Papers by Marcos Silveira
Global Change Biology, 2018
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Nature Ecology & Evolution, 2018
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Nature Ecology & Evolution, 2018
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Scientific reports, Jan 17, 2018
Species distribution models (SDMs) are widely used in ecology and conservation. Presence-only SDM... more Species distribution models (SDMs) are widely used in ecology and conservation. Presence-only SDMs such as MaxEnt frequently use natural history collections (NHCs) as occurrence data, given their huge numbers and accessibility. NHCs are often spatially biased which may generate inaccuracies in SDMs. Here, we test how the distribution of NHCs and MaxEnt predictions relates to a spatial abundance model, based on a large plot dataset for Amazonian tree species, using inverse distance weighting (IDW). We also propose a new pipeline to deal with inconsistencies in NHCs and to limit the area of occupancy of the species. We found a significant but weak positive relationship between the distribution of NHCs and IDW for 66% of the species. The relationship between SDMs and IDW was also significant but weakly positive for 95% of the species, and sensitivity for both analyses was high. Furthermore, the pipeline removed half of the NHCs records. Presence-only SDM applications should consider th...
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Scientific reports, Jan 17, 2017
Tropical forests are global centres of biodiversity and carbon storage. Many tropical countries a... more Tropical forests are global centres of biodiversity and carbon storage. Many tropical countries aspire to protect forest to fulfil biodiversity and climate mitigation policy targets, but the conservation strategies needed to achieve these two functions depend critically on the tropical forest tree diversity-carbon storage relationship. Assessing this relationship is challenging due to the scarcity of inventories where carbon stocks in aboveground biomass and species identifications have been simultaneously and robustly quantified. Here, we compile a unique pan-tropical dataset of 360 plots located in structurally intact old-growth closed-canopy forest, surveyed using standardised methods, allowing a multi-scale evaluation of diversity-carbon relationships in tropical forests. Diversity-carbon relationships among all plots at 1 ha scale across the tropics are absent, and within continents are either weak (Asia) or absent (Amazonia, Africa). A weak positive relationship is detectable ...
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Proceedings. Biological sciences, Dec 14, 2016
Lineages tend to retain ecological characteristics of their ancestors through time. However, for ... more Lineages tend to retain ecological characteristics of their ancestors through time. However, for some traits, selection during evolutionary history may have also played a role in determining trait values. To address the relative importance of these processes requires large-scale quantification of traits and evolutionary relationships among species. The Amazonian tree flora comprises a high diversity of angiosperm lineages and species with widely differing life-history characteristics, providing an excellent system to investigate the combined influences of evolutionary heritage and selection in determining trait variation. We used trait data related to the major axes of life-history variation among tropical trees (e.g. growth and mortality rates) from 577 inventory plots in closed-canopy forest, mapped onto a phylogenetic hypothesis spanning more than 300 genera including all major angiosperm clades to test for evolutionary constraints on traits. We found significant phylogenetic sig...
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Global Change Biology, 2016
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Science Advances, 2015
Analyses of forest loss and protected areas suggest that 36 to 57% of Amazonian tree flora may qu... more Analyses of forest loss and protected areas suggest that 36 to 57% of Amazonian tree flora may qualify as “globally threatened.”
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Scientia Forestalis/Forest Sciences
We show that in a bamboo-dominated forest in Southwestern Amazonia the tree mortality rate does n... more We show that in a bamboo-dominated forest in Southwestern Amazonia the tree mortality rate does not differ between the forest edge and the interior, even though bamboo abundance is higher closer to the edge. We tested whether bamboo abundance affects mortality rate in three areas within a forest fragment of ca. 1,166 ha. We estimated mortality rate for trees with > 10 cm dbh during 1.8 years. Bamboo abundance was approximately three times higher on the edge (3394 ± 1121 culms ha-1) than in the interior of the forest (1123 ± 754 stems ha-1). The annual mortality rate did not differ significantly between edge (3.8 ± 2.6 % y-1) and interior (3.6 ± 2.6 % y-1), but the main modes of tree mortality, 'dead standing' and 'broken,' differed significantly between edge and interior. Tree mortality was higher for smaller trees (10-30 dbh) and did not differ between forest edge and interior. However, bamboo abundance explained 23% of tree mortality rate at the edge, even thoug...
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Nature, 2015
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Phytotaxa, 2014
Vascular epiphytes are common in tropical forests and represent a considerable part of the biodiv... more Vascular epiphytes are common in tropical forests and represent a considerable part of the biodiversity in Southwestern Amazonia. The aim of this study was to determine the floristic composition, patterns of species richness, and geographical distribution and knowledge gaps (collection effort) of the epiphytic vascular flora of the Brazilian State of Acre. We analyzed the database of the Flora of Acre and found a total of 331 species and 32 families of angiosperms and ferns. Almost half of the epiphytic flora of Acre (48% of species) occurs only in Northern Brazil. Of the total species, 56% are restricted to Amazonia. The distribution of the number of collections of epiphytes is concentrated in a few locations in the state and there is a positive correlation between the number of collections of epiphytes and the general index of collection density. The low and unequal sampling effort of epiphytes across the State, the high proportion of specimens identified at best to genus, and the...
