66 research outputs found

    FITOSSOCIOLOGIA DE UMA FLORESTA DE TERRA FIRME NA AMAZÔNIA SUL-OCIDENTAL, RONDÔNIA, BRASIL

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    The present study reports floristic composition and phytosociology in 1ha 30 permanent plots of a Terra Firme Forest at South-Western Amazon, inserted at a PPBio’s grid, considering trees DBH ≥ 1cm. 10678 individuals were registered, 89,1% trees and 10,9% palms, belonging to 47 families and 140 genera, within 74 identified at species level. Chrysobalanaceae, Arecaceae, Fabaceae, Rubiaceae, Lecythidaceae and Burseraceae showed highest values of IVIF. Fabaceae, Arecaceae, Moraceae, Rubiaceae, Melastomataceae and Urticaceae were most representative in terms of species richness, gathering 42% of local richness. The Shannon-Wiener diversity (H’ = 3.81) and Sorensen floristic similarity (6-81%) índices suggest that the forest environment is not very diversified considering Amazon biome, although presenting high variability of species composition between plots.Keywords: Phytosociology; biodiversity; ESEC Cuniã; PPBio; Southwestern Amazon.Este artigo reporta a florística e fitossociologia de 30 parcelas de 1 ha em uma floresta de Terra Firme na Amazônia Sul-Ocidental, inseridos em uma grade PPBio de 25km² e considerando-se indivíduos de DAP ≥ 1cm. Foram registrados 10679 indivíduos, sendo 89,1% árvores e 10,9% palmeiras, referentes a 196 táxons, dos quais 176 foram identificados em nível específico, distribuídos em 47 famílias e 136 gêneros. Quanto ao Índice de Valor de Importância Familiar (IVIF), os maiores valores foram apresentados pelas famílias Chrysobalanaceae, Arecaceae, Fabaceae, Rubiaceae, Lecythidaceae e Burseraceae. Em termos de riqueza de espécies, as famílias mais representativas foram Fabaceae, Arecaceae, Moraceae, Rubiaceae, Melastomataceae e Urticaceae, representando 42% da riqueza local. Os índices de diversidade de Shanon-Weaver (H’ = 3,81) e de similaridade florística calculada pelo índice de Sorensen (variando de 6 a 81%) indicam que a floresta não é muito diversificada, considerando-se o bioma amazônico, mas ainda assim com alta variabilidade da composição de espécies entre as parcelas.Palavras-chave: Fitossociologia, biodiversidade, ESEC Cuniã, PPBio, Amazônia Sul-Ocidental.     

    Balanophoraceae da Estação Ecológica do Cuniã, Porto Velho, RO, Brasil

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    The Balanophoraceae family constitutes as an exclusively angiosperm root holoparasite. It is one of the most representative however it has little expression in Brazilian herbaria. In this context, this study aims to provide data from the floristic inventories carried out in EcologicalCuniã Station (ESEC Cuniã – Porto Velho, RO, Brazil), where stands the Standard Research Program in Biodiversity Grade (PPBio) Cuniã, which has an area of 25 square kilometers, inserted between the interfluves of the Purus – Madeira rivers. Inventories and botanical sampling were made in 48 installments (30 upland and 18 riparian) existing in the study area. It was adopted to sample the range of 2.5 m wide by 250 m long. Balanophoraceae was represented by Helosis genus, with a single species (H. cayennensis), which was recorded in only three of the 48 installments. There were sampled 10 individuals, associated with high humidity environments and sandy soil, as a parasite of the genus Inga L

    RIQUEZA E SELETIVIDADE DE PALMEIRAS AO LONGO DE GRADIENTES AMBIENTAIS NA REGIÃO DO INTERFLÚVIO PURUS-MADEIRA EM PORTO VELHO, RO

