31 research outputs found

    Perspectivas Macroecol√≥gicas Nas √Āreas √ömidas Dominadas Por Mauritia Na Amaz√īnia

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    The palm genus Mauritia L.f (Arecaceae) is a principal component of Neotropical freshwater swamp and flooded-savanna vegetation. As such, these palms indicate near-permanent waterlogging at or near ground surface. In this study, expeditionary and exploratory research was undertaken to sample the woody vegetation communities of Mauritia-dominated wetlands (MDWs). A total of 28 MDWs were quantitatively sampled in the Brazilian and Peruvian Amazon. Field work resulted in >3000 botanical collections accompanied by >8000 photographic images made publically available through online resources (http://atrium.andesamazon.org/). Over 40,000 individual woody stems were documented, distributed among 89 families, 318 genera and ~750 woody species. Taking advantage of the indicator status of Mauritia for near-permanently waterlogged substrates ‚Äď an extreme abiotic condition in the region - the community ecology of woody vegetation of this common Amazonian wetland habitat was investigated across a broad spatial scale regarding its taxonomic, phylogenetic, and biogeographic structure. Data indicate reduced local site richness in MDW vegetation communities, consistent with previous investigation. Over broad spatial scales results show that rather than being comprised of a predictable set of habitat specialists, MDWs exhibit high site-to-site compositional variability relative to surrounding upland forest vegetation. Community phylogenetic analyses reveal that the ability to occupy MDWs is widely distributed in a phylogenetically diverse array of Amazonian forest taxa. Biogeographic analyses reveal that assemblages demonstrate consistent patterns of compositional turnover along local stress gradients, transitioning from largely Amazonian-distributed lineages in forested sites to increasingly extra-Amazoniandistributed lineages in shrubby sites. I suggest that traditionally perceived patterns of community homogeneity of MDWs occur alongside previously underappreciated patterns of taxonomic, phylogenetic, and functional diversity. Taking the results together, I argue that comparative analyses of MDW communities offer unique insight into current models of Amazonian plant and ecosystem diversity that are based almost completely on upland forests, contributing to both Amazonian biodiversity theory (Chapter 1 and 2) and applied science (Chapter 3).O g√™nero das palmeiras Mauritia L.f. (Arecaceae) √© o componente principal de √°reas pantanosas neotropicais e da vegeta√ß√£o de muitas savanas inundadas. A presen√ßa deste g√™nero indica condi√ß√Ķes de inunda√ß√£o permanente na superf√≠cie e/ou pr√≥ximo √† superf√≠cie do solo. No presente estudo, foram realizados invent√°rios flor√≠sticos em comunidades lenhosas de √°reas √ļmidas dominadas por Mauritia, os buritizais. Na Amaz√īnia brasileira e peruana, um n√ļmero total de 28 buritizais foi inventariado. O trabalho de campo resultou em mais de 3.000 coletas bot√Ęnicas, e mais de 8.000 fotografias, publicamente acess√≠veis em herb√°rio digital (http://atrium.andesamazon.org/). Mais de 40.000 indiv√≠duos lenhosos foram levantados, distribu√≠dos em 89 fam√≠lias, 318 g√™neros e aproximadamente 750 esp√©cies. Utilizando o g√™nero Mauritia como indicador de substratos permanentemente alagados, uma condi√ß√£o abi√≥tica extrema na regi√£o, a ecologia da comunidade lenhosa deste importante habitat √ļmido Amaz√īnico foi investigada ao longo de uma grande escala espacial em fun√ß√£o de sua composi√ß√£o taxon√īmica, filogen√©tica e biogeogr√°fica. Os dados indicam que a comunidade de vegeta√ß√£o dos buritizais apresenta uma riqueza flor√≠stica reduzida, consistente com o conhecimento dispon√≠vel em literatura. Ao longo de ampla escala espacial, os resultados indicam que os buritizais apresentam uma alta variabilidade na composi√ß√£o flor√≠stica entre diferentes s√≠tios em compara√ß√£o com a flora de terra firme. As analises filogen√©ticas revelaram que o uso do habitat de buritizais provavelmente √© um atributo amplamente presente na filogenia de ecossistemas florestados Amaz√īnicos. As analises biogeogr√°ficas mostraram que as comunidades demonstram um padr√£o consistente de substitui√ß√£o composicional ao longo de gradientes de estresse, com uma transi√ß√£o de linhagens majoritariamente Amaz√īnicas em s√≠tios florestados para linhagens majoritariamente extraamaz√īnicas em s√≠tios arbustivos. √Č sugerido que o padr√£o de homogeneidade flor√≠stica dos buritizais, como tradicionalmente notado, ocorre em conjunto com um padr√£o de alta diversidade taxon√īmica, filogen√©tica e funcional, fato muitas vezes subestimado at√© o momento. Argumenta-se que as an√°lises comparativas de comunidades de buritizais oferecem uma abordagem inovadora e √ļnica sobre os recentes modelos de diversidade especifica e ecossist√™mica, que at√© o presente, baseiam-se quase que inteiramente em florestas de terra firme. Desta maneira, os resultados aqui apresentados contribuem tanto para as teorias de biodiversidade nos cap√≠tulos 1 e 2, quanto para a ci√™ncia aplicada no capitulo 3

