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The Central Amazon Biomass Sink Under Current and Future Atmospheric CO2: Predictions From Big-Leaf and Demographic Vegetation Models
Full text linkThere is large uncertainty whether Amazon forests will remain a carbon sink as atmospheric CO2 increases. Hence, we simulated an old-growth tropical forest using six versions of four terrestrial models differing in scale of vegetation structure and representation of biogeochemical (BGC) cycling, all driven with CO2 forcing from the preindustrial period to 2100. The models were benchmarked against tree inventory and eddy covariance data from a Brazilian site for present-day predictions. All models predicted positive vegetation growth that outpaced mortality, leading to continual increases in present-day biomass accumulation. Notably, the two vegetation demographic models (VDMs) (ED2 and ELM-FATES) always predicted positive stem diameter growth in all size classes. The field data, however, indicated that a quarter of canopy trees didn't grow over the 15-year period, and while high interannual variation existed, biomass change was near neutral. With a doubling of CO2, three of the four models predicted an appreciable biomass sink (0.77 to 1.24 Mg ha−1 year−1). ELMv1-ECA, the only model used here that includes phosphorus constraints, predicted the lowest biomass sink relative to initial biomass stocks (+21%), lower than the other BGC model, CLM5 (+48%). Models projections differed primarily through variations in nutrient constraints, then carbon allocation, initial biomass, and density-dependent mortality. The VDM's performance was similar or better than the BGC models run in carbon-only mode, suggesting that nutrient competition in VDMs will improve predictions. We demonstrate that VDMs are comparable to nondemographic (i.e., “big-leaf”) models but also include finer scale demography and competition that can be evaluated against field observations. ©2020. The Authors
Both near-surface and satellite remote sensing confirm drought legacy effect on tropical forest leaf phenology after 2015/2016 ENSO drought
No full textAmazon forest leaf phenology patterns have often been inferred from the Moderate Resolution Imaging Spectroradiometer (MODIS) Enhanced Vegetation Index (EVI). But reliable MODIS detection of seasonal and interannual leaf phenology patterns has also been questioned and is generally not validated with field observation. Here we compare inter-annual patterns of local-scale upper canopy leaf phenology and demography derived from tower-mounted phenocams at two upland forest sites in the Central Amazon, to corresponding satellite vegetation indices retrieved from MODIS-MAIAC (Multi-Angle Implementation of Atmospheric Correction). We focus on forest response to an unprecedented drought caused by the El Niño of 2015-16. At both sites, multi-year phenocam data showed post-drought shifts in leaf demography. These were consistent with MODIS-MAIAC anomalies in two vegetation indices. Specifically, a precocious leaf flush at both sites during the first two post-drought months, Feb-Mar 2016, caused (1) an anomalous decrease in flushing trees in Jun–Jul of 2016 and (2) an increase of trees with early mature stage leaves (2-4 mo age) in Apr-May-Jun of 2016. At both sites, these two phenological anomalies showed up in MODIS-MAIAC as, respectively, (1) a strong negative anomaly in Gcc (Green chromatic coordinate), which prior work has shown to be sensitive to the abundance of leaves 0-1 mo old, and (2) a strong positive anomaly in EVI, which is sensitive to abundance of leaves 2-4 mo age. A shift to sub-optimal seasonal leaf age mix is expected to change the ecosystem-scale intrinsic photosynthetic capacity for ~18 month after the drought. © 2019 Elsevier Inc
Redescription of ancistrus greeni (Siluriformes: Loricariidae), and description of a new species from the río madre de dios basin, peru
No full textA new species of Ancistrus is described from minor tributaries of the río Madre de Dios basin (Cusco-Madre de Dios-Puno), in Peru. The new species shares with A. greeni an uncommon unicusp dentition; but it is distinguished from A. greeni by a larger orbital diameter, deeper caudal peduncle, and larger adipose-fin spine. The redescription of A. greeni is provided, and its recognition along with the discovery of this new species increases to five the officially number of Ancistrus species from the río Madre de Dios basin. The lectotype and paralectotype of A. greeni are provided. © 2020 The Authors. Diversity and Distributions Published by SBI
Assessing the potential of environmental DNA metabarcoding for monitoring Neotropical mammals: a case study in the Amazon and Atlantic Forest, Brazil
No full textThe application of environmental DNA (eDNA) metabarcoding as a biomonitoring tool has greatly increased, but studies have focused on temperate aquatic macro-organisms. We apply eDNA metabarcoding to detecting the mammalian community in two high-biodiversity regions of Brazil: the Amazon and Atlantic Forests. We identified Critically Endangered and Endangered mammalian species and found overlap with species identified via camera trapping. We highlight the potential for using eDNA monitoring for mammals in biodiverse regions and identify challenges: we need a better understanding of the ecology of eDNA within variable environments and more appropriate reference sequences for species identification in these anthropogenically impacted biomes. © 2020 The Mammal Society and John Wiley & Sons Lt
