ChapterPDF Available

Distribuição das chuvas em Roraima

Authors:
... The island is located in the southern portion of the Guiana Shield, where mosaics of ombrophilous and seasonal forests are found in contact with the large area of savanna in the northern Brazilian Amazon (Milliken and Ratter, 1989). According to Köppen's classification, Maracá is a humid tropical climate (A) and represents a transition from the subtype savanna or tropical climate with a dry winter season (Aw) to the monsoon subtype (Am) (Barbosa, 1997). Based on data from the Maracá agrometeorological station , the average annual temperature is 26 °C, and annual precipitation is 2,086±428 mm, with the wettest months (>300 mm month -1 ) are from May to August and the driest months (<100 mm month -1 ) from December to March (Carvalho et al., 2018). ...
Article
Full-text available
The ecotone forests in the northern region of Brazilian Amazonia are important areas representing transition zones between forest and non-forest ecosystems. These areas have soils nutrient-poor that poorly drain. Under these environmental conditions, Peltogyne gracilipes (Leguminoseae), an endemic tree species, can form natural monodominant forests. Here, we assessed the arbuscular mycorrhizal fungi (AMF) community in three forest types on the eastern side of Maracá Island and the relationship of these microorganisms with the monodominance of P. gracilipes. In this study, soil samples were collected in two seasons (dry and rainy). The samples were collected in 9 plots, in rich areas, poor areas and areas without P. gracilipes. Soil samples were evaluated for chemical and particle size analysis, spore density and morphology, and identification of AMF. AMF species were identified using two approaches: spores collected in the field and trap cultures. Eighteen and 13 AMF species were identified in the dry and rainy seasons, respectively, for spores extracted from the field. Six total species were detected exclusively in trap cultures in the dry season. AMF communities were co-dominated by members of the Gigasporaceae, Acaulosporaceae and Glomeraceae families. Redundancy analyses indicated that several soil attributes, such as pH, Fe, Mg, and sand content associated with the AMF species richness in both seasons. We conclude that the ecotone forests in the eastern region of Maracá Island are home to important richness and diversity of AMF species and that various soil factors influence the composition of the AMF community in this ecosystem.
... The study area (03°04'15"N, 60°48'44"W) approximately 440 km 2 is located 35 km northwest of Boa ACTA AMAZONICA Vista, the capital of Roraima, northern Brazil ( Figure 1). Annual rainfall ranges from 1,500 to 1,700 mm and mean temperature is 27.8 ± 0.6 ºC (INMET 2018), with a Aw climate (Köppen classification), typical of the savanna areas of the northern Brazilian Amazon (Barbosa 1997). ...
Article
Full-text available
Forest fires incorporate pyrogenic organic matter into the soil, affecting the characteristics of soil organic matter (SOM) due to its high aromaticity, increasing its renewal time. However, the factors that control the concentration of pyrogenic organic matter and its chemical composition and structure are still little known. Forest fragments dispersed in a savanna matrix of the northern Brazilian Amazon are frequently impacted by fires, which can affect the composition of SOM within the fragments. The aim of this study was to analyse the chemical composition of SOM in the border and interior of six forest fragments in the Roraima savanna, in the northern Brazilian Amazon. Soil samples were collected at 10-cm intervals up to 1 m in depth at the border and in the interior of each fragment. Soil organic material concentration was determined with 10% HF solution and its elemental composition, thermogravimetric index, and 13C CPMAS NMR spectroscopic analysis were determined. There was no significant difference in the aromaticity index between border and interior. The concentration of alkyl C structures between border (22 to 25%) and interior (19 to 29%) indicated the occurrence of medium-intensity fires in the study area. The thermogravimetric analysis showed no significant difference in the thermal stability of SOM between border and interior. Our results showed no pronounced difference in SOM quality up to 1 m depth between the border and the interior of the evaluated forest fragments, indicating that this compartment is stable throughout the fragments.
