorous due to the high consumption of fuits of Virola surinamensis (Myristicaceae). Because of the high occurrence of allochthonous items, this research highlights the importance of the riparian forest as food source for one of the most abundant fish species in the Caxiuanã region. Since the seeds of V. surinamensis remain intact in the stomach, we evaluate the ecological potential of A. longimanus as a seed disperser, checking the seed feasibility after sowing. Thus, we expect to contribute with the ecological knowledge about A. longimanus, the ecology of the Auchenipteridae family, and also the decision-making concerning politic-environmental questions related to the conservation and management of natural fish populations stocks in one of the largest units of conservation in the State of Pará.
Acesso aberto (Open Access)
Aspectos observacionais e numéricos da interação floresta-atmosfera na Amazônia oriental: fenômenos turbulentos noturnos
(Universidade Federal do Pará, 2008) NOGUEIRA, Daniele Santos; GANDU, Adilson Wagner; http://lattes.cnpq.br/8491359374260645; SÁ, Leonardo Deane de Abreu; http://lattes.cnpq.br/0107976161469463
This study identified two nocturnal turbulent phenomena above Caxiuanã region, in the eastern Amazonia, during its dry season: low level jets (LLJ) and wind gusts, using data from the field campaigns CiMeLA (dry season of 2003) and COBRA-PARÁ (dry season of 2006). Both of them were analyzed observationally, considering aspects such as time of occurrence, intensity, height and duration, as well as their nocturnal evolution. It was verified that most of the LLJ events were accompanied by a drop in equivalent potential temperature. It was also found that the wind gusts had an important influence over the forest-atmosphere exchanges. The genesis of these phenomena was also investigated. It was noted, using the mesoscale model BRAMS, that the origin of the jets is possibly associated to the sea breeze and the intensification of the northeasterly winds. These results were based on sensibility tests, which included the removal of the rivers, the ocean-continent interface, the effects of downdrafts and the deforestation of the region. It was observed that the origin of the wind gusts is associated to the existence of Caxiuanã bay, which resembles a lake, and to the local convective activity. Furthermore, it was found that both phenomena did not exist simultaneously, except for one single night. This can be explained by a shear-sheltering effect that impedes that propagation of the turbulence downward, to the surface. This effect is generated by the presence of strong LLJs. This research reflects the importance and complexity of the atmospheric phenomena near the coast of Pará.
Acesso aberto (Open Access)
Aspectos reprodutivos e alimentares da piranha Serrasalmus gouldingi fink & machado-allison, 1992 (Characiformes: Serrasalmidae) em rios afogados da Amazônia Oriental
(Universidade Federal do Pará, 2012) PRUDENTE, Bruno da Silveira; MONTAG, Luciano Fogaça de Assis; http://lattes.cnpq.br/4936237097107099
The present work aimed to evaluate the reproductive biology, condition factor and feeding ecology of Serrasalmus gouldingi in relation to fluviometric variations of lower Anapu River, in “drowned” rivers of Caxiuanã National Forest, Eastern Amazonia, Pará, Brazil. 275 specimens were bimonthly collected during July 2010 to May 2011 and their total length, total weight, gonad and stomach weight were measured. The gonads were analysed histologically to verify the sex and maturation degree, while the stomachs were evaluated through the identification of the consumed items. The sexual proportion did not differ from 1:1considering the studied period as a whole, however the females were more frequent during the transitional periods of drawdown and filing. The species spawning was “parcelada”, showing two peeks of reproductive activity during the periods which preceded the increase in the local fluviometry. The L50 was estimated in 12.24cm for males and in 16.13cm for females. The species growth was positively alometric, showing a gain of weight in relation to length, and the condition factor, when analysed along the entire sample period, decreased mostly during the spawning. The diet of S. gouldingi was composed of 32 items, grouped in 10 categories. The composition indicated an omnivorous diet with a strong tendency to piscivory, once fish fragments were the most predominant item, followed by fruits and seeds and allochthonus arthropods. The distinct hidrological periods were significantly different in relation to diet composition, although no significant difference was detected among sex and maturation degree. Males and females showed the same variation pattern of repletion index, with a more intense feeding during the increase of the river´s level, while it was less intense during the transitional periods (drawdown and filing). The species also showed some variation in their breadth niche, with lower values during the wet period, attributed to the almost exclusive consumption of fruits and seeds.
