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Biased-corrected richness estimates for the Amazonian tree flora
Full text linkAmazonian forests are extraordinarily diverse, but the estimated species richness is very much debated. Here, we apply an ensemble of parametric estimators and a novel technique that includes conspecific spatial aggregation to an extended database of forest plots with up-to-date taxonomy. We show that the species abundance distribution of Amazonia is best approximated by a logseries with aggregated individuals, where aggregation increases with rarity. By averaging several methods to estimate total richness, we confirm that over 15,000 tree species are expected to occur in Amazonia. We also show that using ten times the number of plots would result in an increase to just ~50% of those 15,000 estimated species. To get a more complete sample of all tree species, rigorous field campaigns may be needed but the number of trees in Amazonia will remain an estimate for years to come. © 2020, The Author(s)
Recursos polínicos coletados por Melipona Illiger, 1806 e Frieseomelitta Ihering, 1912 (Apidae-Apinae-Meliponini) em matas de igapós do Rio Negro, Amazonas, Brasil
Full text linkThere is a great diversity of meliponines in Brazil, especially in the Amazon. These insects have one of the most important functions for the maintenance of life on the planet: pollination. In addition, bees have an economic importance: meliponiculture, a profitable activity that sustains many communities. That is why work on these Meliponines is so important. In 1999, an excursion was made in the Amazon along the Rio Negro channel, led by Dr. João Maria Franco de Camargo and collections of pollen material from various Meliponines were carried out. In this study the pollen resources of 10 species of stingless bees were studied, whose nests were arranged along a 1600km stretch on the banks of the Rio Negro, Amazonas, Brazil. The samples were collected in the end of the rainy season (July-August) in 1999. The material was taken from pollen pots found in natural nests. The pollen material was homogenized and prepared according to the usual acetolysis technique. The work consisted of the identification of pollen types, calculation of the trophic niche overlap between pairs of bee species and cluster analysis of diets. The work was divided into two chapters, the first of which analyzed pollen pots from four species of bees belonging to the genus Frieseomelitta. In the second chapter, samples of six species of Melipona were analyzed. Of the 31 samples obtained from the Frieseomelitta nests, 32 plant species (17 botanical families) were identified, 12 of which were considered attractive to these bees, while six were promoters of temporary specialization events. The results reaffirmed the potentially generalist pattern of these bees with the occurrence of temporary specialization events, being more influenced by local conditions than by the kinship between species in the collection of pollen resources. In the second chapter of the 17 obtained from Melipona nests, 32 plant species (17 botanical families) were identified. Of these, 12 pollen types were considered attractive and each pollen pot, on average, had five pollen types. The species accumulation curve, produced by rarefaction, showed a stabilization of the number of species with the count of 600 grains. Finally, this work indicates important botanical species for crops close to nests of bee species present in this study, either for species conservation programs or Meliponaries.Existe uma grande diversidade de meliponíneos no Brasil, em especial na Amazônia. Esses insetos possuem uma das funções mais importantes para a manutenção da vida no planeta: a polinização. Além disso, as abelhas possuem uma importância econômica: a meliponicultura, uma atividade rentável que sustenta muitas comunidades. Por isso trabalhos a respeito desses Meliponíneos são tão importantes. No ano de 1999, foi realizada uma excussão na Amazônia ao longo do canal do Rio Negro, liderada por pelo Dr. João Maria Franco de Camargo e realizadas coletas de material polínico de vários Meliponíneos. Neste estudo foram estudados os recursos polínicos de 10 espécies de abelhas sem ferrão, cujos os ninhos estavam dispostos ao longo de um trecho 1600km às margens do Rio Negro, Amazonas, Brasil. As amostras foram coletadas no período final da estação chuvosa (julho-agosto) do ano de 1999. O material foi retirado de potes de pólen encontrados em ninhos naturais. O material polínico foi homogeneizado e preparado segundo técnica usual de acetólise. O trabalho consistiu na identificação dos tipos polínicos, cálculo da sobreposição de nicho trófico entre pares de espécies de abelhas e análise de agrupamento das dietas. O trabalho foi dividido em dois capítulos, sendo que no primeiro foram analisados potes de pólen de quatro espécies de abelhas pertencentes