Estrutura e composição florística de comunidades de plantas em relação à distância geográfica na Amazônia Oriental.

Ministério da Educação, Universidade Federal Rural da Amazônia, Secretaria de Estado de Desenvolvimento, Ciência e Tecnologia e Fundação Amazônia Paraense de Amparo à Pesquisa.Entender os padrões que podem explicar a alta riqueza e diversidade de espécies vegetais em florestas tropicais e como estas espécies estão distribuídas é ainda uma questão muito complexa e pouco estudada. Dois modelos são aplicados para explicar esses padrões em regiões tropicais: o Modelo Neutro e o Modelo de Nicho, o primeiro diz que distribuição de espécies está relacionada a processos estocásticos como dispersão, enquanto o segundo modelo prediz que distribuição de espécies é resultado de processos não aleatórios. Alguns estudos mostram que a riqueza de espécies, diversidade e composição florística diminuiu com a distância geográfica em regiões tropicais. O objetivo desta dissertação foi testar diferenças na riqueza, diversidade, composição de espécies e a estrutura de uma floresta ombrófila densa em relação à distância geográfica em seis platôs situados na Floresta Nacional Sacará-Taquera, município de Oriximiná, Pará. A partir de um banco de dados resultante de um inventário florístico realizado nos seis platôs, e usando parcelas distribuídas em todo o platô, foram escolhidos para esta dissertação três ou quatro grupos de parcelas localizadas no centro e nas extremidades de cada platô. O número de parcelas analisadas em cada platô variou de 18 a 22. A distância entre os platôs variou de 5,1 a 23,7 km. A riqueza total de espécies entre os platôs variou de 277 a 401, enquanto a riqueza de espécies raras variou de 63 a 113. O índice de diversidade de Shannon-Weaver variou entre 4,2 e 5,02. As dez espécies com maior densidade e freqüência variaram entre os seis platôs amostrados, com somente duas espécies comuns aos seis platôs com relação a esses parâmetros. A maioria das espécies apresentou baixa freqüência absoluta nas parcelas amostradas e baixa abundância, um padrão típico para a floresta Amazônica. As curvas acumulativas de novas espécies não exibiram tendência de assíntota nos seis platôs analisados, sendo esta uma tendência também mostrada pelos estimadores de riqueza. A estrutura diamétrica nos seis platôs exibiu uma curva logarítmica, caracterizada pela alta proporção de árvores nas primeiras classes de diâmetro. Houve variação significativa na riqueza total, número de espécies raras, diversidade e densidade entre os seis platôs analisados. Houve correlação significativa e negativa da similaridade de espécies em relação à distância geográfica entre platôs e dentro dos platôs. Estes resultados sugerem que a variação na composição de espécies entre os platôs analisados está relacionada à influência da distância geográfica. Em relação à baixa similaridade dentro e entre platôs analisados, recomendase que pelo menos uma parte de cada platô deva ser preservada a fim de termos uma complementaridade na composição de espécies da flora em escala regional.Understand the patters that explain the high species richness, diversity and plant distribution are still questions very complexes and little studied in the tropical regions. Two main models are applied to explain these patters in tropical regions: The Neutral and Niches models, in the former related that the species distribution results of the biotic parameters, while the second model report that species distribution are results of no random processes. Some studies have reported that species richness, diversity and floristic composition decreased with geographic distance in tropical regions. The object of this dissertation is test difference in the species richness, diversity, plant distribution and forest structure in a tropical forest in the oriental Amazonian in relation to geographic distance. This study was carried out in the six forest plateaus situated in the Saracá-Taquera National Forest in the Pará. The data analyzed in the study were obtained in a forestry inventory done in throughout the plateau using plots of 10 x 250 m. In the study were selected some plots situated in the center and edges of the plateaus. The number of plots analyzed at each plateau it varied from 18 to 22. The distance between the plateaus varied from 5.1 to 23.7 km. The number of plots used in each plateau varied from 18 to 22. The total species richness varied from 277 to 401 species and the number of rare species varied from 63 to 113 species. The total diversity index varied from 4.2 to 5.0 among the plateaus. The ten species with larger density and frequency varied among the six plateaus, with only two species common to the six plateaus with relationship the those parameters. The majority of species have low absolute frequency in the plots sampled and it lowers abundance, a normal pattern reported to tropical forests. The number of cumulative species in relation to sampled plots didn't have tendency of asymptote in the plateaus which is also an expected patterns to tropical forests and shows in the richness estimators used in the study. The distribution of tree in relation to diameter exhibited a log-normal curve, with high proportion of individuais in the first diameter classes. There is significantly variation in the species richness, diversity, density and number of rare species among the plateaus. There is a negative correlation between floristic composition and geographic distance within and between the plateaus. The results of this dissertation clearly shows that species richness, diversity and floristic composition varied among the plateaus, being the last parameters negative correlated with geographic distance corroborating the presented results done by others studies. Due to lower species richness obtained between the plateaus analyzed should recommended that part of the area of each plateaus be preserved

