LEVANTAMENTO DAS ESPÉCIES ARBÓREAS DA REGIÃO DE MANAUS-AMAZONAS

Na Amazônia, a cidade de Manaus e seus arredo­res constituem uma das regiões mais estudadas sob o aspecto botânico e ecológico, fato que pode ser facil­mente comprovado através dos inúmeros trabalhos já publicados. Porém, as informações obtidas encontram­ se de maneira muito dispersa, dificultando desde uma consulta elementar até uma análise mais profunda sobre a ocorrência de novas espécies de árvores. A partir deste fato,julgou-se interessante fazer um levantamen­to dos diversos inventários realizados, entre outros informes, num raio de 200 km de Manaus, a fim de possibilitar uma amostragem ampla quanto ao número de espécies de árvores e suas ocorrências nos diferen­tes tipos de vegetação ou ecossistemas presentes na região. Os dados obtidos neste levantamento de 12 trabalhos são apresentados através de tabelas compa­rativas, com localização, área amostrada,tipo de vege­ tação, DAP mínimo utilizado e números de famílias, gêneros e espécies encontrados. A comparação florís­tica entre famílias, gêneros e espécies indica como sendo a família Sapotaceae a maior em número de espécies (60),o Protium (Burseraceae), o maior gênero em número de espécies (24), e o cardeiro Scleronemamicranthum, Bombacaceae),a espécie com maior ocor­rência em número de áreas e ambientes (8 localidades)

Habitat amount hypothesis and passive sampling explain mammal species composition in Amazonian river islands

Nested structures of species assemblages have been frequently associated with patch size and isolation, leading to the conclusion that colonization–extinction dynamics drives nestedness. The ‘passive sampling’ model states that the regional abundance of species randomly determines their occurrence in patches. The ‘habitat amount hypothesis’ also challenges patch size and isolation effects, arguing that they occur because of a ‘sample area effect’. Here, we (a) ask whether the structure of the mammal assemblages of fluvial islands shows a nested pattern, (b) test whether species’ regional abundance predicts species’ occurrence on islands, and (c) ask whether habitat amount in the landscape and matrix resistance to biological flow predict the islands’ species composition. We quantified nestedness and tested its significance using null models. We used a regression model to analyze whether a species’ relative regional abundance predicts its incidence on islands. We accessed islands’ species composition by an NMDS ordination and used multiple regression to evaluate how species composition responds to habitat amount and matrix resistance. The degree of nestedness did not differ from that expected by the passive sampling hypothesis. Likewise, species’ regional abundance predicted its occurrence on islands. Habitat amount successfully predicted the species composition on islands, whereas matrix resistance did not. We suggest the application of habitat amount hypothesis for predicting species composition in other patchy systems. Although the island biogeography perspective has dominated the literature, we suggest that the passive sampling perspective is more appropriate for explaining the assemblages’ structure in this and other non-equilibrium patch systems. Abstract in Portuguese is available with online material. © 2019 The Association for Tropical Biology and Conservatio

Observations on flower visitors to Bertholletia excelsa H.B.K. and Couratari tenuicarpa A.C. Sm. (Lecythidaceae)