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    This study aimed to evaluate environmental gradients influence on richness and selectivity of Palm (Arecaceae) species in a section of Purus-Madeira interfluvial region, Cuniã Ecological Station, in Porto Velho – Rondônia, Brazil. It hás been used RAPELD sampling method. 48 plots were studied in a 25km2 area, being 30 plots in Terra Firme and 18 riparians. It was identified a comunity composed of 49 species distributed in 11 genres. Cluster similarity analysis (Twinspan ordenation method) were used to verify preferential species according to local conditions. Sorensen and Twinspan similarity analysis indicates response from species to soil type variation and water distance, some species occuring only at hidromorphic soils. Results show that site Palms richness and selectivity are determined in part by soil inclination, type and humidity, existing selectivity internal gradients inside and between sampling plots which evidence its strong influence on site palms richness.Keywords: Arecaceae; palms; environmental factors; Amazon; vegetation distribution.O presente trabalho teve como objetivo avaliar a influência de gradientes ambientais sobre a riqueza e seletividade de espécies de Palmeiras (Arecaceae) em um trecho do interflúvio Purus-Madeira na Estação Ecológica do Cuniã em Porto Velho Rondônia. Utilizou-se o método RAPELD de amostragem padrão para estudar 48 parcelas em uma área de 25km2, sendo 30 parcelas em áreas de terra firme e 18 ripárias, sendo identificada uma comunidade composta de 49 espécies distribuídas em 11 gêneros. Foram utilizadas analises de Similaridade de Cluster (Ordenação pelo método de Twinspan), para verificar as espécies preferenciais de acordo com as condições locais.  Análises de similaridade de Sorensen e Twinspan indicam que as espécies respondem às variações do tipo de solo e distância da água, com algumas espécies ocorrendo exclusivamente em solo hidromórficos. Os resultados mostram que a riqueza e seletividade de palmeiras na área são determinadas em parte pela inclinação, tipo e umidade do solo, existindo gradientes internos de seletividade dentro e entre unidades amostrais que evidenciam a forte influência destes gradientes sobre a riqueza de palmeiras na área.Palavras-chave: Arecaceae, palmeiras, fatores ambientais, Amazônia, distribuição vegetal

    AVALIAÇÃO ETNOBOTÂNICA DE PLANTAS UTILIZADAS COMO POTENCIAIS ANTIMALÁRICOS NA REGIÃO DA AMAZÔNIA OCIDENTAL BRASILEIRA

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    O planejamento satisfatório de novos alvos contra os estágios do parasito da malária esbarra nas lacunas sobre o conhecimento de plantas com potencial terapêutico, associadas à desvalorização das informações empíricas e à dispersão destas plantas medicinais arquivadas na memória da população usuária. No presente estudo, foi realizada uma avaliação etnobotânica de plantas com potencial medicinal utilizadas pelos pacientes com a infecção. Os participantes eram residentes de duas localidades da Amazônia ocidental, Porto Velho e Triunfo, entre as regiões urbana e rural. Foram entrevistadas 62 pessoas tidas como informantes, dos quais 62,9% afirmaram que utilizam a terapia natural com potencial medicinal. Foram relatadas 12 plantas pertencentes a 10 famílias: Asteraceae (2 etnoespécies), Rubiaceae (2 etnoespécies), Arecaceae, Lamiacea, Solanaceae, Fabaceae, Cucurbiaceae, Caprifoliaceae, Euphorbiaceae com 1 etnoespécie cada; as espécies mais citadas foram o Plectranthus barbatus Andrews (Boldo) e o Bidens pilosa L. (Picão), sendo as folhas as partes mais utilizadas. Os dados obtidos foram confrontados com a literatura científica reportada nas plataformas: SciELO, PubMed, ScienceDirect e LILACS. Encontramos 131 espécies distribuídas entre 61 famílias de plantas diferentes. As espécies citadas foram Lantana camara L., Phyllanthus amarus Schumach. & Thonn; dentre as famílias, estão a Asteraceae e a Limiaceae, que foram mais bem representadas. A viabilidade na utilização de plantas é um processo economicamente viável e atrativo para as populações desfavorecidas de assistência em saúde, entretanto, requer cuidados e estudos sobre as suas propriedades, a atividade e o desempenho do seu potencial ativo como alvos para a utilização na quimioterapia contra o Plasmodium spp

    Geographic patterns of tree dispersal modes in Amazonia and their ecological correlates

