45 research outputs found
Dominância, distribuição e diversidade de palmeiras ao longo de gradientes ambientais na Amazônia
The aim of this thesis was to study the patterns of dominance, diversity and species distribution in Amazonian palms. In the first chapter we explored the continental patterns of variation in palm species dominance by relating palm and tree basal area with soil physical properties. In this chapter, we showed that soil physical properties establish the upper limit for palm and tree basal area and that the direction of this relationship differs between them. As soil resistance to root penetration heightens, tree basal area decreases and palm basal area increases. The mechanism of forest partitioning by palms as trees is related to forest structure at the local scale and with forest physiognomy at the basin scale. In the second chapter we explored the regional patterns of palm species abundance variation in relation to environmental gradients and their effect on dominance and floristic composition patterns. In this chapter we demonstrate that subtle and abrupt differences in floristic composition may be caused by changes in species abundance in relation to environmental conditions. We also showed that dominance patterns are linked with the patterns of floristic variation and suggest a mechanism to explain the occurrence of dominance in tropical forests. In the third chapter, we tested the hypothesis that species segregation along subtle environmental gradients will explain species coexistence in local and regional scale. In this chapter, we showed that palm species are segregated along a hydrological axis of soil moisture and that the hydrological niche affiliation of the species is a character that evolved through palm evolution andO objetivo desta tese foi estudar os padrões de dominância, diversidade e distribuição de palmeiras na AmazĂ´nia. No primeiro capĂtulo, exploramos os padrões continentais de variação na dominância de palmeiras relacionando a área basal de palmeiras e árvores com propriedades fĂsicas do solo. Neste capitulo, mostramos que a área basal de árvores e palmeiras Ă© limitada pelas condições fĂsicas do solo e que a direção desta relação varia entre os grupos. Quanto maior a resistĂŞncia dos solos a penetração de raĂzes, menor a área basal de árvores e maior a de palmeiras. Este mecanismo de partição da floresta por árvores e palmeiras está relacionado com a estrutura da floresta em escala local e com a fisionomia da floresta na escala da bacia. No segundo capitulo, exploramos os padrões regionais de variação da abundância das espĂ©cies de palmeiras em relação a gradientes ambientais e seus efeitos sobre os padrões de dominância e composição florĂstica. Neste capĂtulo, evidenciamos que tanto diferenças sutis, quanto diferenças abruptas na composição florĂstica podem ser causadas por variações na abundância das espĂ©cies em resposta a condições ambientais. Mostramos ainda que os padrões de dominância estĂŁo relacionados com os padrões de variação florĂstica e sugerimos um possĂvel mecanismo para explicar a ocorrĂŞncia de dominância em florestas tropicais. No terceiro capĂtulo, testamos a hipĂłtese de que a segregação de espĂ©cies em gradientes ambientais sutis poderia explicar a coexistĂŞncia de espĂ©cies em escala local e regional. Neste capĂtulo, mostramos que espĂ©cies de palmeiras estĂŁo segregadas em eixos hidrolĂłgicos de saturação e seca do solo, que a afiliação das espĂ©cies a nichos hidrolĂłgicos Ă© um caractere lábil ao longo da evolução das palmeiras e que a segregação de espĂ©cies nestes eixos de nich
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
Author correction: One sixth of Amazonian tree diversity is dependent on river floodplains
In the version of the article initially published, the affiliation of Edgardo Manuel Latrubesse was incorrect and has now been amended to Environmental Sciences Graduate Program-CIAMB, Federal University of Goiás, Goiânia, Brazil in the HTML and PDF versions of the article
One sixth of Amazonian tree diversity is dependent on river floodplains
Amazonia’s floodplain system is the largest and most biodiverse on Earth. Although forests are crucial to the ecological integrity of floodplains, our understanding of their species composition and how this may differ from surrounding forest types is still far too limited, particularly as changing inundation regimes begin to reshape floodplain tree communities and the critical ecosystem functions they underpin. Here we address this gap by taking a spatially explicit look at Amazonia-wide patterns of tree-species turnover and ecological specialization of the region’s floodplain forests. We show that the majority of Amazonian tree species can inhabit floodplains, and about a sixth of Amazonian tree diversity is ecologically specialized on floodplains. The degree of specialization in floodplain communities is driven by regional flood patterns, with the most compositionally differentiated floodplain forests located centrally within the fluvial network and contingent on the most extraordinary flood magnitudes regionally. Our results provide a spatially explicit view of ecological specialization of floodplain forest communities and expose the need for whole-basin hydrological integrity to protect the Amazon’s tree diversity and its function
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
Unraveling Amazon tree community assembly using Maximum Information Entropy: a quantitative analysis of tropical forest ecology
In a time of rapid global change, the question of what determines patterns in species abundance distribution remains a priority for understanding the complex dynamics of ecosystems. The constrained maximization of information entropy provides a framework for the understanding of such complex systems dynamics by a quantitative analysis of important constraints via predictions using least biased probability distributions. We apply it to over two thousand hectares of Amazonian tree inventories across seven forest types and thirteen functional traits, representing major global axes of plant strategies. Results show that constraints formed by regional relative abundances of genera explain eight times more of local relative abundances than constraints based on directional selection for specific functional traits, although the latter does show clear signals of environmental dependency. These results provide a quantitative insight by inference from large-scale data using cross-disciplinary methods, furthering our understanding of ecological dynamics
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
Unraveling Amazon tree community assembly using Maximum Information Entropy: a quantitative analysis of tropical forest ecology
In a time of rapid global change, the question of what determines patterns in species abundance distribution remains a priority for understanding the complex dynamics of ecosystems. The constrained maximization of information entropy provides a framework for the understanding of such complex systems dynamics by a quantitative analysis of important constraints via predictions using least biased probability distributions. We apply it to over two thousand hectares of Amazonian tree inventories across seven forest types and thirteen functional traits, representing major global axes of plant strategies. Results show that constraints formed by regional relative abundances of genera explain eight times more of local relative abundances than constraints based on directional selection for specific functional traits, although the latter does show clear signals of environmental dependency. These results provide a quantitative insight by inference from large-scale data using cross-disciplinary methods, furthering our understanding of ecological dynamics