Pervasive gaps in Amazonian ecological research

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

Desempenho ponderal de novilhas mestiças Holandês × Zebu submetidas a duas estratégias de suplementação mineral Ponderal performance of crossbred Holstein × Zebu heifers submitted to two mineral supplementations strategies

Avaliou-se o desempenho ponderal de novilhas em regime de pastejo rotacionado consumindo dois tipos de suplemento mineral. Utilizaram-se 25 novilhas Holandês &times; Zebu, 9 como animais reguladores e 16 como animais-prova, divididas em quatro tratamentos: capim-mombaça e sal seletivo (MSS); capim-mombaça e sal comercial (MSC); capim-elefante e sal seletivo (ESS); e capim-elefante e sal comercial (ESC). O ganho médio diário (GMD) foi calculado pesando-se os animais-prova a cada 28 dias após jejum alimentar de 16 horas. Foram avaliados os consumos de matéria seca de lâmina foliar verde (CMSLFV) e a digestibilidade aparente da matéria seca de lâmina foliar verde (DMSLFV) utilizando-se óxido crômico como marcador externo e fibra em detergente neutro indigerível como marcador interno. Foram mensurados os consumos dos suplementos minerais e avaliados os teores de matéria seca, proteína bruta, fibra em detergente neutro e de Ca, P, K, Mg, Na, Cu, Zn, Fe e Mn somente em amostras de lâmina foliar. O delineamento estatístico utilizado foi o inteiramente casualizado em esquema fatorial 2 &times; 2 (gramínea e mistura mineral). Cada tratamento foi composto por quatro animais, de modo que cada animal constituiu uma unidade experimental. Apenas os minerais Cu, Na e Zn foram encontrados em quantidades insuficientes nas forrageiras. Os CMSLFV não foram influenciados por nenhuma das variáveis estudadas nem por suas interações. Houve interação sal mineral &times; gramínea para a DMSLFV. O GMD foi influenciado apenas pelas gramíneas; o desempenho dos animais que consumiram o capim-elefante foi superior. A composição nutricional do capim-elefante foi ligeiramente superior à do capim-mombaça, o que provavelmente proporcionou melhor desempenho aos animais deste tratamento.<br>The ponderal performance of heifers under rotational grazing fed two types mineral supplement was evaluated. A total of 25 heifers Holstein &times; Zebu, including nine regulator animals and 16 test animals, was divided into four treatments: mombaçagrass (Panicum maximum, CV. Mombaça) with selective salt (MSS), mombaçagrass with commercial salt (MSC), elephantgrass (Pennisetum purpureum, CV. Napier) with selective salt (ESS) and elephantgrass with commercial salt (ESC). Average daily live weight gain (DWG) was calculated by weighing the test animal every 28 days after fasting of 16 hours. Dry matter intake (CMSLFV) and apparent digestibility (DMSLFV) of green leaf blade were evaluated with chromium oxide and indigestible neutral detergent fiber, as external and internal markers, respectively. Mineral supplement intake was measured and the levels of dry matter, crude protein, and of Ca. P, K, Mg, Na, Cu, Zn, Fe and Mn only in grass leaves samples. A completely randomized design in 2 &times; 2 factorial arrangement (grass and mineral mix), was used. Each treatment was composed by four animals, and each animal as considered a experimental unit. Only Cu, Na and Zn were deficient in the forages. The CMSLFV were not affected by the studied variables and no significant interactions were observed. There was interaction between salt mix and grass for DMSLF. The DWG was affected only by grasses, the performance that ingested elephantgrass was higher. The nutritional composition of the elephantgrass was slightly better than that of mombaçagrass what probably provided better weight gains for the animals in this treatment

Goal-directed therapy in patients with early acute kidney injury: a multicenter randomized controlled trial