ao gênero Frieseomelitta. No segundo capítulo foram analisadas amostras de seis espécies de Melipona. Das 31 amostras obtidas dos ninhos de Frieseomelitta foram identificadas 65 espécies vegetais (29 famílias botânicas), sendo 18 destes, considerados atrativos para essas abelhas, enquanto três foram promotores de eventos de especialização temporária. Os resultados reafirmaram o padrão potencialmente generalistas dessas abelhas com a ocorrência de eventos de especialização temporária, sendo mais influenciado pelas condições locais do que pelo parentesco entre as espécies na coleta dos recursos polínicos. No segundo capítulo das 17 amostras obtidas de ninhos de Melipona, foram identificadas 32 espécies vegetais (17 famílias botânicas). Destas, 13 tipos polínicos foram considerados atrativos e cada pote de pólen, em média, apresentou cinco tipos polínicos. A curva de acumulação de espécies, produzidas por rarefação mostraram estabilização do número de espécies com a contagem de 600 grãos. Por fim, este trabalho sinaliza espécies botânicas importantes para cultivos próximos a ninhos das espécies de abelhas presentes neste estudo, seja para programas de conservação das espécies ou Meliponários
Islands in a green ocean: Spatially structured endemism in Amazonian white-sand vegetation
No full textHere, we examine the influence of the spatial distribution of open white-sand campina (WSC) in the Amazon on the species richness and beta diversity of their vascular plants. It is well known that beta diversity tends to increase with geographical distance, but the influence of habitat insularity on floristic composition and endemism is still unclear. We surveyed WSC in central and southwestern Amazon, generating lists of species occurrences by rapid-inventory techniques to evaluate the influence of island area and connectivity on alpha and beta diversity among five landscapes in the Amazon Basin. Effects of insularity were assessed by comparing alpha and beta diversity within and among landscapes. A high proportion of species (~74%) and genera (~50%) were restricted to only one of the five landscapes and only three species and 28 genera were shared among all landscapes. At the regional scale, beta diversity increased significantly with distance. Partitioning of beta diversity showed that landscapes of higher connectivity have greater turnover and lower nestedness. We conclude that the flora of WSC is highly structured at regional scales, while at the local scale structure is evident only in low connectivity landscapes. Landscape metrics apparently play an important role in shaping patterns of diversity regionally as a result of processes operating at larger geographical scales. This emphasizes that conservation policy should not be local in its geographical focus and should account for connectivity at larger scales. This study is the first to empirically and explicitly evaluate the pattern of endemism in lowland WSC in the Amazon. Abstract in Porteges is available with online only. © 2019 The Association for Tropical Biology and Conservatio
Time of activity is a better predictor of the distribution of a tropical lizard than pure environmental temperatures
No full textEnvironmental temperatures influence ectotherms’ physiology and capacity to perform activities necessary for survival and reproduction. Time available to perform those activities is determined by thermal tolerances and environmental temperatures. Estimates of activity time might enhance our ability to predict suitable areas for species’ persistence in face of climate warming, compared to the exclusive use of environmental temperatures, without considering thermal tolerances. We compare the ability of environmental temperatures and estimates of activity time to predict the geographic distribution of a tropical lizard, Tropidurus torquatus. We compared 105 estimates of activity time, resulting from the combination of four methodological decisions: 1) how to estimate daily environmental temperature variation (modeling a sinusoid wave ranging from monthly minimum to maximum temperature, extrapolating from operative temperatures measured in field or using biophysical projections of microclimate)? 2) In which temperature range are animals considered active? 3) Should these ranges be determined from body temperatures obtained in laboratory or in field? And 4) should thermoregulation simulations be included in estimations? We show that models using estimates of activity time made with the sinusoid and biophysical methods had higher predictive accuracy than those using environmental temperatures alone. Estimates made using the central 90% of temperatures measured in a thermal gradient as the temperature range for activity also ranked higher than environmental temperatures. Thermoregulation simulations did not improve model accuracy. Precipitation ranked higher than thermally related predictors. Activity time adds important information to distribution modeling and should be considered as a predictor in studies of the distribution of ectotherms. The distribution of T. torquatus is restricted by precipitation and by the effect of lower temperatures on their time of activity and climate warming could lead to range expansion. We provide an R package ‘Mapinguari’ with tools to generate spatial predictors based on the processes described herein. © 2020 Nordic Society Oikos. Published by John Wiley & Sons Lt