Acesso aberto (Open Access)
Avaliação de características dos regimes de umidade na flona de Caxiuanã-PA durante o experimento COBRA-PARÁ
(2010-03) TANAKA, Ludmila Monteiro da Silva; SÁ, Leonardo Deane de Abreu; MOTA, Maria Aurora Santos da
We investigate the validity of a method of humidity regimes classification, based on different "states" characterization of the Tropical Atmospheric Boundary Layer (TABL), above a forest area, according to the methodology proposed by Mahrt (1991). To perform this investigation we used radiosonde information and micrometeorological tower data collected during the drier season of the region, during the experiment "COBRA-PARÁ" (carried out from 30/10 to 15/11, 2006). The analysis of moisture regimes is based on the "phase space" data representation, where the Bowen ratio (β) is plotted against the -h/L parameter (where h is the height of the turbulent mixing layer and L is the Obukhov length scale). According to the location of the data value in this "phase space" it was possible to identify the following classes: Class I - dry air and unstable conditions, Class II - dry wind, Class III - wet wind, Class IV - wet air and unstable conditions, Class V - occurrence of water condensation on the surface, Class VI - stable conditions predominance and Class VII - dew formation generated by nocturnal radiative losses with surface cooling. Among the mentioned classes, the III, IV and VI were the most frequently observed at Caxiuanã.
Acesso aberto (Open Access)
Biologia reprodutiva e hábito alimentar de Dendrophryniscus minutus (Melin, 1941)(Amphibia : Bufonidae) na Floresta Nacional de Caxiuanã, Pará
(Universidade Federal do Pará, 2003-06) TRAVASSOS, Alessandra Elisa Melo; GALATTI, Ulisses; http://lattes.cnpq.br/1040132527458660
This study examined reproductive characteristics, nutritional status and feeding habits in the litter anuran Dendrophryniscus minutus through individuals collected in the Estação Cientifica Ferreira Pena, Caxiuanã National Forest from April 1997 to April 1998. In a sample of 166 specimens were measured snout - vent length (SVL), mass of fat bodies, diameter, mass and number of ova in females and testis volume in males. The feeding habit in this species was also determined through analyses of stomach contents. Population structure showed a pattern with most adult individuals, including gravid females, in the rainy months, and juvenile recruitment in the beginning of the dry season. Similarly, the diameter and mass ova in the mar', used as indexes of gonadal development stage, were greater in the rainy season. Among males, the biggest testis volume also appeared in february and april, but there was no evident pattern of correlation to rainfall. Food consumption also did not show any pattern in variation along months and it was not correlated to fat mass. Fat bodies measurements were positively correlated to ova development in females indicating that fat accumulation and gonadal development may occur simultaneously. The diet in specie was composed for ants, termites and mites, terrestrial invertebrates in a great number in a litter in the studied area.
Acesso aberto (Open Access)
Characterization and distribution of pyrogenic carbon in a fraction of archaeological black earth from Caxiuanã
(2015-08) MORAES, Milena Carvalho de; LEMOS, Vanda Porpino; MORAES, Dorsan dos Santos; MORAES, Cláudio Nery Lamarão
This study aims to determine the atomic ratio of O/C in an archaeological black earth (ABE) profile of the Ilha de Terra site, a region of Caxiuanã in the Pará State, Brazil, to determine the types of pyrogenic carbon (PyC) particles and to infer the source of biomass and burning temperature necessary to produce the PyC. The O/C ratios were monitored using scanning electron microscopy combined with energy dispersive spectroscopy (SEM/EDS). The results indicated atomic ratios for clay, silt and fine sand fractions that were between those registered for the PyC particles types: condensed combustion (CC) (0.09, 0.1, 0.13), charcoal (0.32, 0.31, 0.34) and char (0.43, 0.45, 0.52). CC is the predominant type of particle found because of the high firing temperature (> 350 °C), which is consistent with the probable biomass sources of wood, cellulose and lignin.
Acesso aberto (Open Access)
Cientistas, visitantes e guias nativos na construção das representações de ciência e paisagem na Floresta Nacional de Caxiuanã
(Universidade Federal do Pará, 2007) BEZERRA, Maria das Graças Ferraz; ANTONAZ, Diana; http://lattes.cnpq.br/7547028254641362
Study analysis scientific knowledge production process in a traditional knowledge setting at Caxiuanã National Forest, in Melgaço, Pará, Amazon, Brazil, where the Goeldi Museum maintains a scientific basis open for Brazilian and International researchers. The focus is on the relationship between scientists and native field guides considering both the environment where they work and the given academic system.