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Geoscientific Model Development, 2014
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Phytotaxa, 2014
Even though it is well known that the flora of Amazonia is severely under-documented, botanical r... more Even though it is well known that the flora of Amazonia is severely under-documented, botanical research in the region has been stagnant for the past two decades or more. An exception to this trend has been the international collaboration in the state of Acre, Brazil. The objective of this study was to assess botanical progress in Southwestern Amazonia, specifically the evolution of our knowledge of the flora of the state of Acre five years after production of the first catalogue of its flora. Between 2006-2011, the Acre data-base recorded 2,110 determinations, and among these were 347 new records for Acre, representing an increase of 8.6% in the known flora, which as of 2011 comprised 4351 species. Of the new records, 6.6% (23) were new records for Brazil and 14.4% (50) represented genera new to Acre. The new records comprised 322 species of vascular plants and 22 of non-vascular plants. The most significant finding was that one of every six identifications was a new record f...
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Emu, 2003
Large-scale patterns of Amazonian biodiversity have until now been obscured by a sparse and scatt... more Large-scale patterns of Amazonian biodiversity have until now been obscured by a sparse and scattered inventory record. Here we present the first comprehensive spatial model of tree a-diversity and tree density in Amazonian rainforests, based on the largest-yet compilation of forest inventories and bolstered by a spatial interpolation technique that allows us to estimate diversity and density in areas that have never been inventoried. These data were then compared to continent-wide patterns of rainfall seasonality.We find that dry season length, while only weakly correlated with average tree a-diversity, is a strong predictor of tree density and of maximum tree a-diversity. The most diverse forests for any given DSL are concentrated in a narrow latitudinal band just south of the equator, while the least diverse forests for any given DSL are found in the Guayana Shield and Amazonian Bolivia. Denser forests are more diverse than sparser forests, even when we used a measure of diversity that corrects for sample size. We propose that rainfall seasonality regulates tree a-diversity and tree density by affecting shade tolerance and subsequently the number of different functional types of trees that can persist in an area.
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Biogeosciences Discussions, 2009
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Ecology and Society, 2014
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Catálogo de plantas e fungos do Brasil - Vol. 2, 2010
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Biota Neotropica, 2013
Forest fragmentation affects the structure and dynamics of plant communities, leading to biodiver... more Forest fragmentation affects the structure and dynamics of plant communities, leading to biodiversity loss in forest remnants. In this paper we show that in a bamboo (Guadua weberbaueri Pilger) dominated forest fragment in southwestern Amazonia edge effect may be confounded by bamboo effect, which also occur inside the forest. We measured growth, mortality and, recruitment rate of trees with DBH ≥ 10 cm, in a fragment of bamboo dominated open forest in southwestern Amazonia, state of Acre, Brazil, in 15 plots at the forest edge and 15 plots inside the forest fragment, 500 m away from the border. Time interval between censuses was 1.8 years. The average diameter growth rate differed significantly between edge (3.82 ± 0.10 mm a-1) and interior (2.39 ± 0.18 mm a-1); but there were no differences in annual mortality rate (edge = 3.8 ± 2.5 % a-1 CV = 65.7%; interior = 3.6 ± 2.6% a-1 CV = 72.2%) or in annual recruitment rate (edge = 7.1 ± 3.2% a-1 CV = 45%; interior = 8.9 ± 7.9% a-1 CV = ...
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Science, 2013
Introduction Recent decades have seen a major international effort to inventory tree communities ... more Introduction Recent decades have seen a major international effort to inventory tree communities in the Amazon Basin and Guiana Shield (Amazonia), but the vast extent and record diversity of these forests have hampered an understanding of basinwide patterns. To overcome this obstacle, we compiled and standardized species-level data on more than half a million trees in 1170 plots sampling all major lowland forest types to explore patterns of commonness, rarity, and richness. Methods The ~6-million-km 2 Amazonian lowlands were divided into 1° cells, and mean tree density was estimated for each cell by using a loess regression model that included no environmental data but had its basis exclusively in the geographic location of tree plots. A similar model, allied with a bootstrapping exercise to quantify sampling error, was used to generate estimated Amazon-wide abundances of the 4962 valid species in the data set. We estimated the total number of tree species in the Amazon by fitting t...
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Plant Ecology & Diversity, 2013
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Papers by Marcos Silveira