Morpho-Anatomical and Molecular Characterization of the Oversprouting Symptoms Caused by Fusarium decemcellulare in Guarana Plants (Paullinia cupana var. sorbilis)
No full textOversprouting is a poorly studied disease of guarana plant (Paullinia cupana var. sorbilis), a native species from Amazon Rainforest caused by Fusarium decemcellulare (FDC) that affects the plant growth and reproduction, severely compromising productivity. The sorbilis variety of guarana is anciently cultivated and is used today for the industry of soft drinks, cosmetic and pharmaceutical. Transcriptome, proteome, light and electron microscopy were used to compare symptomatic and asymptomatic tissues and reveal anatomical, histological and cytological alterations resultant from the disease. Disease symptoms described here include a marked reduction in the longitudinal axis and the formation of “capsules”, named as this for the first time here, which display hard thickened external walls and contain extremely malformed floral organs and/or poorly differentiated vegetative primordia when occurring isolate in individual branching points. The aggregate of multiple “capsules” in a same branch point produces galls. The production of indol-acetic acid (IAA) in vitro by F. decemcellulare was for the first time reported and the comparative transcriptome and preliminary proteome data from symptomatic and asymptomatic tissues, support the occurrence of hormonal imbalance identified through several plant hormone-related genes and proteins differentially expressed only in symptomatic tissues. Auxin signaling mechanism, as well as auxin-responsive genes associated to cell cycling, division and proliferation also occurred differentially in infected tissues. Oversprouting and the reduction of the longitudinal axis in malformed cells and organs are related to hormonal unbalance are discussed in this paper. © 2020, Springer Science+Business Media, LLC, part of Springer Nature
Socoró (Mouriri guianensis Aubl.): germinação, desenvolvimento da plântula e classificação das sementes para fins de armazenamento
Full text linkMouriri guianensis is a fruit tree of the family Melastomataceae, which is founded naturally on the bakes of rivers and lakes. Its fruits with a sweet taste, are consumed in natura by human, and above all, by the aquatic fauna. Despite the potential use of this species, information about it is scarce. Thus, it was sought to elucidate some information related to fruit, seeds, germinate and beginning stages of seedling development. This work has been divided into two chapters. The first, intituled Fruit and seed characterization, emergence and development of the seedling of Mouriri guianensis, that presents the results of the characterization of fruits and seeds, of the emergency in function of matrixes and description and identification of the structures in the seedling development. It was found that the fruit is of the bacoideus type, indehiscent, of medium side and round shape. It presents from 1 or 2 seed per fruit. The seeds are brown, small and opaque, with a firm consistency, smooth and polished forehead. The seeds of the different matrixes exhibit significant differences in terms of emergency, with an average emergency time of 80 to 88 days. The germintion is of the bypogeal, cryptocotylar and unipolar type, starting on the 24th day upon sowing with the protrusion of the primary root, followed by the elongation of the epicotyl, appearance of the secondary roots, cataphylls and eophylls, with the seedling showing the second pair of eophylls expanded at 52 days after sowing. The second chapter, titled Classification of the socoró seeds (Mouriri guianensis Aubl.) as regards tolerance to desiccation and storage, aimed at classifying the seeds of Mouriri guianensis as regards tolerance to desiccation, aiming to indicate the most appropriate conditions for maintaining their viability. The Hong and Ellis protocol was adopted for this purpose, with adaptations. Seeds with different degrees of humidity (36.9; 22.3; 10,7; 5.3%), just as a degree of humidity of 5.3%, which after being stored for three months at -18 ºC, were submitted to the emergency test. The socoró seeds have an orthodox behavior, since they can withstand the desiccation until the degree of humidity of 5.3%; the storage, with this water content, for a period of three months, under the temperature of -18 ºC, maintain ed seed viability.
