Estratégias funcionais das espécies dominantes na sucessão florestal na Amazônia Central

The study of the functions performed by species in plant communities makes an important contribution to understanding the dynamics of communities and their effects on ecosystem functioning. Thus, community assembly patterns may be better understood in this functional perspective when compared to a strictly taxonomic perspective and comparisons between regions and biomes become feasible through the functional traits. The functional traits dynamics along secondary succession is a good opportunity to analyze the communities’ assemblies in face the ecological factors that cause these forests. The role of dominant species is crucial in this process because they reflect the responses to disturbances and contribute to the initial dynamics of ecosystem functioning. Thus, this study analyzed the functional traits dynamics of the dominant species in two successional trajectories in secondary forests north of Manaus. For this, the data collected over 14 years by Projeto Pioneiras at Biological Dynamics of Forest Fragments Project were used to calculate the dominant species in basal area in the forests converted to pasture (FCP) and the clear-cut vegetation forest (FCR). Leaf area, Leaf Dry Mass Content, Specific Leaf Area and Wood Density were the functional traits collected for 167 individuals of 26 species and had their community weighted mean (CWM) calculated according to basal area in the year evaluated for each transect. The height and diameter at breast height were also collected and the Seed Weight was obtained through literature. In FCP was obtained only one significant relationship to the succession of time: the CWM – Wood Density. For FCR CWM - Leaf Area, Leaf Dry Mass Content, Specific Leaf Area and Seed Weight had significant relationships varying with the line slope. The functional trajectory of transects shows that clear cut forests have a greater extent than the forest derived from pasture and an apparent directionality in succession. The functional richness (FRic) showed no significant difference between the areas, but this is marginally significant (t = 2.0504, p = 0.0659). These results corroborate other studies on the possibility of succession lying arrested in forests derived from agricultural activity, which can result in loss of species and functional diversity, forest's resilience to support future impacts and its ecosystem services declining in quality.O estudo das funções desempenhadas pelas espécies nas comunidades vegetais traz uma importante contribuição na compreensão da dinâmica das comunidades e seus efeitos no funcionamento do ecossistema. Deste modo, padrões de organização das comunidades podem ser melhor compreendidos nesta perspectiva funcional quando comparados com uma perspectiva estritamente taxonômica, e comparações entre regiões e biomas tornam-se factíveis através dos atributos funcionais. A dinâmica de atributos funcionais ao longo da sucessão secundária é uma boa oportunidade para analisar a organização de comunidades frente aos fatores ecológicos que originam estas florestas. O papel das espécies dominantes é fundamental neste processo, pois, estas refletem as respostas aos distúrbios e contribuem na dinâmica inicial do funcionamento do ecossistema. Sendo assim, este trabalho analisou a dinâmica de atributos funcionais das espécies dominantes em duas trajetórias sucessionais em florestas secundárias ao norte de Manaus. Para isso, os dados coletados ao longo de 14 anos pelo Projeto Pioneiras do Projeto de Dinâmica Biológica de Fragmentos Florestais foram utilizados para calcular as espécies dominantes em área basal nas florestas convertidas a pastagem (FCP) e nas florestas de corte raso da vegetação (FCR). Área Foliar, Teor de Massa Seca da Folha, Área Foliar Específica e Densidade da Madeira foram os atributos funcionais coletados para 167 indivíduos de 26 espécies e tiveram suas médias ponderadas da comunidade (CWM) calculadas conforme a área basal no ano avaliado para cada transecto. A Altura e Diâmetro a Altura do Peito também foram coletados e o Peso das Sementes foi obtido através de dados da literatura. Para as FCP foi obtida apenas uma relação significativa com o tempo de sucessão: o CWM – Densidade da Madeira. Para as FCR o CWM – Área Foliar, Teor de Massa Seca da Folha, Área Foliar Específica e Peso das Sementes tiveram relações significativas variando conforme a inclinação da reta. A trajetória funcional dos transectos demonstra que as florestas de corte raso possuem uma maior extensão do que as florestas derivadas de pastagem e uma aparente direcionalidade na sucessão. A riqueza funcional (FRic) não apresentou diferença significativa entre as áreas, porém este valor é marginalmente significativo (t = 2,0504, p = 0,0659). Estes resultados corroboram com outros estudos sobre a possibilidade da sucessão encontrar-se estagnada em florestas derivadas da atividade agropecuária, o que pode resultar em perda da diversidade de espécies e funcional, da capacidade da floresta em suportar impactos futuros e que os seus serviços ecossistêmicos decaiam em qualidade