A vocação da Amazônia é florestal e a criação de novos estados pode levar ao aumento do desflorestamento na Amazônia brasileira

The state of Pará has a rich diversity of ecosystems. However, it is one of the states that the most contribute with the deforestation of Amazonian. Actually, 22% of the state was deforested. Currently, a new policy of occupation is being studied for the Amazonian, based on the creation of new states. The creation of new states can increase deforestation in the Amazonian, especially in regions where the agricultural frontier and minerals activities are intense such as the state of Para. This study compares the changes of the representativeness of protected areas and deforestation, considering the proposed of division of the Para in three new states. The creation of new states can lead to a reduction or elimination of the protected areas resulting in the increase of the deforestation. Another serious consequence of the creation of new states will be the extinction of the Ecological-Economic Zoning of Para, an important instrument of public policy. The creation of new states must be preceded by studies involving the evaluation of the environmental, social and economic variables. One of the most serious consequences if it is not taken into consideration is the creation of a legal vacuum that will be used to increase the pressure on natural resources of the Amazon.O Pará detém uma rica diversidade de ecossistemas. Contudo, é um dos Estados que mais contribuem para o desmatamento na Amazônia. Atualmente, 22% do Estado foram desflorestados. Uma nova política de ocupação está sendo estudada para a Amazônia, baseada na criação de novos Estados. A criação de novos Estados pode aumentar o desmatamento na Amazônia, especialmente em regiões onde a fronteira agropecuária e mineraria é intensa como no Pará. Este estudo compara as mudanças da representatividade das áreas protegidas e do desmatamento, considerando a proposta de divisão do Estado do Pará em três novos Estados. A criação dos novos Estados pode levar a uma diminuição ou mesmo eliminação de algumas unidades de conservação, o que terá como consequência direta o aumento do desmatamento. Outra consequência grave da criação de novos Estados será a extinção do Zoneamento Ecológico-Econômico do Pará, um importante instrumento de políticas públicas. A criação de novos Estados deve ser precedida de estudos que envolvam uma avaliação criteriosa dos impactos ambientais, sociais e econômicos. Umas das consequências mais graves se isso não for levado em consideração é a criação de um vácuo jurídico que será aproveitado para aumentar a pressão nos recursos naturais da Amazônia

Variation in stem mortality rates determines patterns of above-ground biomass in Amazonian forests: implications for dynamic global vegetation models

Understanding the processes that determine above-ground biomass (AGB) in Amazonian forests is important for predicting the sensitivity of these ecosystems to environmental change and for designing and evaluating dynamic global vegetation models (DGVMs). AGB is determined by inputs from woody productivity [woody net primary productivity (NPP)] and the rate at which carbon is lost through tree mortality. Here, we test whether two direct metrics of tree mortality (the absolute rate of woody biomass loss and the rate of stem mortality) and/or woody NPP, control variation in AGB among 167 plots in intact forest across Amazonia. We then compare these relationships and the observed variation in AGB and woody NPP with the predictions of four DGVMs. The observations show that stem mortality rates, rather than absolute rates of woody biomass loss, are the most important predictor of AGB, which is consistent with the importance of stand size structure for determining spatial variation in AGB. The relationship between stem mortality rates and AGB varies among different regions of Amazonia, indicating that variation in wood density and height/diameter relationships also influences AGB. In contrast to previous findings, we find that woody NPP is not correlated with stem mortality rates and is weakly positively correlated with AGB. Across the four models, basin-wide average AGB is similar to the mean of the observations. However, the models consistently overestimate woody NPP and poorly represent the spatial patterns of both AGB and woody NPP estimated using plot data. In marked contrast to the observations, DGVMs typically show strong positive relationships between woody NPP and AGB. Resolving these differences will require incorporating forest size structure, mechanistic models of stem mortality and variation in functional composition in DGVMs

Variation in stem mortality rates determines patterns of above-ground biomass in Amazonian forests: implications for dynamic global vegetation models