Diagnóstico da Produção de Sementes e Mudas no Estado do Amazonas
Full text linkThe global environmental policy scenario and Brazil’s commitment to restore extensive areas increases the concern about provision of material for implementation of these projects. To understand the situation of the production of seeds and seedlings in Amazonas state, we did a survey of producers in the state with visits to places of production and application of form. The data obtained were analyzed based on descriptive statistics. Seed and seedling production in the state of Amazonas is still incipient compared to provisioning need for restoration commitments in Brazil. To this end, a data base updated and consistent is required, that could stem from Renasem’s record information. The quantity produced is not yet sufficient to re-establish floral richness of the Amazon. A shift to focus on production native species with restoration potential will be needed for this to be the major destinations of planting material. Thus, economic, production-related sector of seed and seedling needs to be extended, however seems to depend on external incentives for operation, specially regarding financial performance.O cenário global político ambiental e o comprometimento do Brasil em restaurar extensas áreas aumenta a preocupação com o fornecimento de materiais para implementação desses projetos. Para conhecer a situação da produção de sementes e mudas no Amazonas, fizemos um levantamento dos produtores do estado com visitas aos locais de produção e aplicação de formulário. Os dados obtidos foram analisados a partir de estatística descritiva. A produção de sementes e mudas no estado do Amazonas ainda é incipiente quando comparada com a necessidade de provisionamento para compromissos de restauração assumidos pelo Brasil. Para atingir essa finalidade, uma base de dados atualizada e consistente se torna necessária, que pode se originar de informações do Renasem. A quantidade produzida ainda não é significativa, porém pode ser aumentada usando a mesma infraestrutura e número de produtores. Uma mudança do enfoque de produção de espécies nativas com potencial de restauração será necessária para que seja essa a principal destinação do material de plantio. Dessa maneira, o setor econômico produtivo de sementes e mudas precisa ser expandido, porém ainda depende de incentivos externos para operação, principalmente no quesito financeiro
Quantification of bergenin, antioxidant activity and nitric oxide inhibition from bark, leaf and twig of endopleura uchi
No full textDetecção e distribuição temporal de espécies de peixes em lagos de várzea na Amazônia central utilizando dna ambiental (DNAa)
Full text linkThe fish community in four floodplain lakes located on the island of Paciência, Iranduba, in the state of Amazonas, was studied for its detection and temporal distribution using the pioneer method in the Amazon, called environmental DNA (DNAe). The pre-amplification methodology was developed by testing dilutions of DNag, then primers and species-specific probes were designed and synthesized for two target species: Prochilodus nigricans and Potamorhina altamazonica, and primers for Triportheus angulatus and Psectrogaster rutiloides. All primers were tested in silico, in vitro and in situ and validated, with this the presence or absence of the target species was detected and with the metabarcode approach the presence of other fish species, in addition to other organisms, present in the lakes in the dry and flood periods.Estudou-se a comunidade de peixes em quatro lagos de várzea localizados na ilha da Paciência, Iranduba, no estado do Amazonas, quanto a sua detecção e distribuição temporal utilizando o método pioneiro na Amazônia, chamado DNA ambiental (DNAa) – Environmental DNA (DNAe). Foi desenvolvido a metodologia de pré-amplificação testando diluições de DNag, em seguida foi desenhado e sintetizado primers e sondas espécie-específicos para duas espécies alvos: Prochilodus nigricans e Potamorhina altamazonica, e primers para Triportheus angulatus e Psectrogaster rutiloides. Todos os primers foram testados in silico, in vitro e in situ e validados, com isso foi detectada a presença ou ausência das espécies alvos e com a abordagem de metabarcode foi detectado a presença de outras espécies de peixes, além de outros organismos, presentes nos lagos nos período de seca e cheia
Infection and behavior manipulation of social wasps (Vespidae: Polistinae) by Ophiocordyceps humbertii in Neotropical forests: new records of wasp-zombification by a fungus
No full textOphiocordyceps is a genus comprised by entomopathogenic fungi known to infect ten orders of insects, including Hymenoptera. Amongst the nearly 250 species described in the genus, few are known to manipulate their hosts, which are most notably ants. These species cause their hosts to die in an exposed position high above the ground while grabbing and/or biting the abaxial surface of leaves or branches, which in turn optimizes the fungus spore production and dispersal. Herein, we report on 14 social wasp species belonging to four genera (Agelaia, Mischocyttarus Polybia, and Pseudopolybia) infected by Ophiocordyceps humbertii, a common wasp pathogen. This study broadens the geographic and host range for O. humbertii and provides the first record of its ability to manipulate its host. © 2019, © 2019 Informa UK Limited, trading as Taylor & Francis Group
