João Marcelo Alvarenga Braga

Bio: João Marcelo Alvarenga Braga is an academic researcher from State University of Norte Fluminense. The author has contributed to research in topics: Marantaceae & Dioscorea. The author has an hindex of 12, co-authored 49 publications receiving 415 citations.

Estrutura e composição florística do estrato arbóreo de um remanescente de Mata Atlântica submontana no município de Rio Bonito, RJ, Brasil (Mata Rio Vermelho)

Abstract: Neste trabalho, descreveram-se a composicao floristica e a estrutura do estrato arboreo de um remanescente de Floresta Ombrofila Densa Submontana (Mata Rio Vermelho) na regiao Centro-Norte fluminense, comparando-a com outras florestas da regiao. Foram alocadas oito parcelas de 5 m x 100 m, e todos os individuos vivos e mortos com DAP > 5 cm foram amostrados. Ao todo, foram registradas 106 especies pertencentes a 77 generos e 32 familias. As familias com maior riqueza de especies foram Leguminosae (13 especies) e Lauraceae (8), e as mais abundantes foram Monimiaceae (13% dos individuos) e Leguminosae (11%). As especies mais importantes quanto ao valor de cobertura (VC) foram Siparuna guianensis, Apuleia leiocarpa, Cupania oblongifolia e Machaerium brasiliensis, todas caracteristicas de areas secundarias. O indice de diversidade de especies (H' = 3,91 nats.ind-1) foi proximo ao encontrado em outras florestas secundarias. Os resultados (elevado numero de arvores mortas, com lianas, perfilhadas e secundarias iniciais; baixo numero de arvores de grande porte e area basal) indicaram que a mata em foco se encontrava perturbada e em fase de regeneracao intermediaria. Ainda assim, permanecia detentora de consideravel riqueza e diversidade floristica, com especies arboreas ameacadas de extincao, como Melanoxylon brauna e Dalbergia nigra. Devido a importância ecologica desde remanescente para a manutencao da flora e fauna local e ao avancado processo de fragmentacao da regiao, sugere-se que a Mata Rio Vermelho seja prioritaria em programas de conservacao e manejo.

Composição e riqueza florística do componente arbóreo da Floresta Atlântica submontana na região de Imbaú, Município de Silva Jardim, RJ

Abstract: O presente trabalho teve por objetivo avaliar a composicao floristica arborea de um trecho de Floresta Atlântica submontana na regiao de Imbau, Silva Jardim, RJ. Esta regiao formava um continuo florestal que foi fragmentado ha mais de 50 anos por praticas agropecuarias. Cinco fragmentos foram selecionados e em cada um deles foram alocadas quatro parcelas de 100×5 m. Todas as arvores vivas com DAP > 5 cm foram amostradas e identificadas. No hectare amostrado foram encontradas 161 especies distribuidas por 39 familias. A similaridade floristica entre os fragmentos foi alta, com indice de Morisita variando de 0,36 a 0,79. As familias Leguminosae, Lauraceae e Rubiaceae apresentaram a maior riqueza de especies. A comparacao floristica com uma floresta madura da regiao indicou forte decrescimo na riqueza de especies que, juntamente com a elevada densidade de especies secundarias iniciais, indicam que estas matas se encontram em estadio sucessional secundario. Analisando a similaridade floristica entre a regiao de Imbau e outras 17 florestas do Rio de Janeiro, observou-se maior similaridade com as florestas submontanas mais proximas geograficamente. Devido ao avancado processo de fragmentacao e a importância ecologica destes fragmentos para a manutencao da flora e fauna, sugere-se que a regiao de Imbau deva ser prioritaria em programas de conservacao e manejo de areas de Mata Atlântica.

Past land-use and ecological resilience in a lowland Brazilian Atlantic Forest: implications for passive restoration

Abstract: The ecological resilience of abandoned pastures has important implications for the potential of passive restoration in the Brazilian Atlantic Forest, especially in the face of the ambitious restoration targets for this biodiversity hotspot. In the present study, we aimed to investigate the influence of past land-use on natural regeneration in two secondary forests that established on abandoned pastures with different land use histories (Abandoned + Fire—15 years since the last fire event and Abandoned—36 years ago) in a lowland Brazilian Atlantic Forest. Both secondary forests exhibit low resilience for the three analyzed attributes: vegetation structure, richness, and species composition. Secondary forests affected by fire have the lowest values for species richness, aboveground biomass and leaf area index compared to old-growth forests. Secondary forests were dominated by Moquiniastrum polymorphum—Asteraceae, which was absent from the old-growth forests. Fire resistance, capacity to establish in nutrient-poor soils and efficient seed dispersal in human-modified landscapes are important attributes that may explain the dominance of this species. We demonstrate that even in sites considered appropriate for passive restoration a priori (e.g. located in a protected area, 36 years since abandonment and close to old-growth forests), secondary forests exhibited low aboveground biomass and communities were dominated by few species. Therefore, our results highlight the effects of past land-use on natural regeneration and suggest the necessity to use interventions such as enrichment plantings, nucleation techniques and assisted natural regeneration in order to accelerate forest restoration.