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    Unidad de excelencia María de Maeztu CEX2019-000940-MAim: To investigate the geographic patterns and ecological correlates in the geographic distribution of the most common tree dispersal modes in Amazonia (endozoochory, synzoochory, anemochory and hydrochory). We examined if the proportional abundance of these dispersal modes could be explained by the availability of dispersal agents (disperser-availability hypothesis) and/or the availability of resources for constructing zoochorous fruits (resource-availability hypothesis). Time period: Tree-inventory plots established between 1934 and 2019. Major taxa studied: Trees with a diameter at breast height (DBH) ≥ 9.55 cm. Location: Amazonia, here defined as the lowland rain forests of the Amazon River basin and the Guiana Shield. Methods: We assigned dispersal modes to a total of 5433 species and morphospecies within 1877 tree-inventory plots across terra-firme, seasonally flooded, and permanently flooded forests. We investigated geographic patterns in the proportional abundance of dispersal modes. We performed an abundance-weighted mean pairwise distance (MPD) test and fit generalized linear models (GLMs) to explain the geographic distribution of dispersal modes. Results: Anemochory was significantly, positively associated with mean annual wind speed, and hydrochory was significantly higher in flooded forests. Dispersal modes did not consistently show significant associations with the availability of resources for constructing zoochorous fruits. A lower dissimilarity in dispersal modes, resulting from a higher dominance of endozoochory, occurred in terra-firme forests (excluding podzols) compared to flooded forests. Main conclusions: The disperser-availability hypothesis was well supported for abiotic dispersal modes (anemochory and hydrochory). The availability of resources for constructing zoochorous fruits seems an unlikely explanation for the distribution of dispersal modes in Amazonia. The association between frugivores and the proportional abundance of zoochory requires further research, as tree recruitment not only depends on dispersal vectors but also on conditions that favour or limit seedling recruitment across forest types

    Local hydrological conditions influence tree diversity and composition across the Amazon basin

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    Tree diversity and composition in Amazonia are known to be strongly determined by the water supplied by precipitation. Nevertheless, within the same climatic regime, water availability is modulated by local topography and soil characteristics (hereafter referred to as local hydrological conditions), varying from saturated and poorly drained to well-drained and potentially dry areas. While these conditions may be expected to influence species distribution, the impacts of local hydrological conditions on tree diversity and composition remain poorly understood at the whole Amazon basin scale. Using a dataset of 443 1-ha non-flooded forest plots distributed across the basin, we investigate how local hydrological conditions influence 1) tree alpha diversity, 2) the community-weighted wood density mean (CWM-wd) – a proxy for hydraulic resistance and 3) tree species composition. We find that the effect of local hydrological conditions on tree diversity depends on climate, being more evident in wetter forests, where diversity increases towards locations with well-drained soils. CWM-wd increased towards better drained soils in Southern and Western Amazonia. Tree species composition changed along local soil hydrological gradients in Central-Eastern, Western and Southern Amazonia, and those changes were correlated with changes in the mean wood density of plots. Our results suggest that local hydrological gradients filter species, influencing the diversity and composition of Amazonian forests. Overall, this study shows that the effect of local hydrological conditions is pervasive, extending over wide Amazonian regions, and reinforces the importance of accounting for local topography and hydrology to better understand the likely response and resilience of forests to increased frequency of extreme climate events and rising temperatures

    Estimating the global conservation status of more than 15,000 Amazonian tree species

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    Estimates of extinction risk for Amazonian plant and animal species are rare and not often incorporated into land-use policy and conservation planning. We overlay spatial distribution models with historical and projected deforestation to show that at least 36% and up to 57% of all Amazonian tree species are likely to qualify as globally threatened under International Union for Conservation of Nature (IUCN) Red List criteria. If confirmed, these results would increase the number of threatened plant species on Earth by 22%. We show that the trends observed in Amazonia apply to trees throughout the tropics, and we predict thatmost of the world’s >40,000 tropical tree species now qualify as globally threatened. A gap analysis suggests that existing Amazonian protected areas and indigenous territories will protect viable populations of most threatened species if these areas suffer no further degradation, highlighting the key roles that protected areas, indigenous peoples, and improved governance can play in preventing large-scale extinctions in the tropics in this century