    Using the River Ecosystem Service Index to evaluate ‚ÄúFree Moving Rivers‚Ä̬†restoration measures: A case study on the Ammer river (Bavaria)

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    Restoring natural fluvial dynamics is fundamental for sustaining biodiversity and functional integrity of river and floodplain ecosystems. In Central Europe, however, pervasive river regulation and bank protection have greatly impaired ecosystem functioning and many water bodies fail to achieve a good ecological status within the European Water Framework Directive. The ‚ÄúFree Moving Rivers‚ÄĚ approach seeks to restore the ecological integrity of rivers and floodplains by creating appropriate conditions for natural fluvial dynamics. Principal goals of the approach include removing artificial constraints on river processes and expanding the river corridor to restore natural river habitats and structures. Lacking, however, are complementary tools that evaluate and predict changes to ecosystem services (ESSs) after implementation. Here, we describe a case study of the Ammer river in Bavaria, Germany, to (i) calculate the extent of the ‚ÄúFree Moving Rivers‚ÄĚ corridor, and (ii) assess changes to ESSs of a proposed river restoration measure under two alternative land-use scenarios. To do this, we apply the River Ecosystem Service Index (RESI), whereby individual ESSs are assessed in a spatially explicit way. We show how a proposed implementation of the ‚ÄúFree Moving Rivers‚ÄĚ approach enhances three investigated ESSs: flood retention, sediment balance and habitat provision. We conclude that RESI is a potentially useful tool with wide applicability for restoration planning that synthesises floodplain complexity in such a way that facilitates decision making

    A Review of the Ecological and Biogeographic Differences of Amazonian Floodplain Forests

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    Amazonian floodplain forests along large rivers consist of two distinct floras that are traced to their differentiated sediment- and nutrient-rich (v√°rzea) or sediment- and nutrient-poor (igap√≥) environments. While tree species in both ecosystems have adapted to seasonal floods that may last up to 270‚Äď300 days year‚ąí1, ecosystem fertility, hydrogeomorphic disturbance regimes, water shortage and drought, fire, and even specific microclimates are distinct between both ecosystems and largely explain the differences in forest productivity and taxonomic composition and diversity. Here, we review existing knowledge about the influence of these environmental factors on the tree flora of both ecosystems, compare species composition and diversity between central Amazonian v√°rzeas and igap√≥s, and show that both ecosystems track distinct species life-history traits. The ecosystem-level and taxonomic differences also largely explain the biogeographic connections of v√°rzeas and igap√≥s to other Amazonian and extra-Amazonian ecosystems. We highlight the major evolutionary force of large-river wetlands for Amazonian tree diversity and explore the scenarios by which the large number of Amazonian floodplain specialist tree species might even contribute to the gamma diversity of the Amazon by generating new species. Finally, we call attention to the urgent need of an improved conservation of Amazonian v√°rzea and igap√≥ ecosystems and their tree species