OBJECTIVES: Acute kidney injury is associated with many conditions, and no interventions to improve the outcomes of established acute kidney injury have been developed. We performed this study to determine whether goal-directed therapy conducted during the early stages of acute kidney injury could change the course of the disease. METHODS: This was a multicenter prospective randomized controlled study. Patients with early acute kidney injury in the critical care unit were randomly allocated to a standard care (control) group or a goal-directed therapy group with 8h of intensive treatment to maximize oxygen delivery, and all patients were evaluated during a period of 72h. ClinicalTrials.gov: NCT02414906. RESULTS: A total of 143 patients were eligible for the study, and 99 patients were randomized. Central venous oxygen saturation was significantly increased and the serum lactate level significantly was decreased from baseline levels in the goal-directed therapy group (p=0.001) compared to the control group (p=0.572). No significant differences in the change in serum creatinine level (p=0.96), persistence of acute kidney injury beyond 72h (p=0.064) or the need for renal replacement therapy (p=0.82) were observed between the two groups. In-hospital mortality was significantly lower in the goal-directed therapy group than in the control group (33% vs. 51%; RR: 0.61, 95% CI: 0.37-1.00, p=0.048, number needed to treat=5). CONCLUSIONS: Goal-directed therapy for patients in the early stages of acute kidney injury did not change the disease course

Water type and irrigation time effects on microbial metabolism of a soil cultivated with Bermuda-grass Tifton 85

This study investigated the microbial metabolism in Bermuda-grass Tifton 85 areas after potable-water and effluent irrigation treatments. The experiment was carried out in Lins/SP with samples taken in the rainy and dry seasons (2006) after one year and three years of irrigation management, and set up on an entirely randomized block design with four treatments: C (control, without irrigation or fertilization), PW (potable water + 520 kg of N ha-1 year-1); TE3 and TE0 (treated effluent + 520 kg of N ha-1 year-1) for three years and one year, respectively. The parameters determined were: microbial biomass carbon, microbial activity, and metabolic quotient. Irrigation with wastewater after three years indicated no alteration in soil quality for C and ET3; for PW, a negative impact on soil quality (microbial biomass decrease) suggested that water-potable irrigation in Lins is not an adequate option. Microbial activity alterations observed in TE0 characterize a priming effect

Efeito de sistemas de uso e manejo nas propriedades físico-hídricas de um argissolo amarelo de tabuleiro costeiro Effect of use and management systems on the physical and hydraulic properties of a yellow argisol of coastal tablelands

Os diferentes sistemas de manejo com cana-de-açúcar em solos de tabuleiros costeiros podem causar alterações na estrutura original do solo. Os efeitos de diferentes sistemas de manejo com cana-de-açúcar nas propriedades físico-hídricas de um Argissolo Amarelo coeso foram estudados em quatro áreas selecionadas na usina Triunfo, no Estado de Alagoas. Os tratamentos consistiram de uma área não irrigada, uma área irrigada, uma com aplicação de vinhaça e uma sob floresta nativa como condição original. As amostras foram retiradas das profundidades de 0-0,2, 0,2-0,4 e 0,4-0,8 m, para determinar as alterações na densidade do solo, distribuição de diâmetro dos poros, curvas de retenção de água no solo e condutividade hidráulica saturada. O maior grau de dispersão de argila nos solos cultivados com cana-de-açúcar promoveu maior acúmulo desta partícula nas camadas subsuperficiais do solo. Os sistemas de manejo com cana-de-açúcar aumentaram a compactação do solo, com conseqüente redução da macroporosidade e condutividade hidráulica saturada, e aumento da retenção de água disponível do solo.<br>Different sugarcane management systems on soils of coastal tablelands can cause alterations in their original soil structure. Effects of the different sugarcane management systems on the properties of a cohesive Yellow Argisol were studied in four areas of the Triunfo sugar mill in Alagoas State, Brazil. The treatments consisted of a site with and without cultivation irrigation each, one site with vinasse application and another under undisturbed native forest. Samples were collected at depths of 0-0.2, 0.2-0.4 and 0.4-0.8 m to determine the alterations in the bulk density, soil pore size distribution, soil water retention curves, and saturated hydraulic conductivity. The highest degree of clay dispersion in sugarcane-cultivated soils promoted a greater accumulation of clay particles in the subsurface soil layers. Management systems with sugarcane increased soil compaction, with a consequent alteration of the soil pore size distribution, reduced the saturated hydraulic conductivity and increased the retention of available water