Acesso aberto (Open Access)
Comportamento alimentar e dispersão de sementes por guaribas (Alouatta belzebul) na Estação Científica Ferreira Penna (Caxiuanã / Melgaço / Pará)
(Universidade Federal do Pará, 1999-04-13) SOUZA, Luciane Lopes de; FERRARI, Stephen Francis; http://lattes.cnpq.br/3447608036151352
The behaviour of two free-ranging groups of red-handed howler monkeys (Alouatta belzebul) was monitored at the Ferreira Penna Research Station (Pará) over' a thirteen-month period in 1997/98, in order to record their ecological characteristics, especially their diet and seed dispersal. Quantitative behavioural data were obtained using instantaneous scan sampling. Invariably, the howler monkeys were relatively inactive, dedicating more than half their activity time to resting, and much smaller proportions to locomotion, feeding and social behaviour. Use of the home range was strongly influenced by the distribution of food patches, in particular fruiting trees. The diet was basically folivorous-frugivorous, although fruit was the item consumed most frequently (54.1 % of feeding records for the principal group, denominated "L") in the "winter" months (November-April), whereas leaves were consumed far more frequently (84.5 %, group L) in the "summer" (May-August). Seeds took 22:49±6:12 h, on average, to pass through the digestive tract, and ingested seeds were dispersed a mean distance of 172,0±113,8 m, although this distance was significantly greater in the winter. Germination rates recorded in tests in both field and laboratory were inconclusive on the effects of ingestion on viability. The germination rate of ingested seeds was significantly greater than the control (uningested) in only a few cases, such as that of Ficus guianensis, the principal source of fruit. Even so, ingestion did not have a marked negative effect on viability in any case. Overall, the present study reforces the view of A. belzebul as a typical howler monkey, ecologically, albeit relatively frugivorous, and playing a important role as a seed disperser in the Amazon Forest.
Acesso aberto (Open Access)
Composição e diversidade de espécies da anurofauna da Estação Científica Ferreira Penna, Floresta Nacional de Caxiuanã, Pará, Brasil
(Universidade Federal do Pará, 1999-08-30) BERNARDI, José Antônio Renan; OREN, David Conway; http://lattes.cnpq.br/5451507856491990
This study compares the composition of the anurofauna of the four principal habitats (terra firme forest, capoeira, igapô and aquatic vegetation) in the areas of two black water streams (igarapé Arauá and Laranjal), at the "Ferreira Penna Scientific Station" (Estação Científica Ferreira Penna (ECFPn)), located in the "Caxiuanã National Forest (FLONA de Caxiuanã)", Pará, Brazil. The samples of the areas were conduct using transects measuring 850 m in length and 10 m in width. Both areas were studied in the four periods of the year and related to annual rainfall seasonality (period of transition rainy/dry season, dry season, transition dry/rainy season, and rainy season). Shannon-Weiner índex of diversity and Jaccard index of similarity were used to compare the two areas and the habitats. Samples of anurans totalled 924 individuais belonging to 29 species distributed in 15 genera and 5 families. Hylidae was the most abundant, followed by Leptodactylidae, Dendrobatidae, Bufinidae and Pipidae. Terra firme forest showed the highest diversity. The number of species recorded was highest in the rainy season. This study and those of Ávila-Pires and Hoogmoed (1997) indicate a total of 41 species of frogs for this region, a quite high number for eastern Amazonia, reinforcing the hypothesis that the low diversity of the species of frogs normally related to this region is at least partially a result of the low number of herpetological inventories carried out up to now.