Keywords: Melastomataceae, biometry, seedlings, desiccation, viability.Mouriri guianensis é uma árvore frutífera da família Melastomataceae, encontrada naturalmente às margens dos rios e lagos. Seus frutos, de sabor doce, são consumidos de forma in natura pelo homem e, sobretudo, pela fauna aquática. Apesar do potencial de uso dessa espécie, as informações acerca da mesma são escassas. Assim, buscou-se elucidar algumas informações relacionadas aos frutos, sementes, germinação e estádios iniciais de desenvolvimento da plântula. Para tanto, este trabalho foi dividido em dois capítulos. O primeiro, intitulado Caracterização de frutos e sementes, emergência e desenvolvimento da plântula de Mouriri guianensis, apresenta resultados da caracterização dos frutos e sementes, da emergência em função das matrizes, bem como a descrição e identificação das estruturas no desenvolvimento da plântula. Verificou-se que o fruto é do tipo bacóide, indeiscente, de tamanho médio e formato globoso. Apresenta de 1 a 2 sementes por fruto. As sementes são marrons, pequenas e opacas, de consistência firme, apresentando testa lisa e polida. As sementes das diferentes matrizes apresentam diferenças significativas quanto a emergência, com tempo médio de emergência de 80 a 88 dias. A germinação é do tipo hipógea, criptocotiledonar e unipolar, iniciando-se no vigésimo quarto dia após a semeadura, com a protrusão da raiz primária, seguida do alongamento do epicótilo, aparecimento das raízes secundárias, catafilos e eofilos, e o segundo par de eofilo expandido aos 52 dias após a semeadura. O segundo capítulo, intitulado Classificação das sementes de socoró (Mouriri guianensis Aubl.) quanto a tolerância ao dessecamento e ao armazenamento, teve como objetivo classificar as sementes de Mouriri guianensis quanto à tolerância à dessecação, visando a indicação de condições mais adequadas de conservação da viabilidade das mesmas. Para tanto, foi adotado o protocolo de Hong e Ellis, com adaptações. Sementes com diferentes graus de umidade (36,9; 22,3; 10,7; 5,3%), assim como o grau de umidade de 5,3%, depois de armazenadas por três meses a -18 ºC, foram submetidas ao teste de emergência. As sementes de socoró apresentam comportamento ortodoxo, uma vez que suportam a dessecação até o grau de umidade de 5,3%; o armazenamento, com este teor de água, pelo período de três meses, sob temperatura de -18 ºC, manteve a viabilidade das sementes.