Thresholds of freshwater biodiversity in response to riparian vegetation loss in the Neotropical region

Protecting riparian vegetation around streams is vital in reducing the detrimental effects of environmental change on freshwater ecosystems and in maintaining aquatic biodiversity. Thus, identifying ecological thresholds is useful for defining regulatory limits and for guiding the management of riparian zones towards the conservation of freshwater biota. Using nationwide data on fish and invertebrates occurring in small Brazilian streams, we estimated thresholds of native vegetation loss in which there are abrupt changes in the occurrence and abundance of freshwater bioindicators and tested whether there are congruent responses among different biomes, biological groups and riparian buffer sizes. Mean thresholds of native vegetation cover loss varied widely among biomes, buffer sizes and biological groups: ranging from 0.5% to 77.4% for fish, from 2.9% to 37.0% for aquatic invertebrates and from 3.8% to 43.2% for a subset of aquatic invertebrates. Confidence intervals for thresholds were wide, but the minimum values of these intervals were lower for the smaller riparian buffers (50 and 100 m) than larger ones (200 and 500 m), indicating that land use should be kept away from the streams. Also, thresholds occurred at a lower percentage of riparian vegetation loss in the smaller buffers, and were critically lower for invertebrates: reducing only 6.5% of native vegetation cover within a 50-m riparian buffer is enough to cross thresholds for invertebrates. Synthesis and applications. The high variability in biodiversity responses to loss of native riparian vegetation suggests caution in the use of a single riparian width for conservation actions or policy definitions nationwide. The most sensitive bioindicators can be used as early warning signals of abrupt changes in freshwater biodiversity. In practice, maintaining at least 50-m wide riparian reserves on each side of streams would be more effective to protect freshwater biodiversity in Brazil. However, incentives and conservation strategies to protect even wider riparian reserves (~100 m) and also taking into consideration the regional context will promote a greater benefit. This information should be used to set conservation goals and to create complementary mechanisms and policies to protect wider riparian reserves than those currently required by the federal law

Thresholds of freshwater biodiversity in response to riparian vegetation loss in the Neotropical region

Protecting riparian vegetation around streams is vital in reducing the detrimental effects of environmental change on freshwater ecosystems and in maintaining aquatic biodiversity. Thus, identifying ecological thresholds is useful for defining regulatory limits and for guiding the management of riparian zones towards the conservation of freshwater biota. Using nationwide data on fish and invertebrates occurring in small Brazilian streams, we estimated thresholds of native vegetation loss in which there are abrupt changes in the occurrence and abundance of freshwater bioindicators and tested whether there are congruent responses among different biomes, biological groups and riparian buffer sizes. Mean thresholds of native vegetation cover loss varied widely among biomes, buffer sizes and biological groups: ranging from 0.5% to 77.4% for fish, from 2.9% to 37.0% for aquatic invertebrates and from 3.8% to 43.2% for a subset of aquatic invertebrates. Confidence intervals for thresholds were wide, but the minimum values of these intervals were lower for the smaller riparian buffers (50 and 100 m) than larger ones (200 and 500 m), indicating that land use should be kept away from the streams. Also, thresholds occurred at a lower percentage of riparian vegetation loss in the smaller buffers, and were critically lower for invertebrates: reducing only 6.5% of native vegetation cover within a 50-m riparian buffer is enough to cross thresholds for invertebrates. Synthesis and applications. The high variability in biodiversity responses to loss of native riparian vegetation suggests caution in the use of a single riparian width for conservation actions or policy definitions nationwide. The most sensitive bioindicators can be used as early warning signals of abrupt changes in freshwater biodiversity. In practice, maintaining at least 50-m wide riparian reserves on each side of streams would be more effective to protect freshwater biodiversity in Brazil. However, incentives and conservation strategies to protect even wider riparian reserves (~100 m) and also taking into consideration the regional context will promote a greater benefit. This information should be used to set conservation goals and to create complementary mechanisms and policies to protect wider riparian reserves than those currently required by the federal law. © 2020 British Ecological Societ

