21 research outputs found

    Pervasive gaps in Amazonian ecological research

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    Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio

    Pervasive gaps in Amazonian ecological research

    Get PDF

    Pervasive gaps in Amazonian ecological research

    Get PDF
    Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost

    Updated cardiovascular prevention guideline of the Brazilian Society of Cardiology: 2019

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    Soil fauna as an indicator of soil quality in forest stands, pasture and secondary forest

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    The interactions between soil invertebrates and environmental variations are relatively unknown in the assessment of soil quality. The objective of this study was to evaluate soil quality in areas with different soil management systems, based on soil fauna as indicator, in Além Paraíba, Minas Gerais, Brazil. The soil invertebrate community was sampled using pitfall traps, in the dry and rainy seasons, from areas with five vegetation types (acacia, mimosa, eucalyptus, pasture, and secondary forest). The abundance of organisms and the total and average richness, Shannon's diversity index, the Pielou uniformity index, and change index V were determined. The fauna was most abundant in the areas of secondary forest and mimosa plantations in the dry season (111.3 and 31.7 individuals per trap per day, respectively). In the rainy season, the abundance of organisms in the three vegetation types did not differ. The highest values of average and total richness were recorded in the secondary forest in the dry season and in the mimosa stand in the rainy season. Shannon's index ranged from 1.57 in areas with acacia and eucalyptus in the rainy season to 3.19 in the eucalyptus area in the dry season. The uniformity index was highest in forest stands (eucalyptus, acacia and mimosa) in the dry season, but higher in the rainy season in the pasture and secondary forest than in the forest stands. The change index V indicated that the percentage of extremely inhibited groups was lowest in the area with mimosa, both in the dry and rainy season (36 and 23 %, respectively). Of all forest stands, the mimosa area had the most abundant soil fauna

    Marandu palisade grass intercropped with densely spaced teak in silvopastoral system

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    Este trabalho foi realizado para avaliar dois sistemas de produção: integração entre teca e forragem (silvipastoril) e somente forragem (monocultivo). A forrageira utilizada foi o capim-Marandu. Em janeiro de 2009, parte do pasto foi dessecado e implantou-se Teca (Tectona grandis) em espaçamento de 3 x 4 m e a cada cinco linhas estabeleceu-se um espaçamento de 6 m entre linhas, o que garantiu uma população de 750 árvores por hectare. Paralelamente ao desenvolvimento das árvores houve o restabelecimento do pasto de capim-Marandu. Em fevereiro de 2015, retirou-se os animais da área e em março avaliou-se o estádio de degradação do pasto, a densidade e a massa de perfilhos. Avaliou-se também a altura do dossel forrageiro, a massa de forragem e as porcentagens de: lâmina foliar, colmo+bainha e material morto, a relação lâmina foliar/colmo+bainha e a relação vivo/não vivo. O delineamento experimental foi inteiramente casualizado, com dois tratamentos (silvipastoril e monocultivo) e doze repetições. A massa de forragem foi maior no sistema com monocultivo de capim-Marandu. A altura da forragem e a porcentagem de colmo + bainha foram maiores no sistema silvipastoril, já a porcentagem de lâmina foliar e a relação lâmina:colmo+bainha foram maiores para o sistema com monocultivo. Conclui-se que o capim-marandu tolera o sombreamento em sistema silvipastoril adensado, contudo o processo de degradação é mais intenso do que o capim em monocultivo e a utilização do capim-Marandu em sistemas silvipastoris altera a massa de forragem e a estrutura da forragem produzida.This study was conducted to evaluate two systems of production: integration between teak and forage (silvopastoral system) and forage only (monoculture). The forage species used was Marandu palisade grass (Urochloa brizantha cv. Marandu). In January 2009, part of the pasture was desiccated and the teak (Tectona grandis) was implemented in a 3 × 4 m spacing arrangement, and at every five rows, a space between rows of 6 m was established, providing a population of 750 trees per hectare. Alongside the development of the trees, the Marandu palisade grass pasture was reestablished. In February 2015, the animals were removed from the experimental area and, in March, the pasture degradation, the density and the mass of tillers was assessed. The following variables were evaluated: sward height; forage mass, percentage of leaf blade, stem+sheath and senescent material; leaf blade:stem+sheath ratio; and live:dead material ratio. The experimental design was completely randomized, with 12 replicates. Treatments consisted of two systems (silvopastoral and monoculture). The total forage accumulation was higher in the monoculture system. The sward height and the percentage of stem+sheath were higher in the integrated system, while the percentage of leaf blade and the leaf blade:stem+sheath ratio were higher in the system exclusively with forage. In conclusion, Marandu palisade grass tolerates shading in a high density spacing silvopastoral system, but the degradation process is more intense compared to grass in monoculture, and the use of Marandu palisade grass in silvopastoral systems changes the forage mass and the structure of the produced forage
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