122 research outputs found

    Diversidade florística em dois trechos de Floresta Secundária na Amazônia Oriental, estado do Amapá.

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    The increasing importance of secondary forests all over the world alerts us to the urgent need to understand the biophysical and social underlying factors that affect its regeneration after the abandonment of agricultural practices and natural disturbances. In the state of Amapá, studies related to the structure of secondary forests are still scarce. Therefore, this article aims to characterize the floristic composition and structure in two stretches of secondary forest in the eastern Amazon, state of Amapá. For the floristic and phytosociological study of tree species, 10 plots of 10 x 100 m (1.0 ha) were established: five plots in the community of São Francisco do Iratapuru and five plots in the community of Santo Antônio waterfall, totaling half a hectare (0,5 ha) in each area. In all plots, subjects with diameter at breast height (DBH) ≥ 5 cm were considered. In total, 1,183 subjects were sampled in the two stretches of forest. In stretch 01, 565 subjects belonging to 74 species, 55 genera and 33 families were recorded. In stretch 02, 618 subjects belonging to 26 species, 23 genera and 15 families were recorded. The Shannon diversity index (H'), estimated for stretch 1, was 3.52; and for stretch 2 (2.23). The two studied stretches, despite being registered at the same age, showed significant difference in the species richness, which is the major factor for diversity differences, resulting in low similarity between the studied forests.O reconhecimento do papel das florestas secundárias na manutenção estrutural e funcional da biodiversidade em nível de paisagem e seu potencial ecológico passa pela intensificação dos estudos sobre sua dinâmica, conhecimento florístico e das condições atuais em que elas se encontram em diversas paisagens antropizadas. Este artigo objetivou caracterizar a diversidade florística em dois trechos de floresta secundária na Amazônia oriental, estado do Amapá. Para o estudo florístico e fitossociológico das espécies arbóreas, foram estabelecidas 10 parcelas de 10 x 100 m (1,0 ha): cinco na comunidade de São Francisco do Iratapuru e cinco na comunidade de Santo Antônio da cachoeira, totalizando meio hectare (0,5 ha) em cada área. Em todas as parcelas foram mensurados indivíduos arbóreos com diâmetro a 1,30 cm do solo (DAP) ≥ 5 cm. No total, foram amostrados 1.183 indivíduos nos dois trechos de floresta. No trecho 1 foram registrados 565 indivíduos, distribuídos em 74 espécies, 55 gêneros e 33 famílias. No trecho 2 foram registrados 618 indivíduos, distribuídos em 26 espécies, 23 gêneros e 15 famílias. O índice de diversidade de Shannon para o trecho 1 foi de H’=3,52 e para o trecho 2 foi de H’=2,23. Os dois trechos estudados, embora registrados com a mesma idade, apresentaram expressiva diferença na riqueza de espécies, sendo este o fator preponderante para diferenças de diversidade, culminando com a baixa similaridade entre as florestas estudadas.