Acesso aberto (Open Access)
Crianças ribeirinhas e quilombolas da Amazônia: crescimento, determinantes sociais de saúde e políticas públicas
(Universidade Federal do Pará, 2016-09-29) FILGUEIRAS, Ligia Amaral; SILVA, Hilton Pereira da; http://lattes.cnpq.br/3917171307194821
The Amazon represents over half of the tropical forests in the world and has the highest biodiversity in the world, but continues to suffer serious environmental problems due to the illegal exploitation of its resources. Human populations living in these areas are indigenous and non-indigenous, largely rural, with intense miscegenation between white settlers, the indigenous native population and Africans who came as slaves. They are small producers who depend on and deeply know the nature and its cycles and use relatively simple technology, little impact on the environment. These populations living in rural areas are considered made vulnerable, especially children. This study aimed to assess the health situation of children from three population groups of the Amazon residents National Forest Caxiuanã (PA), the Sustainable Development Reserve Mamirauá (AM) and seven Quilombo communities (Africa / Laranjituba, St. Anthony , hoses, Spring, Oriximiná, Trumpets and Abacatal - PA). 990 children were analyzed 0 to 9 years of age compared to WHO criteria from 2008 to 2015. It was found that children Caxiuanã are in deficit height / age (26.15%) and children Mamirauá (17.9%), while among the Maroons the most serious situation was in the Spring community (35.72%). The difference between them was significant (p = 0.018) and the Tukey test indicates that children Caxiuanã are worse off with regard to weight / age. In general, all communities lack environmental sanitation, running water, have substandard housing, including without bathroom or internal health, which influences the high levels of intestinal parasites, skin infections and other diseases. Access to health services is often difficult due to the distances between homes and health centers, as in most cases the transport is poor. The Amazon region is vast and difficult to manage, but if there is no serious improvements in public policies in all sectors, children in rural areas still remain distant from international growth parameters in the 21st century Therefore, it is necessary that best public health programs are developed to the Amazon region, which are reflected in better quality growth and health.
Acesso aberto (Open Access)
Distribuição espacial de anuros e lagartos ao longo de gradientes ambientais em uma floresta de terra firme na Amazônia oriental, Pará, Brasil
(Universidade Federal do Pará, 2008-08-18) GOMES, Jerriane Oliveira; ÁVILA-PIRES, Teresa Cristina Sauer de; http://lattes.cnpq.br/1339618330655263
This study aims to investigate the relationship between anuran and lizard communities, as well as of some individual species, with leaf litter depth, total basal area of trees, understorey vegetation density, and canopy cover. Sampling occurred between August and November 2007, in a 25 km² grid implanted by the ‘Programa de Pesquisa em Biodiversidade’ (Biodiversity Research Program - PPBIO) / Amazônia, located in the Floresta Nacional de Caxiuanã, Pará, Brazil. Two sampling methods were used: active search and pitfall traps with drift fences. A total of 892 lizard and anuran individuals, of 27 species (15 anuran and 12 lizard species), were recorded. Twelve anuran species (101 individuals) and 12 lizard species (171 individuals) were registered through active search, whereas 11 anuran species (327 individuals) and 15 lizard species (293 individuals) were captured by pitfall traps. No significant relationship was found between distribution of anuran and lizard communities with environmental predictors, indicating that these species occur throughout all studied environmental gradients. Only the lizards Coleodactylus amazonicus and Ptychoglossus brevifrontalis were significantly associated with understorey vegetation density and leaf litter depth, respectively. This study is expected to contribute to the improvement of the research design for the herpetofauna within PPBIO.
Acesso aberto (Open Access)
Diversidade e composição de formigas Ponerines (Hymenoptera, Formicidae, Ponerinae) de Serapilheira na Estação Científica Ferreira Penna, Caxiuanã, Melgaço, Pará, Brasil
(Universidade Federal do Pará, 2009-05-21) BASTOS, Alexandro Herbert dos Santos; HARADA, Ana Yoshi; http://lattes.cnpq.br/4410204692155098
The ponerines, after myrmicines, are the most conspicuous, rich and abundant ground-dwelling ants from tropical rain forests. In this ecosystem the ponerines are ecologically important, since they prey many kinds of invertebrates and nest among leaf litter and rotten logs. In this work the range of leaf litter Ponerinae ants was studied, as well their abundance, richness, diversity, and species composition. In addition, how the litter quantity affect the ponerines range was analyzed. This study was carried out in six primary Amazonian forest areas of 1 Km² (Area I, II, III, IV, V, and VI) at Ferreira Penna Scientific Station (ECFPn), Caxiuanã, Melgaço, Pará state, Brazil. The material was collected at April and October of 2003, and January of 2004, following the Ants Monitoring Protocol of TEAM Iniciative/Caxiuanã Project for the study of leaf litter ants. In each sampled site four transects lines of 100 m (sample units) with 10 samplings points were established. At each sampling point of 1 m², the leaf litter samples were sifted and then placed in mini-Winkler sacks. A total of 4,031 specimens were collected, belonging to three tribes, eight genera, and 60 species of Ponerinae in 470 records. In average 6.52 species were collected per sample. The total richness was estimated in 81 species using first order Jackkinife method. Hypoponera was the most abundant and rich genus, with 22 species in 268 records. The genus Hypoponera plus Pachycondyla showed a strong numerical dominance, with more than 70% of collected species. The Area V was the most diverse (H=3.30), with the highest species richness (38) and abundance (121 records), as well as with the largest amount of leaf litter (ANOVA; p<0,05 between Area V and the other sites). The quantity of leaf litter affected positively the ponerines ants species abundance and richness, and also influenced the species composition. The most common species were: Hypoponera sp#1, Hypoponera sp#2, Hypoponera sp#6, Hypoponera sp#7, Odontomachus scalptus and Pachycondyla constricta. These few species (10%) yielded more than half of total abundance. In short, the ponerines were widely spread in the leaf litter of ECFPn primary forests, being numerically affected by leaf litter volume. The sites showed differences in species diversity, abundance and richness. Furthermore, the species composition of ponerines ants at nearby samples often presented low similarity once high number of species was rare. Thus, the leaf litter availability of Amazonian forest is a key role on species distribution, even at small scales.