Bees visiting flowers of Bertholletia excelsa. (Brazil Nut tree) and Couratari tenuicarpa were collected, their behavior described and the pollen found clinging to their dorsal thorax and stored on their legs was identified. Female bees of Xylocopa frontalis(Olivier) and males of Eulaema mocsaryi (Friese) are apparently effective pollinators of Couratari in igapó near Manaus. Female bees of Euplusia seabrai Moure in litt., Epicharis umbraculata (Fabricius), Epicharis rustica (Olivier) and Eulaema nigrita(Lepeletier), as well as male bees of Eulaema cingulata(Fabricius) and Eulaema nigrita are apparently effective pollinators of adult Brazil Nut trees in the Aleixo plantation near Manaus. Only large bees capable of uncurling the floral androecium can effectively pollinate Couratari or Bertholletia.Pollen analysis indicated that all bees captured carried pollen of the host tree in question and had been foraging on flowers of plant species common in secondary growth. Secondary growth near the Aleixo plantation supports a bee guild which appeared to effectively pollinate almost every flower on the Brazil Nut tree studied. Proximity to primary forest (and to those Euglossine bee species which occur only in primary forest) therefore does not appear to be necessary for pollination of Brazil Nut trees.In the Aleixo plantation chronic low fruit set is probably due to some factor other than pollination. Since natural occurrences of Brazil Nut trees to the north and south of Manaus are associated with a higher soil fertility, low production at the Aleixo plantation may be due to deficiencies of the soil.Foram estudadas as abelhas que visitavam flores de Bertholletia excelsa H. B. K. (castanheira) e Couratai tenuicarpa A.C. Smith. Foi descrito o comportamento dessas abelhas e identificados os grãos de pólen aderido à parte dorsal do tórax e nas patas. As abelhas femininas de Xylocopa frontalis (Olivier) e masculinas de Eulaema moesaryi (Friese) observadas em igapó próximo de Manaus, são aparentemente polinizadores de Couratari. As abelhas femininas de Euplusia seabrai Moure in litt., Epicharis umbraculata (Fabricius), Epicharis rustica(Olivier) and Eulaema nigrita (Lepeletier), bem como as abelhas masculinas de Eulaema cingulata (Fabricius) e Eulaema nigrita sao aparentemente polinizadores da castanheira estudada em uma plantação na Estrada do Aleixo, próximo a Manaus. Apenas as abelhas maiores, capazes de desenrolar o androceu floral, podem polinizar Couratari e Bertholletia.A análise polínica indicou que todas as abelhas capturadas transportavam pólen de Bertholletia ou Couratari. Os outros grãos de pólen encontrados nas abelhas provém de plantas de capoeira. Observamos que estas abelhas provém de plantas de capoeira. Observamos que estas abelhas comuns em capoeira visitaram praticamente todas as flores da castanheira permitindo assim, constatar que a presença de mata primária (e aquelas espécies de abelhas Euglossine restritas a mata primária) não é necessária para a polinização da castanheira.A baixa produção de frutos na plantação do Aleixo deve ser atribuida a outros fatores, e não a polinização. Uma vez que as ocorrências naturais de castanheiras na região estão associadas com melhores condições edáficas, essa baixa produção de frutos na plantação do Aleixo pode ser devido as deficiências do solo

Projeto Flora Amazônica: eight years of binational botanical expeditions

A review of the history and results of the first eight years of fieldwork of Projeto Flora Amazônica is given. This binational plant collecting program, sponsored by the Conselho Nacional de Desenvolvimento Científico e Tecnológico and the National Science Foundation, has mounted 25 expeditions to many parts of Brazilian Amazonia. Expeditions have visited both areas threatened with destruction of the forest and remote areas previously unknown botanically. The results have included the collection of 32,976 members of vascular plants, 16, 482 of cryptogams, as well as quantitative inventory of 18.67 hectares of forest with the collection of 7,294*** numbers of sterile vouncher collections. The non-inventory collections have been made in replicate sets of 10-13 where possible and divided equally between Brazilian and U.S. institutions. To date, 55 botanists from many different institutions and with many different specialities have taken part with 36 different Brazilian botanists. The resulting herbarioum material is just beginning to be worked up and many nem species have been collected as well as many interesting range extensions and extra material of many rare species.Apresentamos um histórico e resultados dos primeiros oito anos de pesquisas do Projeto Flora Amazônica. Este programa binacional de coleta de plantas amazônicas patrocinado pelo CNPq e o National Science Foundation, possibilitou 25expedições em numerosas regiões da Amazônia brasileira. As expedições visitaram tanto áreas ameaçadas de desmatamento extensivo, como áreas longínquas pouco conhecidas botanicamente. Os resultados incluem a coleta de 32.976 números de plantas superiores, 16.482 criptó_ gamas e inventário quantitativo de 18,67 hectares de floresta, envolvendo a coleta de 7.294 exsicatas estéreis. As coletas feitas para herborização foram realizadas com 10 a 13 duplicatas, quando possível, e divididas igualmente entre instituições brasileiras e dos EUA. Até o final de 1984 tomaram parte 55botânicos convidados de diversas instituições estrangeiras em diversas áreas, de especialização, junto com 36 botânicos brasileiros. 0 material coletado está na fase inicial de identificação e estudo pelos especialistas. Entretanto, muitas espécies novas e novos registros geográficos já foram reconhecidos, e novo material de espécies tidas como raras está sendo incorporado nos acervos dos herbários