Fósforo e atividade da fosfatase ácida em plantas de feijoeiro

The objective of this work was to evaluate the influence of the soil class, conditions of use and practices of correction of soil fertility upon dry matter production, phosphorus accumulation, phosphorus fractions and activity of acid phosphatase in vivo in common bean (Phaseolus vulgaris L.) plants. The study was conducted at greenhouse conditions of the Soil Science Department of the Universidade Federal de Lavras, Minas Gerais, Brazil, with two soils (Oxisol and Ultisol), under three conditions of use and four practices of correction of soil fertility. The highest dry matter production and P utilization efficiency was observed in plants cultivated in the Oxisol, which provided minor Pi accumulated than in the Ultisol. The activity of acid phosphatase in vivo did not reflect the nutritional state of bean plants.O objetivo deste trabalho foi avaliar a influência da classe de solo, das condições de uso e das práticas culturais de correção da fertilidade do solo na produção de matéria seca, acúmulo de fósforo, frações de fósforo e atividade da fosfatase ácida in vivo em plantas de feijoeiro (Phaseolus vulgaris L.). O estudo foi conduzido em casa de vegetação do Departamento de Ciência do Solo da Universidade Federal de Lavras, com dois solos (Latossolo Roxo e Terra Roxa Estruturada), sob três condições de uso e sob quatro práticas culturais de correção da fertilidade do solo. A maior produção de matéria seca e eficiência de utilização de fósforo ocorreram nas plantas cultivadas no Latossolo Roxo, que também proporcionou menor acúmulo de fósforo inorgânico nos tecidos foliares. A atividade da fosfatase ácida in vivo não refletiu o estado nutricional das plantas de feijoeiro

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

A ética do silêncio racial no contexto urbano: políticas públicas e desigualdade social no Recife, 1900-1940

Mais de meio século após o preconceito racial ter se tornado o principal alvo dos movimentos urbanos pelos direitos civis nos Estados Unidos e na África do Sul, e décadas depois do surgimento dos movimentos negros contemporâneos no Brasil, o conjunto de ferramentas legislativas criado no Brasil para promover o direito à cidade ainda adere à longa tradição brasileira de silêncio acerca da questão racial. Este artigo propõe iniciar uma exploração das raízes históricas desse fenômeno, remontando ao surgimento do silêncio sobre a questão racial na política urbana do Recife, Brasil, durante a primeira metade do século XX. O Recife foi eé um exemplo paradigmático do processo pelo qual uma cidade amplamente marcada por traços negros e africanos chegou a ser definida política e legalmente como um espaço pobre, subdesenvolvido e racialmente neutro, onde as desigualdades sociais originaram na exclusão capitalista, e não na escravidão e nas ideologias do racismo científico. Neste sentido, Recife lança luzes sobre a política urbana que se gerou sob a sombra do silêncio racial.More than half a century after racial prejudice became central to urban civil rights movements in the United States and South Africa, and decades after the emergence of Brazil’s contemporary Black movements, Brazil's internationally recognized body of rights-to-the-city legislation still adheres to the country's long historical tradition of racial silence. This article explores the historical roots of this phenomenon by focusing on the emergence of racial silence in Recife, Brazil during the first half of the 20th Century. Recife was and remains a paradigmatic example of the process through which a city marked by its Black and African roots came to be legally and politically defined as a poor, underdeveloped and racially neutral space, where social inequalities derived from capitalist exclusion rather than from slavery and scientific racism. As such, Recife'sexperience sheds light on the urban policies that were generated in the shadow of racial silence

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 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

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 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