Navegando por Assunto "Floresta de terra-firme"

Agora exibindo 1 - 8 de 8

Acesso aberto (Open Access)
Caracterização e dinâmica espacial da caça de primatas em comunidades ribeirinhas da Amazônia Central
(Universidade Federal do Pará, 2015) PEREIRA, Priscila Maria; VALSECCHI, João; http://lattes.cnpq.br/8353254163114394; QUEIROZ, Helder Lima de; http://lattes.cnpq.br/3131281054700225
Acesso aberto (Open Access)
Crescimento de espécies arbóreas em uma floresta natural de terra firme após a colheita de madeira e tratamentos silviculturais, no município de Paragominas, Pará, Brasil
(Universidade Federal de Santa Maria, 2015-12) SOUZA, Deivison Venício; CARVALHO, João Olegário Pereira de; MENDES, Fernanda da Silva; MELO, Lia de Oliveira; SILVA, José Natalino Macedo; JARDIM, Fernando Cristóvam da Silva
This paper deals with the effects of silvicultural treatments on growth rates of a terra firme natural forest after reduced impact logging (RIL). The study was carried out in the Rio Capim Forest Management Unit, which belongs to Cikel Brasil Verde Madeiras Ltda., located in the municipality of Paragominas, PA. The experimental area comprised 500 ha, where five treatments (100 ha each) each with four replications (25 ha each) were established. The replications were randomly distributed in the 500 ha sample area. The following treatments were applied: T1 - RIL + classical liberation thinning (girdling of competing trees) and climber cutting; T2 - RIL + modified liberation thinning (girdling of competing trees) and climber cutting; T3 - RIL + climber cutting; T6 - only RIL; T7 - unlogged forest (control). In the four years of monitoring forest, after logging and silvicultural treatments, T2 and T3 had the highest diameter growth rates. But the four-year period is not enough to suggest the best treatment, based on diameter growth rate, in response to girdling trees and climber cutting. At species level, growth rate varied between treatments and within treatments. In general, the lower diameter growth rates were observed in the unlogged forest.
Acesso aberto (Open Access)
Dinâmica da estrutura da vegetação do sub-bosque sob influência da exploração em uma floresta de terra firme no município de Moju - PA
(Universidade Federal de Santa Maria, 2013-06) MENDES, Fernanda da Silva; JARDIM, Fernando Cristóvam da Silva; CARVALHO, João Olegário Pereira de; SOUZA, Deivison Venício; ARAÚJO, Clívia Bezerra; LEAL, Eduardo da Silva; OLIVEIRA, Mariana Gomes de
The structure dynamics of an understorey vegetation influenced by gaps caused by reduced impact logging was analyzed during 12 years in a terra firme rain forest in the municipality of Moju, Pará state, eastern Brazilian Amazon forest. Angiosperm individuals from 10 cm height up to 5 cm DBH were surveyed in a 468 m² sample area in six occasions (1998, 1999, 2000, 2001, 2007 and 2010), they were analyzed considering their life-forms (trees, shrub, lianas, herbs and palms), abundance, frequency, size classes (CT1 = 10 cm ≤HT <50 cm; CT2 = 50 cm ≤HT ≤ 130 cm; CT3 = 130 cm
Acesso aberto (Open Access)
Estudo comparativo de comunidades de briófitas sujeitas a diferentes graus de inundação no município de São Domingos do Capim, PA, Brasil
(Universidade Federal do Pará, 2016-06) LOPES, Moisés Oliveira; SILVA, Marcio Roberto Pietrobom da; CARMO, Dimas Marchi do; PERALTA, Denilson Fernandes
(Comparative study of communities of bryophytes in different degrees of flooding in the municipality of São Domingos do Capim, Pará State, Brazil). Third-five transects were analyzed (10 × 10 m) for the floristic survey and eighteen transects (six for each vegetation type: Igapó Forest (IG), Várzea Forest (VA), and Terra Firme Forest (TE)) were randomly analyzed in order to compare the bryophyte communities. We found 118 species: 37 mosses and 82 liverworts Lejeuneaceae (63 species) was the richest among the liverwort families to liverworts and Calymperaceae (eight species) among mosses. The estimated species richness was lower than expected, but the collector’s curve was stabilized. The most colonized substrate was live bark (101 spp., 45 exclusive) followed by decomposing bark (66 spp., 16 exclusive). The results show that the vegetation types analyzed have has differences in bryophyte community richness (IG > TF > VA) and composition, due to the occurrence of exclusive species. The cluster (UPGMA) and ordination (NMDS) analyses indicated the presence of community structure among the three phytophysiognomy.