Insect galls from Atlantic Forest areas of Santa Teresa, Espírito Santo, Brazil: characterization and occurrence.

Abstract: Galhas de insetos de areas de Mata Atlântica de Santa Teresa, Espirito Santo, Brasil: caracterizacao e ocorrencia. Tres areas protegidas de Mata atlântica foram investigadas em Santa Teresa, Espirito Santo, de junho de 2007 a agosto de 2009: Estacao Biologica de Santa Lucia, Reserva Biologica Augusto Ruschi e Parque Natural Municipal Sao Lourenco. A vegetacao local foi examinada a procura de galhas de insetos. Foram encontrados 265 morfotipos de galhas em 141 especies de plantas (104 generos e 49 familias). Asteraceae, Fabaceae, Myrtaceae, Melastomataceae e Rubiaceae foram as familias de planta com maior riqueza de galhas. Os generos super-hospedeiros foram Mikania Willd. (Asteraceae), Myrcia DC. ex. Guill. (Myrtaceae) e Inga Mill. (Fabaceae). A especie super-hospedeira foi Guapira opposita (Vell.) Reitz. (Nyctaginaceae). As galhas foram encontradas em folhas, caules, botoes, raizes e gavinhas. As folhas foram o orgao vegetal mais galhado, seguidas pelos caules e botoes. Os indutores pertencem a quatro ordens de insetos: Diptera, Lepidoptera, Hemiptera e Thysanoptera, sendo Cecidomyiidae (Diptera) os mais frequentes e diversificados galhadores. Inquilinos foram obtidos de seis morfotipos de galhas, estando representados por Cecidomyiidae and Muscomorpha. Nove species galhadoras sao registradas pela primeira vez no Estado do Espirito Santo, e Cordiamyia globosa Maia, 1996 e assinalada pela primeira vez para o municipio de Santa Teresa. O presente estudo indica Santa Teresa (ES) como a area de Mata Atlântica com maior riqueza de galhas de insetos.

The natural impact of banana inflorescences (Musa acuminata) on human nutrition

Abstract: Banana inflorescences are popularly known as 'navels,' and they are used in Brazil as nutritional complements. However, the nutritional value of banana inflorescences (male flowers and bracts) has never been studied. Therefore, plant material of Musa acuminata, cultivar "ouro", was collected in Rio de Janeiro state, Brazil, and then submitted to chemical procedures to determine its nutritional composition. The experiment was arranged a completely randomized design and performed in triplicate. The sample composition analysis showed percentual average value for moisture, protein, fat and ash as 8.21, 14.50, 4.04 and 14.43, respectively. The dehydrated inflorescences were found to contain a significant nutritive complement based on their high content of potassium (5008.26 mg / 100 g) and fiber 49.83% (lignin, cellulose and hemicelluloses) revealing important functional and nutritional properties. In a parallel evaluation, the anatomical study revealed key elements for the recognition of Musa acuminata when reduced to fragments.

International Treaty on Plant Genetic Resources for Food and Agriculture

Abstract: The International Treaty on Plant Genetic Resources for Food and Agriculture, referred to as the Plant Treaty, was approved on 3 November 2001 by Members of the Food and Agriculture Organization (FAO), headquartered in Rome, Italy. The FAO is an agency of the United Nations, headquartered in New York City, New York. The Plant Treaty established international standards for the conservation and exchange of plant genetic material between participating countries. Plant genetic material is a term for plant germplasm, the physical material used by plants to reproduce themselves, and the term connotes seeds, vegetative propagations, and DNA. Plant genetic resources are the collective genetic diversity of plant species in the laboratory, farm, and field. They are described as resources because of their value for food and agricultural purposes.

An overview of the anatomy, development and evolution of the vascular system of lianas

Abstract: Background: Lianas present many interesting structural features that are linked to their climbing habit. Having lost substantial amounts of supporting tissue, these plants depend on external structures for support. Meanwhile, during their evolutionary history, they have gained additional conductive and storage tissues. The wood of lianas generally includes wider vessels, larger amounts of axial parenchyma, larger rays, and longer fibres than those of trees. Cambial variants represent another key anatomical feature of lianas. Aims: In this paper, we review various aspects of liana biology, including those associated with their vascular system and water conduction, secondary growth and seasonal responses to environmental variability, as well as aspects related to the evolution of their cambial variants. Methods: Examples from the Bignoniaceae and Leguminosae, the two most abundant liana taxa in the Neotropics, are presented in a series of case studies, bringing new data, such as the activity of the cambium ...