Floristic inventory of three hectares of "Terra firme" forest in the petroleum drilling region of the Urucu River in the Amazon state, Brazil

The aim of this paper is to characterize forest vegetation in the Urucu River region, a petroleum drilling area of PETROBRAS. This information may contribute to the organized and productive use of the forest, based on scientific knowledge, so that economic returns can be obtained while conserving the environment. All tree, vine and palm stems over 10 cm DBH were inventoried in three hectares. A total of 2241 individuals were found in 60 families, 225 genera and 577 species or morphospecies. Three measures of ecological importance - abundance, dominance and frequency - expressed as three separate percentages were summed to give an Importance Value Index (IVIE). The two highest IVI were for Eschweilera coracea (DC.) S. A. Mori, with 15% in hectare 2, and E. wachenheimii (Benoist) Sandwith, with 14% in hectare 3. The highest Family Importance Indices averaged across the three hectares were for Lecythidaceae (51.62%), Sapotaceae (40.24%) and Chrysobalanacaeae (24.56%).O presente trabalho teve por objetivo principal caracterizar a vegetação da área de exploração de petróleo da PETROBRAS, no rio Urucu, bem como dar subsídios para a utilização da floresta de forma organizada e produtiva, baseada em conhecimentos científicos, de modo não somente a produzir resultados econômicos mas principalmente conservar o ambiente. Os três hectares de floresta inventariada sustentam 2.241 indivíduos, abrangendo árvores, palmeiras e cipós com DAP> 10 cm, distribuídos em 577 espécies, 225 gêneros e 60 famílias. Três medidas de importância ecológica - abundância, dominância e frequência - expressas como três porcentagens, foram somadas para obter um índice de Valor de Importância (IVI). As duas espécies com os maiores IV1E, em toda a área pesquisada, foram Eschweilera coriacea (DC.) S. A. Mori, com 15% no hectare 2 e E. wachenheimii (Benoist) Sandwith, com 14% no hectare 3. As famílias que obtiveram os maiores índices de Valor de Importância (IVIF), em média, nos 3 hectares, foram Lecythidaceae (51,6%), Sapotaceae (40,2%) e Chrysobalanaceae (24,6%)

VENENO DA Bothrops jararacussu: DA TOXICIDADE AO POTENCIAL FARMACOLÓGICO

A Jararacuçu (Bothrops jararacussu) é uma víbora bastante venenosa e perigosa, sendo a 2ª maior serpente peçonhenta do Brasil. O presente estudo tem como objetivo, realizar uma revisão sistemática sobre o mecanismo tóxico, manifestações clínicas e o potencial farmacológico do veneno da Bothrops jararacussu. Trata-se de um estudo de caráter descritivo, de revisão sistemática. Realizado no período de março a maio de 2022, utilizando-se as bases de dados SCIELO e PUBMED. As palavras chaves para busca foram: Bothrops jararacussu e jararacuçu. Incluídos artigos publicados em 2018 a 2022, nos idiomas português e inglês e excluídos artigos repetidos, preprint e que não tinham correlação. Após a seleção dos artigos as informações foram organizadas em tabelas. No presente estudo foram incluídos 14 artigos. Os artigos demonstram potenciais farmacológicos de substâncias isoladas do veneno da B. jararacussu. O veneno de serpentes envolve uma complexa mistura de substâncias orgânicas e inorgânicas. Nas espécies de jararacas, especificamente, tem-se mais de 20 peptídeos e proteínas farmacologicamente ativos e envolvidos nos sintomas tóxicos de acidentes com esses animais. Em estudos foram observadas atividades farmacológicas das substâncias isoladas do veneno da B. jararacussu. Concluímos que substâncias presentes no veneno da espécie Bothrops jararacussu apresentam potencial farmacológico para o tratamento de diversas doenças, entre elas, alguns tipos celulares de cânceres, atividade antileishmania, antimicrobiana e candidata ao tratamento para o combate a COVID-19

One sixth of Amazonian tree diversity is dependent on river floodplains

Amazonia’s floodplain system is the largest and most biodiverse on Earth. Although forests are crucial to the ecological integrity of floodplains, our understanding of their species composition and how this may differ from surrounding forest types is still far too limited, particularly as changing inundation regimes begin to reshape floodplain tree communities and the critical ecosystem functions they underpin. Here we address this gap by taking a spatially explicit look at Amazonia-wide patterns of tree-species turnover and ecological specialization of the region’s floodplain forests. We show that the majority of Amazonian tree species can inhabit floodplains, and about a sixth of Amazonian tree diversity is ecologically specialized on floodplains. The degree of specialization in floodplain communities is driven by regional flood patterns, with the most compositionally differentiated floodplain forests located centrally within the fluvial network and contingent on the most extraordinary flood magnitudes regionally. Our results provide a spatially explicit view of ecological specialization of floodplain forest communities and expose the need for whole-basin hydrological integrity to protect the Amazon’s tree diversity and its function