Acesso aberto (Open Access)
Diversidade, distribuição e estrutura da comunidade de peixes na Estação Científica Ferreira Pena: Amazônia Oriental
(Universidade Federal do Pará, 2001-11-20) MONTAG, Luciano Fogaça de Assis; BARTHEM, Ronaldo Borges; http://lattes.cnpq.br/4192105831997326
The conservation of the biodiversity in aquatic ecosystems is one of the most important and difficult challenges in the current world. According to available information, the biodiversity of aquatic ecosystems is poorly understood in comparison with tropical terrestrial ecosystems. Thus, systematic and taxonomic analyses, the understanding of phylogenetic, biogeographical and ecological relationships represent items that need to be investigated. The first question addressed is the characterization of the ecosystem. We observed that the environmental features, mainly wideness and depth, ranges spatially along the rivers and possess the inferior zone with strong characteristics of river—lake transitional areas. The following question was to estimates fishes richness of in the Ferreira Penna Scientific Station. In order to answer this question, we used protocol techniques and obtained 130 species, of these 39 were separated by morphospecies. This fact indicates that approximately 30% of the fauna might be new or there is no available bibliography for identification. The species collected in the inventory are considered to represent a reasonable set of the ichythyofauna of the region. Lastly, we aimed to characterize fish communities and expose the patterns of distribution of species concerning the investigated habitats. As a result, we observed that the com position of species in the communities followed the substitution and addition pattern. The greatest diversity of species was observed for the final zones of the rivers. The increase in the water volume and area in some habitats of the rivers makes possible their exploitation by a larger number of individuals or new species.
Acesso aberto (Open Access)
Ecologia de culicídeos vetores de febre amarela silvestre em relação ao microclima na Floresta Nacional de Caxiuanã-Melgaço-PA
(Universidade Federal do Pará, 2007) PINTO, Claudeth de Souza; MASCARENHAS, Bento Melo; http://lattes.cnpq.br/3279744837272788; CONFALONIERI, Ulisses Eugênio Cavalcante; http://lattes.cnpq.br/0960107425984526
The species vectors of yellow fever are distributed, in the Americas, in the genera Haemagogus and Sabethes. The culicidae have their blood-sucking activities influenced both by endogenous and exogenous factors, such as the responses to microclimatic factors. The micoclimate and the stratification of the mosquito hosts are the main determinants for the occupation of ecological niches by culicids in the tropical forests. This study was developed in the micrometeorological tower of the Caxiuanã National Forest, in the municipality of Melgaço, State of Pará, Brazil. The aims were to analyse the vertical distribution of the species vectors of yellow fever in relation to microclimate in the dense upland forest, from July 2005 to April 2006, at ground level and in platforms at 8m, 16m and 30 meters. Collections were made for 12-hour periods, both at night and during the day, with the use of human attractors. Temperature and humidity records were made at all heights where the collections were made and the precipitation was measured at the top of the tower. A total of 25,498 specimens of culicids were collected, among which 1028 were from the genus Haemagogus and 502 from Sabethes, captured during daytime. The species of Sabethes and Haemagogus janthinomys were found mostly at the canopy level, especially at the heights of 16 and 30 meters, while Haemagogus leucocelaenus was more frequent in the ground. The rainiest months were associated to the greatest number of specimens of the different species but this was not statistically significant. However, there was a significant relationship between temperature, relative humidity and the number of yellow fever vectors collected.
