33 research outputs found

    FITOSSOCIOLOGIA DE UMA FLORESTA DE TERRA FIRME NA AMAZ√ĒNIA SUL-OCIDENTAL, ROND√ĒNIA, 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‚Äôs grid, considering trees DBH ‚Č• 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‚Äô = 3.81) and Sorensen floristic similarity (6-81%) √≠ndices 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 Cuni√£; PPBio; Southwestern Amazon.Este artigo reporta a flor√≠stica e fitossociologia de 30 parcelas de 1 ha em uma floresta de Terra Firme na Amaz√īnia Sul-Ocidental, inseridos em uma grade PPBio de 25km¬≤ e considerando-se indiv√≠duos de DAP ‚Č• 1cm. Foram registrados 10679 indiv√≠duos, sendo 89,1% √°rvores e 10,9% palmeiras, referentes a 196 t√°xons, dos quais 176 foram identificados em n√≠vel espec√≠fico, distribu√≠dos em 47 fam√≠lias e 136 g√™neros. Quanto ao √ćndice de Valor de Import√Ęncia Familiar (IVIF), os maiores valores foram apresentados pelas fam√≠lias Chrysobalanaceae, Arecaceae, Fabaceae, Rubiaceae, Lecythidaceae e Burseraceae. Em termos de riqueza de esp√©cies, as fam√≠lias mais representativas foram Fabaceae, Arecaceae, Moraceae, Rubiaceae, Melastomataceae e Urticaceae, representando 42% da riqueza local. Os √≠ndices de diversidade de Shanon-Weaver (H‚Äô = 3,81) e de similaridade flor√≠stica calculada pelo √≠ndice de Sorensen (variando de 6 a 81%) indicam que a floresta n√£o √© muito diversificada, considerando-se o bioma amaz√īnico, mas ainda assim com alta variabilidade da composi√ß√£o de esp√©cies entre as parcelas.Palavras-chave: Fitossociologia, biodiversidade, ESEC Cuni√£, PPBio, Amaz√īnia 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 EcologicalCuni√£ Station (ESEC Cuni√£ ‚Äď Porto Velho, RO, Brazil), where stands the Standard Research¬†Program in Biodiversity Grade (PPBio) Cuni√£, which has an area of 25 square kilometers,¬†inserted between the interfluves of the Purus ‚Äď 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, Cuni√£ Ecological Station, in Porto Velho ‚Äď Rond√īnia, Brazil. It h√°s 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 influ√™ncia de gradientes ambientais sobre a riqueza e seletividade de esp√©cies de Palmeiras (Arecaceae) em um trecho do interfl√ļvio Purus-Madeira na Esta√ß√£o Ecol√≥gica do Cuni√£ em Porto Velho Rond√īnia. Utilizou-se o m√©todo RAPELD de amostragem padr√£o para estudar 48 parcelas em uma √°rea de 25km2, sendo 30 parcelas em √°reas de terra firme e 18 rip√°rias, sendo identificada uma comunidade composta de 49 esp√©cies distribu√≠das em 11 g√™neros. Foram utilizadas analises de Similaridade de Cluster (Ordena√ß√£o pelo m√©todo de Twinspan), para verificar as esp√©cies preferenciais de acordo com as condi√ß√Ķes locais.¬† An√°lises de similaridade de Sorensen e Twinspan indicam que as esp√©cies respondem √†s varia√ß√Ķes do tipo de solo e dist√Ęncia da √°gua, com algumas esp√©cies ocorrendo exclusivamente em solo hidrom√≥rficos. Os resultados mostram que a riqueza e seletividade de palmeiras na √°rea s√£o determinadas em parte pela inclina√ß√£o, tipo e umidade do solo, existindo gradientes internos de seletividade dentro e entre unidades amostrais que evidenciam a forte influ√™ncia destes gradientes sobre a riqueza de palmeiras na √°rea.Palavras-chave: Arecaceae, palmeiras, fatores ambientais, Amaz√īnia, distribui√ß√£o vegetal

    AVALIA√á√ÉO ETNOBOT√āNICA DE PLANTAS UTILIZADAS COMO POTENCIAIS ANTIMAL√ĀRICOS NA REGI√ÉO DA AMAZ√ĒNIA OCIDENTAL BRASILEIRA

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    O planejamento satisfat√≥rio de novos alvos contra os est√°gios do parasito da mal√°ria esbarra nas lacunas sobre o conhecimento de plantas com potencial terap√™utico, associadas √† desvaloriza√ß√£o das informa√ß√Ķes emp√≠ricas e √† dispers√£o destas plantas medicinais arquivadas na mem√≥ria da popula√ß√£o usu√°ria. No presente estudo, foi realizada uma avalia√ß√£o etnobot√Ęnica de plantas com potencial medicinal utilizadas pelos pacientes com a infec√ß√£o. Os participantes eram residentes de duas localidades da Amaz√īnia ocidental, Porto Velho e Triunfo, entre as regi√Ķes 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 fam√≠lias: Asteraceae (2 etnoesp√©cies), Rubiaceae (2 etnoesp√©cies), Arecaceae, Lamiacea, Solanaceae, Fabaceae, Cucurbiaceae, Caprifoliaceae, Euphorbiaceae com 1 etnoesp√©cie cada; as esp√©cies mais citadas foram o Plectranthus barbatus Andrews (Boldo) e o Bidens pilosa L. (Pic√£o), sendo as folhas as partes mais utilizadas. Os dados obtidos foram confrontados com a literatura cient√≠fica reportada nas plataformas: SciELO, PubMed, ScienceDirect e LILACS. Encontramos 131 esp√©cies distribu√≠das entre 61 fam√≠lias de plantas diferentes. As esp√©cies citadas foram Lantana camara L., Phyllanthus amarus Schumach. & Thonn; dentre as fam√≠lias, est√£o a Asteraceae e a Limiaceae, que foram mais bem representadas. A viabilidade na utiliza√ß√£o de plantas √© um processo economicamente vi√°vel e atrativo para as popula√ß√Ķes desfavorecidas de assist√™ncia em sa√ļde, entretanto, requer cuidados e estudos sobre as suas propriedades, a atividade e o desempenho do seu potencial ativo como alvos para a utiliza√ß√£o 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 Mar√≠a 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) ‚Č• 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) ‚Äď 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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    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) ‚Č•‚ÄČ9.55‚ÄČcm. 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

    Mapping density, diversity and species-richness of the Amazon tree flora

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    Using 2.046 botanically-inventoried tree plots across the largest tropical forest on Earth, we mapped tree species-diversity and tree species-richness at 0.1-degree resolution, and investigated drivers for diversity and richness. Using only location, stratified by forest type, as predictor, our spatial model, to the best of our knowledge, provides the most accurate map of tree diversity in Amazonia to date, explaining approximately 70% of the tree diversity and species-richness. Large soil-forest combinations determine a significant percentage of the variation in tree species-richness and tree alpha-diversity in Amazonian forest-plots. We suggest that the size and fragmentation of these systems drive their large-scale diversity patterns and hence local diversity. A model not using location but cumulative water deficit, tree density, and temperature seasonality explains 47% of the tree species-richness in the terra-firme forest in Amazonia. Over large areas across Amazonia, residuals of this relationship are small and poorly spatially structured, suggesting that much of the residual variation may be local. The Guyana Shield area has consistently negative residuals, showing that this area has lower tree species-richness than expected by our models. We provide extensive plot meta-data, including tree density, tree alpha-diversity and tree species-richness results and gridded maps at 0.1-degree resolution
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