Life cycle of bamboo in the southwestern Amazon and its relation to fire events

Bamboo-dominated forests comprise 1 % of the world's forests and 3 % of the Amazon forests. The Guadua spp. bamboos that dominate the southwest Amazon are semelparous; thus flowering and fruiting occur once in a lifetime before death. These events occur in massive spatially organized patches every 28 years and produce huge quantities of necromass. The bamboo-fire hypothesis argues that increased dry fuel after die-off enhances fire probability, creating opportunities that favor bamboo growth. In this study, our aim is to map the bamboo-dominated forests and test the bamboo-fire hypothesis using satellite imagery. Specifically, we developed and validated a method to map the bamboo die-off and its spatial distribution using satellite-derived reflectance time series from the Moderate Resolution Imaging Spectroradiometer (MODIS) and explored the bamboo-fire hypothesis by evaluating the relationship between bamboo die-off and fires detected by the MODIS thermal anomalies product in the southwest Amazon. Our findings show that the near-infrared (NIR) is the most sensitive spectral interval to characterize bamboo growth and cohort age. Automatic detection of historical bamboo die-off achieved an accuracy above 79 %. We mapped and estimated 15.5 million ha of bamboo-dominated forests in the region. The bamboo-fire hypothesis was not supported because only a small fraction of bamboo areas burned during the analysis timescale, and, in general, bamboo did not show higher fire probability after the die-off. Nonetheless, fire occurrence was 45 % higher in dead than live bamboo in drought years, associated with ignition sources from land use, suggesting a bamboo-human-fire association. Although our findings show that the observed fire was not sufficient to drive bamboo dominance, the increased fire occurrence in dead bamboo in drought years may contribute to the maintenance of bamboo and potential expansion into adjacent bamboo-free forests. Fire can even bring deadly consequences to these adjacent forests under climate change effects. © 2018 Author(s)

Reducing natural vegetation loss in Amazonia critically depends on the formal recognition of indigenous lands

The Brazilian Amazon contains the world's largest tract of tropical forest, about 22 % of which is within demarcated indigenous territories. Formal governmental recognition of these traditional territories is often a critical deterrent to deforestation, but the relative conservation performance of Indigenous Lands (ILs) under different legal categories and geographic contexts remains poorly understood. We used 30-m resolution Landsat satellite imagery to quantitatively assess the land cover status and annual rates of natural vegetation loss between 1985 and 2020 for 381 indigenous territories amounting to ~115 million hectares. Using a comprehensive set of environmental and socio-economic covariates and a mixed-modelling approach, we found that all stages of formal IL recognition consistently inhibit natural vegetation loss throughout the Brazilian Amazon compared to adjacent unprotected areas. Formal physical demarcation and distance from roads were the main proximate drivers of avoided natural vegetation loss inside ILs. Forest loss associated with road access is substantially curbed by ILs, showing the importance of frontier expansion when assessing indigenous reserve performance in counteracting natural vegetation loss. Because loss of natural forest and savannah areas associated with agribusiness frontiers and infrastructure projects are likely to intensify, the importance of ecosystem services provided by ILs is expected to increase across the Brazilian Amazon. Cultural profile and human density exerted no impacts on IL effectiveness in precluding natural vegetation loss. Given widespread encroachment of timber extraction and agribusiness, formal recognition of indigenous territories is a critical factor in decelerating primary habitat conversion across the Amazon