Acesso aberto (Open Access)
Efeito da alteração do hábitat sobre assembleias de peixes em igarapés afogados da Amazônia oriental
(Universidade Federal do Pará, 2014-02-26) SOUSA, Híngara Leão; FERREIRA, Cristiane de Paula; http://lattes.cnpq.br/7804816854015308; MONTAG, Luciano Fogaça de Assis; http://lattes.cnpq.br/4936237097107099
The natural aquatic ecosystems are complex systems that are exposed to a variety of disturbances. In the Amazon region, for instance, land use and occupation have altered the physical structure of aquatic environments, especially regarding the small streams, influencing their communit structure and composition. This has led to research development and evaluation programs to see how the changes that are occurring in these environments affect biotic communities, through habitat characteristics that are more sensitive to disturbance. Thus, this study aimed to describe and measure physical attributes of drowned out streams and evaluate how fish assemblages respond to different levels of streams physical integrity. Our hypothesis is that structurally intact environments endure a more diverse ichthyofauna than altered environments, since their decreased environmental complexity limits the potential ecosystem, because they presented a decrease in environmental complexity. The study was conducted in 34 streams, 17 located within the territory of Caxiuanã National Forest, and 17 in its surroundings, located close to Portel and Melgaço cities (PA). The process of urbanization is expanding in the region, reaching areas of forests and streams that are still preserved. There is also an intense logging, because the area is included in the main timber pole of the estuary in the state of Pará. The physical habitat was evaluated according to a standardized protocol of stream environmental assessment. The samplings were conducted with hand nets passed along 150 meter long reaches during six hours (divided among segments and collectors). Although a set of metrics which responded to the local impact gradient has been detected these were not sufficient to reduce or increase the number of species across different levels of preservation, maintaining substantially constant the wealth and abundance for all three groups (altered, intermediate and preserved). However, the difference was significant for the composition, with eleven exclusive exclusive species of altered habitats and eight preserved environments. The degradation of the physical environment, even at smaller scales favors the occurrence and abundance of most tolerant species and phenotypic plasticity, in addition to the population increase of opportunistic species. Different effects can be exerted on the groups of species that make up a community, since they have different biological and ecological attributes that include your answers to the same ecological variables. Therefore, the possible deconstruction of community groups of species (taxonomic, functional, etc.) may show different responses to the changes of habitat, being a promising strategy for linking environmental standards of richness characteristics displayed by these communities. Assessment of biotic integrity is also an alternative to identify effects of habitat alteration on species, especially considering the region’s peculiarity and the lack of information about the local ichthyofauna.
Acesso aberto (Open Access)
Efeito da topografia e da precipitação na florística e na produção de liteira em Caxiuanã, Pará
(2015-12) FERREIRA, Laura Suéllen Lisboa; CATTANIO, José Henrique; JARDIM, Mário Augusto Gonçalves
The objective of this work was to study the effect of topography and rainfall in the structure of trees and litter production in a tropical rain forest in the National Forest of Caxiuanã. Were delimited three tranches of 1.000 m2 in each topographic levels (lowland, intermediate and plateau) and identified all individuals and collection of litter. For the three levels was recorded a total of 124 species belonging to 33 botanical families. The three families with higher importance value index for topographies of lowland and intermediate were Sapotaceae, Lecythidaceae and Chrysobalanaceae and for plateau were Lecythidaceae, Sapotaceae and Chrysobalanaceae. The species Lecythis idatimon Aubl., Rinoria guianensis Aubl. e Eschweilera coriacea (DC.) S.A. Mori. showed the greatest importance value indices for the three topographies. The seasonality affects significantly the litter production, showing the highest values at the end of rainy season and early dry season. The environmental stimulus for the fall of the leaves is mainly due to decrease in relative humidity, justified by the need of the plants to increase photosynthetic efficiency. The difference in population structure show strategies for flower production, and consequently the dispersion of fruits and seeds.