... This study was performed in eastern of Maracá Island, the largest part of the Maracá Ecological Station (3° 15' -3° 35' N and 61° 22' -61° 58' W), a conservation area managed by the Chico Mendes Institute for Biodiversity Conservation (ICMBio) located in state of Roraima, Northern Brazilian Amazonia (Figure 1). Maracá has moist tropical climate, and it is situated in a region characterized by the transition between savanna (Aw) and monsoon (Am) climatic subtypes in Köppen's classification (Barbosa, 1997;Barni et al., 2020). Average annual temperature and rainfall are 26 °C and 2.086 ± 428 mm, respectively, with a rainier period from May to August, and a drier period from December to March (Couto- Santos et al., 2014). ...
Article
Full-text available
The structure of tree communities in tropical forests depends on environmental filters and biotic interactions such as competition and facilitation. Many ecotone forests in Northern Amazonia are intriguingly populated by tree assemblages characterized by distinct abundances of a single species, Peltogyne gracilipes (Leguminosae). It is unclear whether this pattern solely reflects environmental filters or also antagonistic interactions among species with similar habitat requirements. The aim of this study was to determine the response of species richness and composition to environmental filters, and analyze the role of P. gracilipes in structuring tree communities in ecotone forest areas of the Northern Brazilian Amazonia. We sampled 129 permanent plots along a hydro-edaphic gradient. All arboreal individuals with stem diameter ≥10 cm were measured and identified. Multiple regressions were performed to test the effects of environmental filters, and abundance of P. gracilipes on the tree species richness and composition. Species richness and composition responded to the same filters which, in turn, affected species composition directly and indirectly, through the abundance of P. gracilipes. Our results indicate that both abiotic filters and biotic interactions shape the studied tree communities. P. gracilipes can be considered an indicator species of hydro-edaphic conditions, but also is itself a driver of tree community structure.
... km 2 , representando 2,6% do território brasileiro (Iteraima, 2005). O Estado apresenta uma vegetação de savana e tipo climático Aw no nordeste, uma vegetação de florestas úmidas de baixo relevo e tipo climático Af no sudoeste e, entre as duas regiões, uma faixa de transição savana-floresta-floresta de altitude, com tipo climático Am (Barbosa, 1997 (Brasil, 2000). Essas são fundamentais para a conservação in situ dos distintos graus de interações ecológicas, incluindo os sistemas e meios tradicionais de sobrevivência de comunidades humanas (Medeiros et al., 2011). ...
Article
Full-text available
Roraima is a state in the North of Brazil that has seven Conservation Units, of which only three have information about the social wasp fauna. The objective of the study was to register the social wasps that occur in the Floresta Nacional de Roraima Conservation Unit. Passive collections were carried out during 2018 with the Malaise trap, with the removal of the material monthly. Twenty-five species were collected, with two new records for Roraima. This study brings the first information about the social wasp fauna of the Conservation Unit and contributes to the knowledge of the taxon in the State.
... W; Supplementary Figure S1). The average annual temperature in the region is 26 • C, and precipitation ranges from 1,700 to 2,000 mm year −1 (Barbosa, 1997). The Serra da Lua region is part of the "Lavrados de Roraima" (also known as the Guyana savannahs), the second largest block of Amazonian savannah . ...
Article
Full-text available
Across the globe, millions of hectares of native vegetation have been replaced by commercial plantations, with negative consequences for biodiversity. The effects of the replacement of native vegetation with commercial plantations on the functional and phylogenetic diversity of bat assemblages remain understudied, and most studies have focused exclusively on the taxonomic component of diversity. Here, we investigate how the replacement of natural savannahs by acacia plantations affects the α-and β-diversity of bat assemblages. We sampled bats, using mist-nets at ground level, in natural forest, savannah areas and acacia plantations, in the Lavrados de Roraima in the northern Brazilian Amazon. Our results show that, in general, acacia is less diverse than native forests in terms of taxonomic and functional diversity, and is also less taxonomically diverse than the savannah matrix which it substitutes. The observed patterns of α-and β-diversity found in the present study are in large part driven by the superabundance of one generalist and opportunistic species, Carollia perspicillata, in the acacia plantations. Taken together, our results show that the replacement of areas of natural savannah by acacia plantations causes a regional loss in diversity across all diversity dimensions: taxonomic, functional and phylogenetic. However, further studies are required to fully understand the ecological and conservation implications of this landscape change.