    COMPOSITION AND FLORISTIC DIVERSITY OF A PATCH OF THE UPLAND IN SOUTHWESTERN AMAPÁ, EASTERN AMAZON, BRAZIL

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    O objetivo do presente trabalho foi determinar a composição e a diversidade florística de um trecho de floresta de terra firme no Sudoeste do Estado do Amapá, Amazônia Oriental, Brasil. Visando com este estudo, ações de conservação florestal. Para o levantamento, foram distribuídas aleatoriamente 10 parcelas de 10mx100m, perfazendo um hectare. Com auxílio de fita métrica e uma haste de 6m, dividida de um em um metro, foram tomados dados de altura e DAP≥10cm (Diâmetro a Altura do Peito) de todos os indivíduos arbóreos vivos. Neste trabalho, foram registrados 462 indivíduos, pertencentes a 33 famílias e 123 espécies. As espécies com maiores valores de importância (VI) foram, Sclerolobium densiflorum Geissospermum sericeum, Pouteria decorticans, Pentaclethra macroloba e Rinorea racemosa. Na área amostrada, foram encontradas espécies com grande valor comercial e presentes na lista de espécies ameaçadas, dentre elas: Aniba rosaedora (Pau rosa), Vouacapoua americana (Acapú) e Bertholethia excelsa (Castanheira). A presença das referidas espécies é um indicativo de qualidade e conservação ambiental.Palavras-chave: Vegetação, Biodiversidade, fitossociologia.The purpose of this study was to determine the composition and floristic diversity of a stretch of upland forest in southwestern Amapá State, eastern Amazon, Brazil. Aiming to this study, the actions of forest conservation. For the survey, 10 parcels were randomly distribuited in 10mx100m, making an hectare. Along with a tape and a six-meter-long rod, divided into meter by meter data and DBH≥10cm (Diameter at Breast Height) of all living individual trees were taken. In this study, 462 individuals belonging to 33 families and 123 species were recorded. The species with the highest importance values (IV) were, Sclerolobium densiflorum, Geissospermum sericeum, Pouteria decorticans, Pentaclethra macroloba and Rinorea racemosa. In the sampled area, species with high commercial value and present in the list were found of endangered species, among them: Aniba rosaeodora (Pau rosa), Vouacapoua americana (Acapu) and Bertholethia excelsa (Chestnut). The presence of such species is an indicator of quality and environmental conservation.Keywords: Vegetation; biodiversity; phytosociology

    MORFOMETRIA DAS FIBRAS DO SISTEMA RADICULAR DE Philodendron bipinnatifidum SCHOTT (FAMÍLIA ARACEAE; SUBGÊNERO MECONOSTIGMA).

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    Philodendron bipinnatifidum presents dimorphic roots, where two patterns of aerial roots: fixed and suspended. The root is broken down into two parts: air, ground. This study aims to determine the anatomical and micrometric fibers of the roots of P. bipinnatifidum with the goal of providing subsidies to paper industry. To carry out the measurement of some variable anatomic root portions thereof suspended in air, air-ground and ground-side 10 adults were analyzed, and in each five samples taken from a total of 50 measurements for each variable. Were analyzed: fiber (length, width, thickness and lumen diameter material-decoupled), the total thickness of the root cortex and stele (cross sections). Data were subjected to analysis of variance and the averages compared by Tukey test at 5% probability. Analyzing the statistical data collection is concluded that the fibers of the three portions of the roots examined do not complete the requirements necessary to achieve a quality paper. Although some values are significant portion of the lateral root-underground indicating that they may submit a paper with good strength and stiffness over, would not be economically feasible due to the difficulty of obtaining these roots.Keywords: Dimorphism; fibers; aerial root; root underground.Philodendron bipinnatifidum apresenta raízes dimórficas, onde ocorrem dois padrões de raízes aéreas: fixas e suspensas. A raiz suspensa é dividida em duas porções: aérea, subterrânea. Esse estudo visa determinar características anatômicas e micrométricas das fibras das raízes de P. bipinnatifidum com o objetivo de fornecer subsídios para indústria de papel. Para se proceder a quantificação de algumas variáveis anatômicas da raiz suspensa nas suas porções aérea, aérea-subterrânea e lateral-subterrânea, 10 indivíduos adultos foram analisados, sendo, de cada, retiradas cinco amostras num total de 50 medições para cada variável. Foram analisadas: fibras (comprimento, largura, espessura de parede e diâmetro do lume- material dissociado), espessura total da raiz, do córtex e do estelo (secções transversais). Os dados obtidos foram submetidos à análise de variância e suas médias comparadas através do teste de tukey ao nível de 5% de probabilidade. Analisando os dados estatísticos em conjunto concluiu-se que as fibras das três porções das raízes analisadas não completam as exigências necessárias para alcançar um papel de qualidade. Apesar de alguns valores serem significativos para porção da raiz lateral-subterrânea indicando que as mesmas podem apresentar um papel com boa resistência e mais rigidez, porém economicamente não seria viável pela dificuldade de obtenção dessas raízes.Palavras-chave: Dimorfismo, fibras, raiz aérea, raiz subterrânea