    Estimating the global conservation status of more than 15,000 Amazonian tree species

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    Geography and ecology shape the phylogenetic composition of Amazonian tree communities

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    Aim: Amazonia hosts more tree species from numerous evolutionary lineages, both young and ancient, than any other biogeographic region. Previous studies have shown that tree lineages colonized multiple edaphic environments and dispersed widely across Amazonia, leading to a hypothesis, which we test, that lineages should not be strongly associated with either geographic regions or edaphic forest types. Location: Amazonia. Taxon: Angiosperms (Magnoliids; Monocots; Eudicots). Methods: Data for the abundance of 5082 tree species in 1989 plots were combined with a mega-phylogeny. We applied evolutionary ordination to assess how phylogenetic composition varies across Amazonia. We used variation partitioning and Moran\u27s eigenvector maps (MEM) to test and quantify the separate and joint contributions of spatial and environmental variables to explain the phylogenetic composition of plots. We tested the indicator value of lineages for geographic regions and edaphic forest types and mapped associations onto the phylogeny. Results: In the terra firme and várzea forest types, the phylogenetic composition varies by geographic region, but the igapó and white-sand forest types retain a unique evolutionary signature regardless of region. Overall, we find that soil chemistry, climate and topography explain 24% of the variation in phylogenetic composition, with 79% of that variation being spatially structured (R2^{2} = 19% overall for combined spatial/environmental effects). The phylogenetic composition also shows substantial spatial patterns not related to the environmental variables we quantified (R2^{2} = 28%). A greater number of lineages were significant indicators of geographic regions than forest types. Main Conclusion: Numerous tree lineages, including some ancient ones (>66 Ma), show strong associations with geographic regions and edaphic forest types of Amazonia. This shows that specialization in specific edaphic environments has played a long-standing role in the evolutionary assembly of Amazonian forests. Furthermore, many lineages, even those that have dispersed across Amazonia, dominate within a specific region, likely because of phylogenetically conserved niches for environmental conditions that are prevalent within regions

    Geographic patterns of tree dispersal modes in Amazonia and their ecological correlates

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    Aim: To investigate the geographic patterns and ecological correlates in the geographic distribution of the most common tree dispersal modes in Amazonia (endozoochory, synzoochory, anemochory and hydrochory). We examined if the proportional abundance of these dispersal modes could be explained by the availability of dispersal agents (disperser-availability hypothesis) and/or the availability of resources for constructing zoochorous fruits (resource-availability hypothesis). Time period: Tree-inventory plots established between 1934 and 2019. Major taxa studied: Trees with a diameter at breast height (DBH) ≥ 9.55 cm. Location: Amazonia, here defined as the lowland rain forests of the Amazon River basin and the Guiana Shield. Methods: We assigned dispersal modes to a total of 5433 species and morphospecies within 1877 tree-inventory plots across terra-firme, seasonally flooded, and permanently flooded forests. We investigated geographic patterns in the proportional abundance of dispersal modes. We performed an abundance-weighted mean pairwise distance (MPD) test and fit generalized linear models (GLMs) to explain the geographic distribution of dispersal modes. Results: Anemochory was significantly, positively associated with mean annual wind speed, and hydrochory was significantly higher in flooded forests. Dispersal modes did not consistently show significant associations with the availability of resources for constructing zoochorous fruits. A lower dissimilarity in dispersal modes, resulting from a higher dominance of endozoochory, occurred in terra-firme forests (excluding podzols) compared to flooded forests. Main conclusions: The disperser-availability hypothesis was well supported for abiotic dispersal modes (anemochory and hydrochory). The availability of resources for constructing zoochorous fruits seems an unlikely explanation for the distribution of dispersal modes in Amazonia. The association between frugivores and the proportional abundance of zoochory requires further research, as tree recruitment not only depends on dispersal vectors but also on conditions that favour or limit seedling recruitment across forest types
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