    Soil fertility and drought interact to determine large variations in wood production for a hyperdominant Amazonian tree species

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    Introduction: The productivity of the Amazon Rainforest is related to climate and soil fertility. However, the degrees to which these interactions influence multiannual to decadal variations in tree diameter growth are still poorly explored. Methods: To fill this gap, we used radiocarbon measurements to evaluate the variation in tree growth rates over the past decades in an important hyperdominant species, Eschweilera coriacea (Lecythidaceae), from six sites in the Brazilian Amazon that span a range of soil properties and climate. Results: Using linear mixed-effects models, we show that temporal variations in mean annual diameter increment evaluated over a specific time period reflect interactions between soil fertility and the drought index (SPEI-Standardized Precipitation and Evapotranspiration Index). Discussion: Our results indicate that the growth response of trees to drought is strongly dependent on soil conditions, a facet of forest productivity that is still underexplored, and which has great potential for improving predictions of future tropical tree growth in the face of projected climate change

    Risks to carbon storage from land-use change revealed by peat thickness maps of Peru

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    This work was funded by NERC (grant ref. NE/R000751/1) to I.T.L., A.H., K.H.R., E.T.A.M., C.M.A., T.R.B., G.D. and E.C.D.G.; Leverhulme Trust (grant ref. RPG-2018-306) to K.H.R., L.E.S.C. and C.E.W.; Gordon and Betty Moore Foundation (grant no. 5439, MonANPeru network) to T.R.B., E.N.H.C. and G.F.; Wildlife Conservation Society to E.N.H.C.; Concytec/British Council/Embajada Brit√°nica Lima/Newton Fund (grant ref. 220‚Äď2018) to E.N.H.C. and J.D.; Concytec/NERC/Embajada Brit√°nica Lima/Newton Fund (grant ref. 001‚Äď2019) to E.N.H.C. and N.D.; the governments of the United States (grant no. MTO-069018) and Norway (grant agreement no. QZA-12/0882) to K.H.; and NERC Knowledge Exchange Fellowship (grant ref no. NE/V018760/1) to E.N.H.C.Tropical peatlands are among the most carbon-dense ecosystems but land-use change has led to the loss of large peatland areas, associated with substantial greenhouse gas emissions. To design effective conservation and restoration policies, maps of the location and carbon storage of tropical peatlands are vital. This is especially so in countries such as Peru where the distribution of its large, hydrologically intact peatlands is poorly known. Here field and remote sensing data support the model development of peatland extent and thickness for lowland Peruvian Amazonia. We estimate a peatland area of 62,714‚ÄČkm2 (5th and 95th confidence interval percentiles of 58,325 and 67,102‚ÄČkm2, respectively) and carbon stock of 5.4 (2.6‚Äď10.6)‚ÄČPgC, a value approaching the entire above-ground carbon stock of Peru but contained within just 5% of its land area. Combining the map of peatland extent with national land-cover data we reveal small but growing areas of deforestation and associated CO2 emissions from peat decomposition due to conversion to mining, urban areas and agriculture. The emissions from peatland areas classified as forest in 2000 represent 1‚Äď4% of Peruvian CO2 forest emissions between 2000 and 2016. We suggest that bespoke monitoring, protection and sustainable management of tropical peatlands are required to avoid further degradation and CO2 emissions.PostprintPeer reviewe

    Geographic patterns of tree dispersal modes in Amazonia and their ecological correlates