Palavras-chave: Melastomataceae, biometria, plântula, dessecamento, viabilidade
Competition influences tree growth, but not mortality, across environmental gradients in Amazonia and tropical Africa
Full text linkCompetition among trees is an important driver of community structure and dynamics in tropical forests. Neighboring trees may impact an individual tree’s growth rate and probability of mortality, but large-scale geographic and environmental variation in these competitive effects has yet to be evaluated across the tropical forest biome. We quantified effects of competition on tree-level basal area growth and mortality for trees ≥10-cm diameter across 151 ~1-ha plots in mature tropical forests in Amazonia and tropical Africa by developing nonlinear models that accounted for wood density, tree size, and neighborhood crowding. Using these models, we assessed how water availability (i.e., climatic water deficit) and soil fertility influenced the predicted plot-level strength of competition (i.e., the extent to which growth is reduced, or mortality is increased, by competition across all individual trees). On both continents, tree basal area growth decreased with wood density and increased with tree size. Growth decreased with neighborhood crowding, which suggests that competition is important. Tree mortality decreased with wood density and generally increased with tree size, but was apparently unaffected by neighborhood crowding. Across plots, variation in the plot-level strength of competition was most strongly related to plot basal area (i.e., the sum of the basal area of all trees in a plot), with greater reductions in growth occurring in forests with high basal area, but in Amazonia, the strength of competition also varied with plot-level wood density. In Amazonia, the strength of competition increased with water availability because of the greater basal area of wetter forests, but was only weakly related to soil fertility. In Africa, competition was weakly related to soil fertility and invariant across the shorter water availability gradient. Overall, our results suggest that competition influences the structure and dynamics of tropical forests primarily through effects on individual tree growth rather than mortality and that the strength of competition largely depends on environment-mediated variation in basal area. © 2020 The Authors. Ecology published by Wiley Periodicals LLC on behalf of Ecological Society of Americ
Redescription of acropsis grant, 1958 (orthoptera: Tettigoniidae: phaneropterinae: Microcentrini) and description of new species from Brazilian and Colombian amazon rainforest
No full textAcropsis Grant, 1958 is a monotypic genus with records only for Peru (type locality). Acropsis is being redescribed, including the Acropsis tectiformis species and two new species: Acropsis solimoesensis sp. nov. and Acropsis julianae sp. nov. The male internal genitalia and the stridulatory file morphology for the genus is being described for the first time. Furthermore, the genus is registered for the first time for Colombia (Caquetá) and Brazil (Acre and Amazonas) and additionally notes on the habitat are made. Copyright © 2020 Magnolia Press
The role of the Atlantic Multidecadal Oscillation precondition in the teleconnection of different El Niño-Southern Oscillation types and impacts on the 15°N–15°S South American sector precipitation
No full textThe Eastern Pacific (EP) and Central Pacific (CP) El Niño-Southern Oscillation (ENSO) types and their impacts on the tropical North Atlantic (TNA) SST variability and 15°N–15°S South American precipitation during the warm and cold phases of the Atlantic Multidecadal Oscillation (WAMO and CAMO) were evaluated during the 1901–2012 period. The results show more frequent ENSO events during the CAMO. The El Niño (EN) (La Niña [LN]) events, regardless of type (EP or CP), during the WAMO (CAMO) were accompanied by a warming (cooling) in the TNA after its mature phases. In these cases, extratropical teleconnection patterns are established through variations in the Pacific/North America (PNA) teleconnection pattern and are accompanied by variations in the Walker circulation. For the EN (LN) in the CAMO (WAMO), the tropical teleconnections occur predominant, through the Walker cell and the zonal inter-basin gradient, which is intensified due to the SST gradient between the eastern equatorial Pacific (non-neutral anomalies) and the equatorial Atlantic (neutral anomalies). These circulation pattern changes affect the precipitation patterns in the 15°N–15°S South American sector during December–January–February (D(0)JF(+1)) and March–April–May (MAM(+1)). The EP EN (EPEN) events are associated with the intensification of the negative precipitation anomalies in northeastern Brazil (NEB) during the WAMO and in the central part of the Amazon during the CAMO. In the case of CP EN (CPEN) events, the greatest differences between the AMO phases occur during MAM(+1), with reverse sign anomalies over northwestern South America. In the case of LN events, the largest differences occur in NEB, with reduced rainfall in the WAMO, regardless of type EP or CP. The results presented here highlight the role of low frequency oscillations in defining the teleconnection patterns between tropical Pacific and Atlantic Oceans, not discussed previously. © 2019 Royal Meteorological Societ