Acesso aberto (Open Access)
O efeito da topografia e microclima na florística e estrutura de árvores e na produção de liteira em uma floresta ombrófila densa na Amazônia Oriental
(Universidade Federal do Pará, 2012) FERREIRA, Laura Suéllen Lisboa; JARDIM, Mário Augusto Gonçalves; http://lattes.cnpq.br/9596100367613471; CATTANIO, José Henrique; http://lattes.cnpq.br/1518769773387350
The object this study was to study the effect of topography and microclimate (temperature and precipitation) in the floristic and structure of trees and litter production in a tropical rain forest in the National Forest Caxiuanã. In the grade of 25 km2PPBio, three areas were chosen (A, B and C) where plots were established 10 x 100 m, following the same topographic profile (lowland, intermediate and planteau). These plots, we identified all trees with DBH ≥ 10 cm for the realization of phytossociologic, taking into account the parameters of absolute and relative density, frequency and dominance, thus calculating the index value of importance (IVI). Micrometeorological temperature data were obtained from connected data logger Hobo Pro v2 and precipitation data were collected by the automatic station of IBAMA. We found 124 species in 33 plant families. The richest families in number of species were Sapotaceae (17), Chrysobalanaceae (10), Lecythidaceae (10) and Caesalpiniaceae (8). The most abundant families in number of individuals were Sapotaceae (65), Chrysobalanaceae (52) and Caesalpiniaceae (40). The area showed little floristic diversity evidenced by the low Shannon Diversity Index (H’= 3.16) and high uniformity in the proportions individuals/species within the plant community, given the degree of evenness of Pileou (J’= 0,94). There were no significant differences in richness and diversity of trees in relation to the plateus, intermediate ans lowland, as well as the density of species and basal area individuals. No there was a clear separation in the composition of tree species (DBH ≥ 10 cm) between the plots sampled in the plateau topographic condition, intermediate and lowland. The family with the higest IVI was Sapotaceae for the topography of lowland and intermediate, and Lecythidaceae for the plateau and species with higher IVI for three topographies were Lecythis idatiomon, Rinoria guianensis and Eschweilera coriacea. The average production of total litter in the nine plots was 758.59 kg ha-1. There was no significant difference in the production of litter in relation to topography and medium temperature and maximum temperature, but in relation to rainfall and minimum temperature there was differences. The leaf fraction (73,55%) was the most representative in the composition of litter, followed by branches (24,98%), fruits (3,88%) and flowers (3,85%). The flower production and fruits showed no significant relationship with the topography. No relationship was found in flower production with rainfall and temperature, but the fruits production showed significant differences with precipitacion and maximum temperature and minimum. The topography does not influence the floristic and structure of trees and litter production in the nine studied plots, but the variation in precipitation and temperature had a strong influence on litter production total and fruit production.
Acesso aberto (Open Access)
Efeitos do espaço e do ambiente sobre assembleias de peixes de igarapés da Amazônia oriental
(Universidade Federal do Pará, 2012) BENONE, Naraiana Loureiro; MONTAG, Luciano Fogaça de Assis; http://lattes.cnpq.br/4936237097107099
The amazon streams have harsh environmental characteristics for several fish species due to their oligotrophic conditions. In spite of that, these watercourses possess a rich and diversified ichthyofauna, resulting from the various microhabitats found in streams. In ria lake systems, the rivers and streams suffer a natural impoundment, which provokes a lowering on current velocity values. This could homogenize the environment, since current velocity affects many of the streams features. Thereby, distance between streams could have its importance emphasized as a structural factor of stream fish assemblages. This study aimed to analyze the influence of space and environment on the structure of fish assemblages in drowned streams of Caxiuanã, in Eastern Amazon. The fishes were caught during the period of drought of 2010, including 34 transects of drowned streams. Eight abiotic factors were measured to test the effect of the environment. To analyze the effect of the space, space filters were calculated based on the geographical coordinates, as well as the distance among the streams following the watercourse. The analyses showed that the environment was the only factor to influence the beta diversity, refuting the hypothesis of the space as a structuring factor and reinforcing the paper of the ecological niche in the distribution of species. Nevertheless, the abiotic factors explained a low percentage of the variation in the fish composition, what shows that other variables can affect these assemblages.
Acesso aberto (Open Access)
Efluxo de CO₂ do solo e biomassa de raízes finas ao longo de um gradiente topográfico na Floresta de Caxiuanã-PA
(Universidade Federal do Pará, 2013-05-07) CASTRO, Sirlene de Lima; CATTANIO, José Henrique; http://lattes.cnpq.br/1518769773387350
The objective of this research was to understand the role of small topographic elevations in the soil carbon dioxide (CO2) efflux comparing different seasonal period in the National Forest of Caxiuanã, oriental Amazon. Were selected two transects with about 17m topographic gradient, the first initiated near the border of a permanent stream and the second standing near an intermittent stream, denominate in this work as Transect1 and Transect2, respectively. In each transect were selected four locations for the collection and measurement of data called lowland, middle lowland, middle plateau and plateau. At these sites were conducted CO2 efflux and soil temperature analysis, and soil samples for organic carbon analysis and fine root (<2 mm) biomass studies at different depth intervals. It was observed a significant difference in the soil organic carbon concentration compared in the soil surface layer (0-10 cm) in lowland topography, where the transect that begins in the board of the intermittent stream had the significantly higher organic carbon content. It was also observed a soil organic carbon reduction with depth, but there were no differences in organic carbon content with topographic variation. Bringing together both transects, the results related to superficial fine root biomass, it was found mean values of 382.47 ± 25.46 g m-2 for the dry months and 298.24 ± 23.50 g m-2 for the rainy months. In general there was a reduction in fine root biomass by increasing the soil depth, and in the surface layer (0-30 cm) is concentrated to greater root biomass with more than 80% of total root biomass for both transects. There were significant differences in root biomass among and within transects. For the same time, it was founded higher CO2 efflux in the lowland topography compared to the plateau. Seasonal variation also has effect on soil CO2 efflux, with the month of August (transitional month) having the highest CO2 effluxes and March (rainy month) the lowest CO2 efflux, independent of topographic position.