Acesso aberto (Open Access)
Influência da exploração florestal de impacto reduzido sobre as fases de desenvolvimento de uma floresta de terra firme, pará, brasil
(Universidade Federal do Pará, 2013-12) FRANCEZ, Luciana Maria de Barros; CARVALHO, João Olegário Pereira de; BATISTA, Fábio de Jesus; JARDIM, Fernando Cristóvam da Silva; RAMOS, Edson Marcos Leal Soares
The influence of reduced impact logging were evaluated on the growth phases of a terra firme forest in the Paragominas region, state of Pará, that was logged considering two intensities of timber harvesting. Data were collected in 36 permanent sample plots (0.25ha) randomly distributed among treatments (T1 – Logged forest, harvesting the stem of commercial trees; T2 – Logged forest, harvesting the stem and coarse woody debris) and control (T0 unlogged forest). Three growth phases of the forest were considered: mature (DBH > 40cm); building forest (10cm < DBH < 40cm); and gaps (occurrence of a canopy gap and a few or no tree with DBH > 10cm). The homogeneity of variances of sub-plots between treatments, growth phases and years was tested by the Bonferroni test, according to the statistics of Bartlett and Levene. An analysis of variance was applied on the number of sub-plots by phases, years and treatments at a 0.005 significance level. The Tukey test was applied for analyzing the interaction between the phases and years. Before logging the percentage of growth phases were: 57.0% building forest, 38.9% mature forest and 4.1% canopy gaps. Logging reduced the areas of mature forest and building forest, increasing the number of canopy gaps, but this increase had no statistical difference. One year after logging the area of mature forest (38.4%) and building forest (53.1%) increased while the areas of gaps (8.4%) decreased. Three years after logging the percentage of mature forest (37.1%), building forest (57.9%) and gaps (5.0%) were similar to those found before logging. The forest growth phases were not influenced by logging, over the study period. The study forest showed that it is able to grow, closing the canopy gaps, even in a short period of time.
Acesso aberto (Open Access)
Influência das variáveis ambientais na comunidade de anuros de florestas de Terra-Firme na Amazônia Oriental
(Universidade Federal do Pará, 2013) GONÇALVES, Alinne Nayara Negrão; COSTA, Maria Cristina dos Santos; http://lattes.cnpq.br/1580962389416378
The knowledge of environmental variability assists in predictions about how changes in abiotic environment could affect species distribution. In this study, we evaluated the influence of environmental variables in the composition of frogs communities on local and regional scale from three preserved areas of rainforest mainland: Amapá National Forest, Tapajós National Forest and Caxiuanã National Forest. During the rainy season, between January and April 2012, a total of 56 plots were installed, and we survived for amphibians once on each plot, using simultaneously auditive and visual surveys. The environmental variables collected were: leaf litter height, canopy openness, length at breast height of trees and tree density, air temperature and moisture. In each area the species composition was not affected by canopy openness, leaf litter height and length at breast height of trees. On a regional scale, moisture, temperature, leaf litter height and canopy openness influenced the species composition of the community. The partial redundancy analysis for each area did not indicate significant influence of distance and environmental variables locally, but regionally showed that both distance and environmental variables may influence the community.