Data and R-code from 'Mode of death and mortality risk factors in Amazon trees'. Nature communications. 2020

The carbon sink capacity of tropical forests is substantially affected by tree mortality. However, the main drivers of tropical tree death remain largely unknown. Here we present a pan-Amazonian assessment of how and why trees die, analysing over 120,000 trees representing > 3800 species from 189 long-term RAINFOR forest plots. While tree mortality rates vary greatly Amazon-wide, on average trees are as likely to die standing as they are broken or uprooted—modes of death with different ecological consequences. Species-level growth rate is the single most important predictor of tree death in Amazonia, with faster-growing species being at higher risk. Within species, however, the slowest-growing trees are at greatest risk while the effect of tree size varies across the basin. In the driest Amazonian region species-level bioclimatic distributional patterns also predict the risk of death, suggesting that these forests are experiencing climatic conditions beyond their adaptative limits. These results provide not only a holistic pan-Amazonian picture of tree death but large-scale evidence for the overarching importance of the growth–survival trade-off in driving tropical tree mortality

Brazilian Flora 2020: Leveraging the power of a collaborative scientific network

International audienceThe shortage of reliable primary taxonomic data limits the description of biological taxa and the understanding of biodiversity patterns and processes, complicating biogeographical, ecological, and evolutionary studies. This deficit creates a significant taxonomic impediment to biodiversity research and conservation planning. The taxonomic impediment and the biodiversity crisis are widely recognized, highlighting the urgent need for reliable taxonomic data. Over the past decade, numerous countries worldwide have devoted considerable effort to Target 1 of the Global Strategy for Plant Conservation (GSPC), which called for the preparation of a working list of all known plant species by 2010 and an online world Flora by 2020. Brazil is a megadiverse country, home to more of the world's known plant species than any other country. Despite that, Flora Brasiliensis, concluded in 1906, was the last comprehensive treatment of the Brazilian flora. The lack of accurate estimates of the number of species of algae, fungi, and plants occurring in Brazil contributes to the prevailing taxonomic impediment and delays progress towards the GSPC targets. Over the past 12 years, a legion of taxonomists motivated to meet Target 1 of the GSPC, worked together to gather and integrate knowledge on the algal, plant, and fungal diversity of Brazil. Overall, a team of about 980 taxonomists joined efforts in a highly collaborative project that used cybertaxonomy to prepare an updated Flora of Brazil, showing the power of scientific collaboration to reach ambitious goals. This paper presents an overview of the Brazilian Flora 2020 and provides taxonomic and spatial updates on the algae, fungi, and plants found in one of the world's most biodiverse countries. We further identify collection gaps and summarize future goals that extend beyond 2020. Our results show that Brazil is home to 46,975 native species of algae, fungi, and plants, of which 19,669 are endemic to the country. The data compiled to date suggests that the Atlantic Rainforest might be the most diverse Brazilian domain for all plant groups except gymnosperms, which are most diverse in the Amazon. However, scientific knowledge of Brazilian diversity is still unequally distributed, with the Atlantic Rainforest and the Cerrado being the most intensively sampled and studied biomes in the country. In times of “scientific reductionism”, with botanical and mycological sciences suffering pervasive depreciation in recent decades, the first online Flora of Brazil 2020 significantly enhanced the quality and quantity of taxonomic data available for algae, fungi, and plants from Brazil. This project also made all the information freely available online, providing a firm foundation for future research and for the management, conservation, and sustainable use of the Brazilian funga and flora