Article
Full-text available
Este trabalho apresenta um panorama do conhecimento disponível sobre a pesca comercial na bacia do rio Branco, concentrandose principalmente no seu trecho inferior, o baixo rio Branco, a mais importante área de pesca do estado de Roraima. Destacamos os aspectos mais relevantes da exploração dos recursos pesqueiros nesta bacia ao longo de mais de duzentos anos, incluindo o estabelecimento pela coroa Portuguesa dos "pesqueiros reais", os relatos dos naturalistas que contribuíram com o conhecimento sobre a ictiofauna local, uma caracterização da pesca comercial atualmente praticada na região, e uma análise histórica sobre a influência que a criação de dois parques nacionais e duas estações ecológicas, unidades de conservação de proteção integral, impuseram à prática da atividade pesqueira no baixo rio Branco. Apresentamos ainda uma compilação inédita de informações e uma análise sobre o desembarque pesqueiro em Roraima, desde o primeiro dado disponível, de 1962, para o então Território Federal do Rio Branco, até 2011, último ano em que se tem estatística oficial para o Estado. Concluímos com um breve vislumbre sobre o que se espera para o futuro da atividade pesqueira em Roraima, incluindo as muitas mudanças que estão ocorrendo em toda a bacia do rio Branco e a falta, ou escassez, de políticas públicas que contemplem a pesca.
Chapter
Full-text available
Estudos etnobotânicos buscam resgatar o conhecimento botânico tradicional quanto ao uso e manejo dos recursos vegetais, enfatizando a participação de comunidades locais para melhor elaboração de estratégias de conservação. Desta forma, foi realizado um levantamento etnobotânico por meio de entrevistas semiestruturadas com 60 participantes (36 homens e 24 mulheres) de 38 famílias, entre 18 e 84 anos de idade na Comunidade Indígena Darora, etnia Makuxi, na Terra Indígena São Marcos, aos quais os foram arguidos sobre as espécies arbóreas presentes na região e seus usos.Também foi realizado um levantamento florístico e fitossociológico para verificar a disponibilidade dos recursos lenhosos. As respostas foram agrupadas nas categorias Alimentação (inclui Ração Animal), Artesanato, Combustível, Construção, Medicinal e Tecnologia e as espécies tiveram seus valores de uso e parâmetros fitossociológicos calculados. Quatro espécies arbóreas apresentaram destaque na Comunidade mostrando ao menos em cinco das seis categorias, Cassia moschata Kunth (marimari), Copaifera pubiflora Benth. (copaíba), Genipa americana L. (jenipapo) e Mauritia flexuosa L. f. (buriti). A copaíba (Copaifera pubiflora) e o marimari (Cassia moschata) foram as únicas espécies associadas a todas as categorias de uso, embora ambas tenham se destacado principalmente na categoria Construção. Copaifera pubiflora também teve grande destaque na categoria Medicinal e o Cassia moschata na categoria Tecnologia. Espécies de uso múltiplo na Comunidade Darora reconhecidas aqui chamaram a atenção pelos baixos valores de disponibilidade no ambiente. No entanto, destas espécies, Copaifera pubiflora e Mauritia flexuosa foram as que apresentaram maiores valores de uso, indicando um maior conhecimento e potencial uso pelos moradores.
Chapter
Corporate Social Responsibility (CSR) is the continuous commitment of organizations to ethics and economic development, while contributing to improving the quality of life of workers, their families and the local community, as well as society, thus revealing the human side of business (Holme and Watts 2000). Similarly, ergonomics in their macro hang has its nature in human behavior and interactions between man and the socio-technical system in which it is inserted. In its macroergonomic approach, it intends to optimize the relationship between man, organization, technology, environment and people (Guimarães 1999). Among the applications of macroergonomics, the Macroergonomic Analysis of Work (MAW), presents itself as an application method proposing, implementing and evaluating changes in a participatory way in the work environment. It is understood that CSR and ergonomics can work together contributing to the promotion of sustainable development in organizations. That said, this study aims to propose a theoretical framework demonstrating the intersections between CSR and ergonomics and their validation in the health context. For that, construction and application of the theoretical scheme was carried out in the case study of Sasaki and Leite (2018) in a hospital sector. It is concluded that CSR and ergonomics can act in a complementary way and contributing to Sustainable Development.