Acesso aberto (Open Access)
Quantificação e caracterização química da água da chuva e throughfall e fluxos de gases traço em floresta da terra firme na FLONA Tapajós, Belterra- Pará
(Universidade Federal do Pará, 2006-06-29) OLIVEIRA JÚNIOR, Raimundo Cosme de; RAMOS, José Francisco da Fonseca; http://lattes.cnpq.br/8189651755374537
The Tapajós National Forest, FLONA Tapajós, with 600.000 ha of protected forest is located at the km 50 south of Santarém, Pará, Brazil. Soils are highly weathered and deep, well drained, kaolinitc, classified as Yellow Latosol and according to north American classification as Oxisol (Haplustox), with a acidic pH (4.5) and free of duripans and lateritic concretions. In a ecosystem like a humid tropical forest, nutrients are being cycled. This cycling involves inputs from atmosphere and from the weathering of rocks and minerais present in the soil, with output through drainage water and internai circulation of the system. This circulation involves the transfer of nutrients from vegetation to the soil through the washing (throughfall and runoff on the bole), where there is no intervention by decomposers. Concentrations of ions Cl-, NO3-, PO4-3, SO4-2, Na+, NH4+, K+, Mg+2 and Ca+2 were analyzed by liquid chromatography using a Dionex DX - 120. For gas sampling, stainless steel tubings were installed on the lateral walls of three profiles dig on the ground at the following depths of 5, 15, 30, 50, 100 and 200 centimeters. The concentrations of N20 and CO2 were analyzed by gas chromatography using electron capture detector (ECD), whereas CH4 concentrations were measured using a flame ionization detector (FID). The chromatographs were calibrated using 3 different leveis of synthetic air standards. As results, we observed: The station has strong influence on the basic cation concentration; throughfall is one of the most important ways for nutrient inputs pt the FLONA Tapajós; there is a significant arrival of macronutrients together with Chlorine and sodium coming from the intensive grain agriculture. We observed the greatest volume of precipitation over the last 20 years. Dry deposition is the most important process of water enrichment that reaches the forest soil. The duration of the previous dry period is predominant to determine the input of nutrients into the Tapajós National forest. Within the dry period occur the greatest variations among the ions analyzed. Convection processes that accumulate the nutrients over the FLONA area, due to the breeze of the Tapajós river, favor the increase in the amount of the studied elements; the analyzes of the main components facilitate the interpretation of water characterization from precipitation, showing in this study, the influence of anthropogenic sources (agriculture, biomass burning) and dust; The process of nitrification plays a major role on chemistry,of water from precipitation and should be more studied. About the studied gases, we verified fluxes at a 15 cm depth during the dry period lower than the fluxes observed during the wet period at the same depth. For the other depths, the fluxes during the dry period are always greater than the fluxes during wet period, showing that moisture at depths deeper than 15 cm is enough to promote'the prodúction and emissjon of those gases, not constraining the soil diffusion. We observed sensible seasonal variation among the fluxes of N2O and CO2, with the lowest rates taking place during the dry period. The fluxes, in kg ha-1 year-1, showed 182.1, 22. 97 and 14.08 for CO2, N2O, and CH4, respectively. Strong seasonal variation was observed for soil water content between dry and wet seasons. The soil shows a deficit for available water during dry period when we consider the depth down to 100 cm. At the 100 cm layer down to 200 cm, there was observed no deficit. There was significant correlation between soil water content and N2O flux. No evident variation in soil temperature along the various depths studied. There was no olear seasonal variation in soil temperature between dry and wet periods. Degradable organic material and nitrogen are, together with moisture and soil temperature major factors determining the production and emission of N2O and CO2.
Acesso aberto (Open Access)
Species richness and abundance of low-trunk herb epiphytes in relation to host tree size and bark type, Eastern Amazonia
(2015-06) MAGALHÃES, José Leonardo Lima; LOPES, Maria Aparecida
The composition and structure of the low-trunk epiphytic herb assembly as well as its vertical distribution were studied. DBH of host tree and bark type influence species richness and abundance in a nonlooded lowland tropical rainforest in Eastern Amazonia (1º57’36"S 51º36’55"W). A total of 37 epiphytic herb species were identified, among which 60% were Araceae. Species richness and abundance of epiphytic herbs showed tendency of positive correlation with host tree size and no relationships with bark type. Low positive correlation may be a by-product of the predominance of trees with smaller diameter in our sample rather than a reflection of neutral relationship. The absence of relationships with bark type may be partially explained by the large number of secondary, generalist, hemi-epiphytes and also may reflect the absence of suitable substrate in trees with smaller diameter.