Acesso aberto (Open Access)
Estresse oxidativo de aves em clareiras naturais e sub-bosque na região Amazônica
(Universidade Federal do Pará, 2013) GOMES, Andreza de Lourdes Souza; SILVA, José Maria Cardoso da; http://lattes.cnpq.br/6929517840401044
Background: (Oxidative stress of birds in natural gaps and understory sites in the Amazon region). Studies that provide information about the distribution of birds in different phases of forest mosaic are essential for understanding the maintenance of biodiversity, since natural gaps play a central role on the structure and dynamics of tropical forest. Objectives: (a) to determine and compare the abundance and richness of frugivorous birds between the natural gap and understory habitats; (b) verify and associate the abundance of frugivorous birds with the availability of fruits in both areas; (c) to investigate the echophysiological interactions between the oxidative stress and the distribution of specimens of Dixiphia pipra and Willisornis poecilinotus, to determine which factors account for the variance of biomarkers of oxidative stress in these species. Methods: This study was carried out from November 2010 to October 2011 in terra firme forest sites at the National Forest of Caxiuanã, Melgaço, Pará, Brazil. Two different understory forest habitats were selected for sampling on the basis of physiognomies: natural tree fall gap and undisturbed forest. Twelve (12) sites were selected (6 natural gaps and 6 undisturbed continuous forests). In each site, groups of 10 mist nets were set at ground level which remained open from 6:00am to 2:00pm for two consecutive days, totaling six days each month. This procedure lasted for 12 months and the sampling effort totaled 23,040 mist net hours. All specimens captured were identified, marked with metal rings and kept in cotton bags. We collected blood, feces and regurgitation samples to determine the biomarkers of oxidative stress and the composition of the diet. The relationship between thiobarbituric acid reactive substances and the total antioxidant capacity was used as an index of oxidative stress. The vegetation structure was determined based on transects along the mist nets; the plants bearing fruits were identified and the total antioxidant capacity was determined in each plant. Results: During the period of the study 347 specimens of 21 species were sampled. The assemblage of frugivorous birds in natural gap is distinct from that of undisturbed forest sites. The species responsible for dissimilarity were Dixiphia pipra, Pipra rubrocapilla and Turdus albicollis. The richness of birds was similar in both sites, but the availability of fruits and the total capture index were higher in natural gaps. The primary frugivores (those whose feces or regurgitation always showed fruit pulp or seeds) occurred mainly in natural gaps, where the most abundant species was Dixiphia pipra. In addition, Pipra rubrocapilla was the most abundant species in undisturbed sites. Thirty-six (36) species of plants bearing fruits were recorded, and the abundance of frugivorous birds was significantly correlated with the number of plants bearing fruits in natural gaps, where the most common species of plants were: Psychotria colorata and Psychotria iodotricha. On the other hand, Faramea anisocalyx and Virola surinamensis were the most common species in undisturbed sites. The variation of biomarkers of oxidative stress in specimens presenting lek behavior varied with gender and to the site of sampling. In natural gaps, the adult males of Dixiphia pipra showed higher levels of oxidative stress. The high metabolic rate resulting of flight effort to avoid predators, courtship behavior to the female and territory defense, can increase the production of pro-oxidant compounds. However, the ingestion of fruits with high content of antioxidant compounds by male can minimize the deleterious effects of oxidative stress. The variance of oxidative stress of species that do not have organization in leks was associated only with the site of sampling. The specimens sampling in natural gaps showed higher levels of oxidative stress. This can be due to the increase in metabolic rate to avoid predators as well as new flight strategies for foraging.