Thesis
Full-text available
Fire is one of the main factors leading to forest degradation in the Amazon by changing species composition, biomass and structure. Considering the (potential) geographical scale of forest fires, remote sensing provides essential data for mapping, monitoring and even modeling. Despite radar sensors gather information on forest structure, no study based on such data mainly focused on fire affected areas in the Brazilian Amazon. The study area was situated in the “Arc of Fire”, in the State of Roraima (Northern Amazonia), where 50 plots (0.25 ha each) were set out. We aimed to model the aboveground biomass (AGB) as a function of polarimetric attributes and to characterize the forest degradation from these attributes. The impacts of understory fires on species composition, stand structure and AGB were also assessed. Field and polarimetric data analyses provided concordant results, revealing that frequent fires promoted a ‘secondarization’ of primary forests. Tree species diversity was significantly reduced after recurrent fires. Even after a 12 years post-fire of a single fire, some units were still dominated by Cecropia spp. Significant differences were found on stand structure (density, height, basal area) between fire degradation levels, particularly in thrice burned forests. The AGB stocks were reduced by 60% and similar to values previously reported for secondary forests in the same region. Forests that experimented frequent fire showed lower entropy and the presence of surface scattering was emphasized in the H/ plane. The polarimetric responses indicated the dominance of the VV polarization scattering in primary and lightly burned forests, whereas a dominance of the scattering in HH polarization was noted in heavily and frequent burned forests. The results suggests that polarimetric coherent and incoherent attributes (ψ2, A, Pd, VSI) are both important in modeling AGB in forests characterized by a fire history (R²=0.76; RMSE=32.1 Mg.ha-1 or 27.8% of the mean). No saturation point was detected for the estimates as the AGB values were predicted up to 300 Mg.ha-1. This was attributed to the inclusion of coherent parameters in the model. The model cross-validation (leaveone-out) showed a RMSE equal to 36.6 Mg.ha-1 (31% of the mean). We found an adjusted R² of 0.7 and a RMSE of 32.45 Mg.ha-1 (23% of the mean) in the model validation from independent set of samples (hold-out). We thus confirmed that the fullpolarimetric data used in biomass studies are sensitive to the fire degradation level. The high vulnerability of Northern Amazonia tropical forests to fire was also verified. Finally, we underlined the importance of field data collection and analyze as they provide valuable insights to understand the target itself and how it interacts with the radar microwaves.
Chapter
The residents around Rufina beach are an unique case of knowledge and experience in a fluvial ecosystem of great ecological relevance in Amazon, vital source to the planet and an important subject for all citizens. Currently, it is also a focus of study in several areas of natural and human sciences, in particular due to the specific role that women play in society. Natural resources, such as forest, soil and water, impose themselves as immediate targets for preservation, particularly by residents who daily experience tourism and withdraw their livelihood from these waters. In line with the goal 14 of the Sustainable Development Goals (SDGs), by United Nations (UN), a global appeal to sustainability in general, this research aims to describe survival and tourism actions in the sparsely populated region located in Mucajaí, RR, Brazil, addressing the important actions of women in this region. The descriptive methodology is directed to the attitudes of citizens around the Mucajaí River. For a good resource management, an awareness raising meeting has stimulated actions to minimize the aesthetic stress on the aquatic landscape, a negative factor for geotourism, and which has as its principle conservation the inclusion of local citizens. It can be concluded that awareness and ecologically correct attitudes, such as the reduction of river pollution, guarantee social and environmental sustainability for all.
ResearchGate has not been able to resolve any references for this publication.