This is the final version of the article. Available from Wiley via the DOI in this record.Understanding the processes that determine above-ground biomass (AGB) in Amazonian forests is important for predicting the sensitivity of these ecosystems to environmental change and for designing and evaluating dynamic global vegetation models (DGVMs). AGB is determined by inputs from woody productivity [woody net primary productivity (NPP)] and the rate at which carbon is lost through tree mortality. Here, we test whether two direct metrics of tree mortality (the absolute rate of woody biomass loss and the rate of stem mortality) and/or woody NPP, control variation in AGB among 167 plots in intact forest across Amazonia. We then compare these relationships and the observed variation in AGB and woody NPP with the predictions of four DGVMs. The observations show that stem mortality rates, rather than absolute rates of woody biomass loss, are the most important predictor of AGB, which is consistent with the importance of stand size structure for determining spatial variation in AGB. The relationship between stem mortality rates and AGB varies among different regions of Amazonia, indicating that variation in wood density and height/diameter relationships also influences AGB. In contrast to previous findings, we find that woody NPP is not correlated with stem mortality rates and is weakly positively correlated with AGB. Across the four models, basin-wide average AGB is similar to the mean of the observations. However, the models consistently overestimate woody NPP and poorly represent the spatial patterns of both AGB and woody NPP estimated using plot data. In marked contrast to the observations, DGVMs typically show strong positive relationships between woody NPP and AGB. Resolving these differences will require incorporating forest size structure, mechanistic models of stem mortality and variation in functional composition in DGVMs.This paper is a product of the European Union's Seventh Framework Programme AMAZALERT project (282664). The field data used in this study have been generated by the RAINFOR network, which has been supported by a Gordon and Betty Moore Foundation grant, the European Union's Seventh Framework Programme projects 283080, ‘GEOCARBON’; and 282664, ‘AMAZALERT’; ERC grant ‘Tropical Forests in the Changing Earth System’), and Natural Environment Research Council (NERC) Urgency, Consortium and Standard Grants ‘AMAZONICA’ (NE/F005806/1), ‘TROBIT’ (NE/D005590/1) and ‘Niche Evolution of South American Trees’ (NE/I028122/1). Additional data were included from the Tropical Ecology Assessment and Monitoring (TEAM) Network – a collaboration between Conservation International, the Missouri Botanical Garden, the Smithsonian Institution and the Wildlife Conservation Society, and partly funded by these institutions, the Gordon and Betty Moore Foundation, and other donors. Fieldwork was also partially supported by Conselho Nacional de Desenvolvimento Científico e Tecnológico of Brazil (CNPq), project Programa de Pesquisas Ecológicas de Longa Duração (PELD-403725/2012-7). A.R. acknowledges funding from the Helmholtz Alliance ‘Remote Sensing and Earth System Dynamics’; L.P., M.P.C. E.A. and M.T. are partially funded by the EU FP7 project ‘ROBIN’ (283093), with co-funding for E.A. from the Dutch Ministry of Economic Affairs (KB-14-003-030); B.C. [was supported in part by the US DOE (BER) NGEE-Tropics project (subcontract to LANL). O.L.P. is supported by an ERC Advanced Grant and is a Royal Society-Wolfson Research Merit Award holder. P.M. acknowledges support from ARC grant FT110100457 and NERC grants NE/J011002/1, and T.R.B. acknowledges support from a Leverhulme Trust Research Fellowship

An estimate of the number of tropical tree species

The high species richness of tropical forests has long been recognized, yet there remains substantial uncertainty regarding the actual number of tropical tree species. Using a pantropical tree inventory database from closed canopy forests, consisting of 657,630 trees belonging to 11,371 species, we use a fitted value of Fisher’s alpha and an approximate pantropical stem total to estimate the minimum number of tropical forest tree species to fall between ∼40,000 and ∼53,000, i.e. at the high end of previous estimates. Contrary to common assumption, the Indo-Pacific region was found to be as species-rich as the Neotropics, with both regions having a minimum of ∼19,000–25,000 tree species. Continental Africa is relatively depauperate with a minimum of ∼4,500–6,000 tree species. Very few species are shared among the African, American, and the Indo-Pacific regions. We provide a methodological framework for estimating species richness in trees that may help refine species richness estimates of tree-dependent taxa

Autoantibodies against type I IFNs in patients with life-threatening COVID-19

Interindividual clinical variability in the course of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is vast. We report that at least 101 of 987 patients with life-threatening coronavirus disease 2019 (COVID-19) pneumonia had neutralizing immunoglobulin G (IgG) autoantibodies (auto-Abs) against interferon-w (IFN-w) (13 patients), against the 13 types of IFN-a (36), or against both (52) at the onset of critical disease; a few also had auto-Abs against the other three type I IFNs. The auto-Abs neutralize the ability of the corresponding type I IFNs to block SARS-CoV-2 infection in vitro. These auto-Abs were not found in 663 individuals with asymptomatic or mild SARS-CoV-2 infection and were present in only 4 of 1227 healthy individuals. Patients with auto-Abs were aged 25 to 87 years and 95 of the 101 were men. A B cell autoimmune phenocopy of inborn errors of type I IFN immunity accounts for life-threatening COVID-19 pneumonia in at least 2.6% of women and 12.5% of men

Phylogenetic classification of the world's tropical forests

Knowledge about the biogeographic affinities of the world’s tropical forests helps to better understand regional differences in forest structure, diversity, composition, and dynamics. Such understanding will enable anticipation of region-specific responses to global environmental change. Modern phylogenies, in combination with broad coverage of species inventory data, now allow for global biogeographic analyses that take species evolutionary distance into account. Here we present a classification of the world’s tropical forests based on their phylogenetic similarity. We identify five principal floristic regions and their floristic relationships: (i) Indo-Pacific, (ii) Subtropical, (iii) African, (iv) American, and (v) Dry forests. Our results do not support the traditional neo- versus paleotropical forest division but instead separate the combined American and African forests from their Indo-Pacific counterparts. We also find indications for the existence of a global dry forest region, with representatives in America, Africa, Madagascar, and India. Additionally, a northern-hemisphere Subtropical forest region was identified with representatives in Asia and America, providing support for a link between Asian and American northern-hemisphere forests.</p