Conservation and management implications of nest-site selection of the sympatric crocodilians Melanosuchus niger and Caiman crocodilus in Central Amazonia, Brazil

Management of crocodilians is often based on source-sink dynamics, protecting breeding habitat and concentrating hunting in other areas. Nest distributions shed light on habitat use by breeding populations, which might be used as a basis for monitoring and management. The heterogeneous spatial distribution of Melanosuchus niger and Caiman crocodilus in Amazonia has been suggested to reflect past hunting pressure, often underestimating the natural ecological peculiarities of these species. Ground nest surveys combined with satellite imagery allowed us to evaluate whether nest-site use by M. niger and C. crocodilus reflects environmental constraints or is a result of hunting pressure. Our results indicate that there is little evidence that hunting pressure shapes nest-site use of these species in our study areas. M. niger nests mainly on the shores of stable, temporally impounded floodplain lakes isolated from the early stages of the annual rising water of main rivers. This behavior facilitates the identification of suitable nesting sites using moderate-resolution remote-sensing tools and should guide monitoring efforts and the protection of these areas. In contrast, C. crocodilus is a generalist species, able to nest hundreds of meters inside the forest far from permanent water. This makes the occurrence and distribution of nesting-sites unpredictable using Landsat images. Although nests of this species can be found around lakes where nests of M. niger also occur, the protection of these sites might help to preserve only a small portion of C. crocodilus nesting females. Thus, conservation strategies for C. crocodilus should probably be based on different approaches. © 2010 Elsevier Ltd

CCR5AS lncRNA variation differentially regulates CCR5, influencing HIV disease outcome.

Multiple genome-wide studies have identified associations between outcome of human immunodeficiency virus (HIV) infection and polymorphisms in and around the gene encoding the HIV co-receptor CCR5, but the functional basis for the strongest of these associations, rs1015164A/G, is unknown. We found that rs1015164 marks variation in an activating transcription factor 1 binding site that controls expression of the antisense long noncoding RNA (lncRNA) CCR5AS. Knockdown or enhancement of CCR5AS expression resulted in a corresponding change in CCR5 expression on CD4+ T cells. CCR5AS interfered with interactions between the RNA-binding protein Raly and the CCR5 3' untranslated region, protecting CCR5 messenger RNA from Raly-mediated degradation. Reduction in CCR5 expression through inhibition of CCR5AS diminished infection of CD4+ T cells with CCR5-tropic HIV in vitro. These data represent a rare determination of the functional importance of a genome-wide disease association where expression of a lncRNA affects HIV infection and disease progression

Bamboo-Dominated Forests of the Southwest Amazon: Detection, Spatial Extent, Life Cycle Length and Flowering Waves

We map the extent, infer the life-cycle length and describe spatial and temporal patterns of flowering of sarmentose bamboos (Guadua spp) in upland forests of the southwest Amazon. We first examine the spectra and the spectral separation of forests with different bamboo life stages. False-color composites from orbital sensors going back to 1975 are capable of distinguishing life stages. These woody bamboos flower produce massive quantities of seeds and then die. Life stage is synchronized, forming a single cohort within each population. Bamboo dominates at least 161,500 km2 of forest, coincident with an area of recent or ongoing tectonic uplift, rapid mechanical erosion and poorly drained soils rich in exchangeable cations. Each bamboo population is confined to a single spatially continuous patch or to a core patch with small outliers. Using spatial congruence between pairs of mature-stage maps from different years, we estimate an average life cycle of 27-28 y. It is now possible to predict exactly where and approximately when new bamboo mortality events will occur. We also map 74 bamboo populations that flowered between 2001 and 2008 over the entire domain of bamboo-dominated forest. Population size averaged 330 km2. Flowering events of these populations are temporally and/or spatially separated, restricting or preventing gene exchange. Nonetheless, adjacent populations flower closer in time than expected by chance, forming flowering waves. This may be a consequence of allochronic divergence from fewer ancestral populations and suggests a long history of widespread bamboo in the southwest Amazon. © 2013 Carvalho et al