    Litter flux in a successional forest ecosystem under nutrient manipulation in Eastern Amazon / Fluxo de serapilheira em um ecossistema florestal sucessional sob manipulação de nutrientes na Amazônia Oriental

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    The aim of this work was to evaluate the dynamics of Ca and Mg cations, via litter, in a successional forest ecosystem, on the middle plateau of the Apeú river, in Castanhal, northeast of Pará (1º19’ S, 47º57’ W). The magnitude of this phenomenon can be explained by the functional role of the floristic structure, with dominant species, Myrcia sylvatica (G. mey) DC., Myrcia bracteata (Rich) DC., Miconia ciliata (Rich) DC., Lacistema pubescens Mart., Lacistema aggregatum (Berg.) Rusby, Vismia guianensis (Aubl.) Choisy, Cupania scrobiculata Rich. and Ocotea guianensis Aubl, which consisted in the determinant factors, associated to the natural hydroperiodic effect. The evaluation  of analytical results, in litter removal treatment, of the mean mass of Ca ranged from 0.018 to 0.076 g m-2month-1, while Mg varied from 0.006 to 0.028 g m-2month-1, being significantly (P<0.05) different from control in treatment and time. However, the flux distribution was influenced by the season, being higher in the dry period. The flux values of Ca (0.047 ± 0.015 g m-2month-1) were significantly higher (P<0.05) than those of Mg (0.015 ± 0.004 g m-2month-1), independently of the manipulation via treatment, phenomenon explained by the dynamics of Calcium in the biogeochemical cycle

    COMPOSITION AND STRUTURE OF DENSE OMBROPHYLOUS FOREST IN THE EXTREME NORTH OF THE STATE OF AMAPÁ, BRASIL

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    Neste artigo é apresentado a fitossociologia e florística de um fragmento de Floresta Ombrófila Densa no extremo Norte do Brasil, com árvores de CAP ≥ 33cm. Os dados foram coletados em 17 parcelas de 20m x 100m distribuídos aleatoriamente na área de estudo. Foram registrados 1804 indivíduos distribuídos em 30 famílias, 70 gêneros e 93 espécies. As famílias Fabaceae e Lauraceae destacaram-se em todos os parâmetros fitossociológicos analisados, assumindo a primeira e segunda posição em riqueza, densidade, dominância e frequência. Protium pubescens destacou-se como a espécie mais importante com 24,59 de IVI, como também a que apresentou o maior número de indivíduos na comunidade (144), seguida de Dipteryx odorata com 13,99 de IVI e 43 indivíduos e Hymenaea courbaril, com 11,45 de IVI e 29 indivíduos.Palavras-chave: florística, fitossociologia, Amazônia.This paper presents the floristic and phytosociological fragment of a Tropical Rain Forest in the extreme North of Brazil, with trees CBH ≥ 33cm. Data were collected on 17 plots of 20m x 100m randomly distributed in the study area. We recorded 1804 individuals belonging to 30 families, 70 genera and 93 species. Lauraceae and Fabaceae families stood out in all phytosociological parameters analyzed, assuming the first and second position in richness, density, dominance and frequency. Protium pubescens stood out as the most important species with 24.59 of IVI, as well as the one with the largest number of individuals in the community (144), followed by Dipteryx odorata 13.99 of IVI and 43 individuals and Hymenaea courbaril, with 11,45 of IVI and 29 individuals.Keywords: Floristic; Phytosociology; Amazon

    Padrão de distribuição espacial e estrutura diamétrica de Protium Burm. F. na reserva de desenvolvimento sustentável do rio iratapuru, Amapá, Brasil