The biogeography of the Amazonian tree flora

We describe the geographical variation in tree species composition across Amazonian forests and show how environmental conditions are associated with species turnover. Our analyses are based on 2023 forest inventory plots (1 ha) that provide abundance data for a total of 5188 tree species. Within-plot species composition reflected both local environmental conditions (especially soil nutrients and hydrology) and geographical regions. A broader-scale view of species turnover was obtained by interpolating the relative tree species abundances over Amazonia into 47,441 0.1-degree grid cells. Two main dimensions of spatial change in tree species composition were identified. The first was a gradient between western Amazonia at the Andean forelands (with young geology and relatively nutrient-rich soils) and central–eastern Amazonia associated with the Guiana and Brazilian Shields (with more ancient geology and poor soils). The second gradient was between the wet forests of the northwest and the drier forests in southern Amazonia. Isolines linking cells of similar composition crossed major Amazonian rivers, suggesting that tree species distributions are not limited by rivers. Even though some areas of relatively sharp species turnover were identified, mostly the tree species composition changed gradually over large extents, which does not support delimiting clear discrete biogeographic regions within Amazonia

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

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

Geography and ecology shape the phylogenetic composition of Amazonian tree communities

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 (R$^{2}$ = 19% overall for combined spatial/environmental effects). The phylogenetic composition also shows substantial spatial patterns not related to the environmental variables we quantified (R$^{2}$ = 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

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

Geography and ecology shape the phylogenetic composition of Amazonian tree communities

AimAmazonia 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.LocationAmazonia.TaxonAngiosperms (Magnoliids; Monocots; Eudicots).MethodsData 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's 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.ResultsIn 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 = 19% overall for combined spatial/environmental effects). The phylogenetic composition also shows substantial spatial patterns not related to the environmental variables we quantified (R2 = 28%). A greater number of lineages were significant indicators of geographic regions than forest types.Main ConclusionNumerous 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

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

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

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

Para investigar los patrones geográficos y las correlaciones ecológicas en la distribución geográfica de los modos de dispersión arbórea más comunes en la Amazonia (endozoocoria, sinzoocoria, anemoocoria e hidrocoria). Se examina si la abundancia proporcional de estos modos de dispersión podría explicarse por la disponibilidad de agentes dispersores (hipótesis de disponibilidad de dispersores) y/o la disponibilidad de recursos para la producción de frutos zoocoros (hipótesis de disponibilidad de recursos). Se utilizaron parcelas de inventario de árboles establecidas entre 1934 y 2019. Los principales taxones estudiados fueron árboles con un diámetro a la altura del pecho (DAP) ≥ 9,55 cm. Se asignaron modos de dispersión a un total de 5433 especies y morfoespecies en 1877 parcelas de inventario de árboles en bosques de abeto, inundados estacionalmente y permanentemente inundados. Se investigaron los patrones geográficos en la abundancia proporcional de los modos de dispersión. Se realizó una prueba de distancia media entre pares ponderada por abundancia (MPD) y ajustamos modelos lineales generalizados (GLM) para explicar la distribución geográfica de los modos de dispersión. La anemocoria se asoció significativa y positivamente con la velocidad media anual del viento, y la hidrocoria fue significativamente mayor en los bosques inundados. Los modos de dispersión no mostraron consistentemente asociaciones significativas con la disponibilidad de recursos para la construcción de frutos zoocoros. Una menor disimilitud en los modos de dispersión, resultante de una mayor dominancia de la endozoocoria, se produjo en los bosques de abeto (excluyendo los podzoles) en comparación con los bosques inundados. La hipótesis dispersor-disponibilidad fue bien apoyada para los modos de dispersión abióticos (anemochoria e hidrochoria). La disponibilidad de recursos para la construcción de frutos zoochorios parece una explicación poco probable para la distribución de los modos de dispersión en la Amazonia. La asociación entre los frugívoros y la abundancia proporcional de zoocoría requiere más investigación, ya que el crecimiento de árboles no sólo depende de los vectores de dispersión, sino también de las condiciones que favorecen o limitan el crecimiento de plántulas en los distintos tipos de bosque.Revisión por pares