114 research outputs found

    Perspectivas Macroecológicas Nas Áreas Úmidas Dominadas Por Mauritia Na Amazônia

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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 – 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 gênero das palmeiras Mauritia L.f. (Arecaceae) é o componente principal de áreas pantanosas neotropicais e da vegetação de muitas savanas inundadas. A presença deste gênero indica condições de inundação permanente na superfície e/ou próximo à superfície do solo. No presente estudo, foram realizados inventários florísticos em comunidades lenhosas de áreas úmidas dominadas por Mauritia, os buritizais. Na Amazônia brasileira e peruana, um número total de 28 buritizais foi inventariado. O trabalho de campo resultou em mais de 3.000 coletas botânicas, e mais de 8.000 fotografias, publicamente acessíveis em herbário digital (http://atrium.andesamazon.org/). Mais de 40.000 indivíduos lenhosos foram levantados, distribuídos em 89 famílias, 318 gêneros e aproximadamente 750 espécies. Utilizando o gênero Mauritia como indicador de substratos permanentemente alagados, uma condição abiótica extrema na região, a ecologia da comunidade lenhosa deste importante habitat úmido Amazônico foi investigada ao longo de uma grande escala espacial em função de sua composição taxonômica, filogenética e biogeográfica. Os dados indicam que a comunidade de vegetação dos buritizais apresenta uma riqueza florística reduzida, consistente com o conhecimento disponível em literatura. Ao longo de ampla escala espacial, os resultados indicam que os buritizais apresentam uma alta variabilidade na composição florística entre diferentes sítios em comparação com a flora de terra firme. As analises filogenéticas revelaram que o uso do habitat de buritizais provavelmente é um atributo amplamente presente na filogenia de ecossistemas florestados Amazônicos. As analises biogeográficas mostraram que as comunidades demonstram um padrão consistente de substituição composicional ao longo de gradientes de estresse, com uma transição de linhagens majoritariamente Amazônicas em sítios florestados para linhagens majoritariamente extraamazônicas em sítios arbustivos. É sugerido que o padrão de homogeneidade florística dos buritizais, como tradicionalmente notado, ocorre em conjunto com um padrão de alta diversidade taxonômica, filogenética e funcional, fato muitas vezes subestimado até o momento. Argumenta-se que as análises comparativas de comunidades de buritizais oferecem uma abordagem inovadora e única sobre os recentes modelos de diversidade especifica e ecossistêmica, que até 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 capítulos 1 e 2, quanto para a ciência aplicada no capitulo 3

    Using the River Ecosystem Service Index to evaluate “Free Moving Rivers” 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 “Free Moving Rivers” 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 “Free Moving Rivers” 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 “Free Moving Rivers” 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

    One sixth of Amazonian tree diversity is dependent on river floodplains

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    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

    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 (várzea) or sediment- and nutrient-poor (igapó) environments. While tree species in both ecosystems have adapted to seasonal floods that may last up to 270–300 days year−1, 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 várzeas and igapós, and show that both ecosystems track distinct species life-history traits. The ecosystem-level and taxonomic differences also largely explain the biogeographic connections of várzeas and igapós 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 várzea and igapó 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 Británica Lima/Newton Fund (grant ref. 220–2018) to E.N.H.C. and J.D.; Concytec/NERC/Embajada Británica Lima/Newton Fund (grant ref. 001–2019) 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 km2 (5th and 95th confidence interval percentiles of 58,325 and 67,102 km2, respectively) and carbon stock of 5.4 (2.6–10.6) PgC, 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 1–4% 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

    One sixth of Amazonian tree diversity is dependent on river floodplains

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    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

    A new data-driven map predicts substantial undocumented peatland areas in Amazonia

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    Tropical peatlands are among the most carbon-dense terrestrial ecosystems yet recorded. Collectively, they comprise a large but highly uncertain reservoir of the global carbon cycle, with wide-ranging estimates of their global area (441 025–1700 000 km2) and below-ground carbon storage (105–288 Pg C). Substantial gaps remain in our understanding of peatland distribution in some key regions, including most of tropical South America. Here we compile 2413 ground reference points in and around Amazonian peatlands and use them alongside a stack of remote sensing products in a random forest model to generate the first field-data-driven model of peatland distribution across the Amazon basin. Our model predicts a total Amazonian peatland extent of 251 015 km2^2 (95th percentile confidence interval: 128 671–373 359), greater than that of the Congo basin, but around 30% smaller than a recent model-derived estimate of peatland area across Amazonia. The model performs relatively well against point observations but spatial gaps in the ground reference dataset mean that model uncertainty remains high, particularly in parts of Brazil and Bolivia. For example, we predict significant peatland areas in northern Peru with relatively high confidence, while peatland areas in the Rio Negro basin and adjacent south-western Orinoco basin which have previously been predicted to hold Campinarana or white sand forests, are predicted with greater uncertainty. Similarly, we predict large areas of peatlands in Bolivia, surprisingly given the strong climatic seasonality found over most of the country. Very little field data exists with which to quantitatively assess the accuracy of our map in these regions. Data gaps such as these should be a high priority for new field sampling. This new map can facilitate future research into the vulnerability of peatlands to climate change and anthropogenic impacts, which is likely to vary spatially across the Amazon basin
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