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    The present work aims to determine the spatial distribution pattern of Protium Burm. f and the diametric structure of these species in a dense tropical submontane rainforest along the Sustainable Development Reserve (SDR) of the Iratapuru river. The area of study was divided into three plateau compartments called Mane Preto Sierra, Banco Grande Sierra and Alaska Sierra. In each plateau compartment it was settled a single area transect with 1,000 x 20 m, where DAP ≥ 10 cm of the entire Protium population within the transects was measured. The data was processed in the specific software Mata Nativa 2. There were inventoried Protium tenuifolium, Protium altsoni, Protium polybotryum subsp. blackii and Protium paniculatum var. riedelianum. Most individuals concentrated in smaller diametric classes, decreasing progressively to a lesser extent in larger classes. It can be concluded that the population has medium size and its vertical structure is characterized by the presence of three strata, however, its phytocenoses is defined by two clear constants: the first groups individuals of up to 15 m of height and forms the uniform and dominant stratum; the second is composed by emerging up to 35 m high and whose diameter structure shows a population in dynamic balance. © 2018, Eduem - Editora da Universidade Estadual de Maringa. All rights reserved

    Composição, estrutura e diversidade florística em floresta ombrófila densa na Amazônia Oriental, Amapá, Brasil

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    This study aims to evaluate the phytosociology and floristic composition of tree species in the eastern Amazon, at the Iratapuru River Sustainable Development Reserve (RDS), State of Amapá. Fouteen quarters with dimensions of 100 m x 100 m were randomly inventoried, and 50 sub-plots of 10 m x 20 m were established. In each sub-plot all living individuals were sampled, being taken from the height data and DAP (breast height diameter) for tree species ≥ 10 cm. A total of 5,233 individuals belonging to 33 families and 184 species were registered. The families with the largest number of species were Fabaceae (32), Lauraceae (17), Sapotaceae (12), Moraceae (10), Lecythidaceae (8) and Annonaceae (8). The six most abundant families (18.18% of total families) in the present study were responsible for more than half (57.92%) of the total number of species. The floristic structure of the area studied was diverse, with species of varied interests, including: medicinal, timber and oil-producing. © 2015 Eduem - Editora da Universidade Estadual de Maringa. All rights reserved

    Composition, diversity, and structure of tidal “Várzea” and “Igapó” floodplain forests in eastern Amazonia, Brazil

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    The objective of this study was to evaluate the composition, diversity, and structure of tidal “Várzea” and “Igapó” forests in eastern Amazonia, Amapá, Brazil. All live tree individuals with diameter at breast height (dbh) ≥10 cm were registered. A total of 130 plots measuring 10 × 100 m were inventoried, distributed among 13 ha in each of the two forest typologies. A total of 10,575 trees were reported, belonging to 343 species, 172 genera, and 49 families. For all 26 ha sampled, mean tree density was 406 ± 61.27 trees ha−1 and mean basal area was 27.2 ± 11.13 m2 ha−1. Fabaceae, Arecaceae, Malvaceae, Meliaceae, and Rubiaceae were the most important families in tidal “Várzea”, together accounting for 74.76 % of the family importance value index (FIVI %). In “Igapó”, the most important families were Lecythidaceae, Euphorbiaceae, Malvaceae, and Arecaceae, which together accounted for 57.05 % of the family important value index (FIVI %). Smaller diameter trees measuring between 10 and 30 cm dbh dominated the landscape, accounting for 75.52 % of all individuals sampled. In general, 80 % (8285) individuals were under 24 m in height, while only 1.32 % of trees (140) reached heights above 34 m. There was evidence for statistically significant mean differences among tidal “Várzea” and “Igapó” with regard to the number of individuals, species, diversity, and tree height. However, no mean differences were detected for equitability, dbh, dominance, and basal area. Compositional patterns showed low similarity between the evaluated areas, indicating the existence of phytogeographic pattern based on species distribution. © 2016, Botanical Society of Sao Paulo
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