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    Aim: To investigate the geographic patterns and ecological correlates in the geographic distribution of the most common tree dispersal modes in Amazonia (endozoochory, synzoochory, anemochory and hydrochory). We examined if the proportional abundance of these dispersal modes could be explained by the availability of dispersal agents (disperser-availability hypothesis) and/or the availability of resources for constructing zoochorous fruits (resource-availability hypothesis). Time period: Tree-inventory plots established between 1934 and 2019. Major taxa studied: Trees with a diameter at breast height (DBH) ‚Č•‚ÄČ9.55‚ÄČcm. Location: Amazonia, here defined as the lowland rain forests of the Amazon River basin and the Guiana Shield. Methods: We assigned dispersal modes to a total of 5433 species and morphospecies within 1877 tree-inventory plots across terra-firme, seasonally flooded, and permanently flooded forests. We investigated geographic patterns in the proportional abundance of dispersal modes. We performed an abundance-weighted mean pairwise distance (MPD) test and fit generalized linear models (GLMs) to explain the geographic distribution of dispersal modes. Results: Anemochory was significantly, positively associated with mean annual wind speed, and hydrochory was significantly higher in flooded forests. Dispersal modes did not consistently show significant associations with the availability of resources for constructing zoochorous fruits. A lower dissimilarity in dispersal modes, resulting from a higher dominance of endozoochory, occurred in terra-firme forests (excluding podzols) compared to flooded forests. Main conclusions: The disperser-availability hypothesis was well supported for abiotic dispersal modes (anemochory and hydrochory). The availability of resources for constructing zoochorous fruits seems an unlikely explanation for the distribution of dispersal modes in Amazonia. The association between frugivores and the proportional abundance of zoochory requires further research, as tree recruitment not only depends on dispersal vectors but also on conditions that favour or limit seedling recruitment across forest types

    Mapping density, diversity and species-richness of the Amazon tree flora

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    Using 2.046 botanically-inventoried tree plots across the largest tropical forest on Earth, we mapped tree species-diversity and tree species-richness at 0.1-degree resolution, and investigated drivers for diversity and richness. Using only location, stratified by forest type, as predictor, our spatial model, to the best of our knowledge, provides the most accurate map of tree diversity in Amazonia to date, explaining approximately 70% of the tree diversity and species-richness. Large soil-forest combinations determine a significant percentage of the variation in tree species-richness and tree alpha-diversity in Amazonian forest-plots. We suggest that the size and fragmentation of these systems drive their large-scale diversity patterns and hence local diversity. A model not using location but cumulative water deficit, tree density, and temperature seasonality explains 47% of the tree species-richness in the terra-firme forest in Amazonia. Over large areas across Amazonia, residuals of this relationship are small and poorly spatially structured, suggesting that much of the residual variation may be local. The Guyana Shield area has consistently negative residuals, showing that this area has lower tree species-richness than expected by our models. We provide extensive plot meta-data, including tree density, tree alpha-diversity and tree species-richness results and gridded maps at 0.1-degree resolution

    Unraveling Amazon tree community assembly using Maximum Information Entropy: a quantitative analysis of tropical forest ecology

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    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

    Unraveling Amazon tree community assembly using Maximum Information Entropy: a quantitative analysis of tropical forest ecology

    Get PDF
    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

    Mapping density, diversity and species-richness of the Amazon tree flora

    Get PDF
    Using 2.046 botanically-inventoried tree plots across the largest tropical forest on Earth, we mapped tree species-diversity and tree species-richness at 0.1-degree resolution, and investigated drivers for diversity and richness. Using only location, stratified by forest type, as predictor, our spatial model, to the best of our knowledge, provides the most accurate map of tree diversity in Amazonia to date, explaining approximately 70% of the tree diversity and species-richness. Large soil-forest combinations determine a significant percentage of the variation in tree species-richness and tree alpha-diversity in Amazonian forest-plots. We suggest that the size and fragmentation of these systems drive their large-scale diversity patterns and hence local diversity. A model not using location but cumulative water deficit, tree density, and temperature seasonality explains 47% of the tree species-richness in the terra-firme forest in Amazonia. Over large areas across Amazonia, residuals of this relationship are small and poorly spatially structured, suggesting that much of the residual variation may be local. The Guyana Shield area has consistently negative residuals, showing that this area has lower tree species-richness than expected by our models. We provide extensive plot meta-data, including tree density, tree alpha-diversity and tree species-richness results and gridded maps at 0.1-degree resolution
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