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Featured researches published by D. F. Calheiros.


Hydrobiologia | 2000

Flood pulse influence on phytoplankton communities of the south Pantanal floodplain, Brazil

Márcia Divina de Oliveira; D. F. Calheiros

Four sites situated on the Pantanal floodplain (Paraguay River and floodplain) were sampled throughout the annual cycle, mainly during the rising water period, with the aim of evaluating the effects of the flood pulse on the composition and population densities of the phytoplanktonic communities. Comprehensive water chemistry data were collected. Eighty-two taxa were found, numerically dominated by Chlorophyceae (23 taxa). Cryptophyceae (principally Cryptomonas brasiliensis) occurred in all samples, and were responsible for 47–58% of the phytoplankton abundance in the studied area. Highest phytoplanktonic population density was at the rising water period, when the limnological changes are most marked as the river water first enters into contact with the floodplain. During this period, when intense decomposition occurs, the Cryptophyceae decreased and the Euglenophyceae increased, except at site 1 (Castelo Lake), where this group were more stable during the year, representing 35–56% of the phytoplankton. In the falling water period (September and October), the phytoplankton was also represented by Bacillariophyceae and Cyanophyceae. In the Pantanal, the great abundance and sometimes dominance of Cryptophyceae, may be due largely to adverse conditions for the development of other groups; the former are adapted to low availability of dissolved nutrients, and high water transparency, such conditions prevailing during the high water period.


Biological Invasions | 2011

Abiotic factors controlling the establishment and abundance of the invasive golden mussel Limnoperna fortunei

Márcia Cristina de Sena Oliveira; D. F. Calheiros; Claudia Maria Jacobi; Stephen K. Hamilton

Limnoperna fortunei (Bivalvia, Mytilidae), a freshwater bivalve native to Southern Asia, has been an invasive species in South America since 1991. It spread upstream in the La Plata basin reaching the Paraguay River in the vicinity of the Pantanal wetland, Brazil, around 1998. The role of abiotic factors in controlling establishment and abundance of this species is not well known, making projections of its risk of further spread difficult. This study evaluates the importance of abiotic factors to L. fortunei populations established in rivers of the Pantanal, focusing on larval and juvenile densities and taking advantage of a wide range of seasonal variability in water temperature, flow, dissolved oxygen, and suspended material. Temperature, river stage (influencing several water characteristics) and water velocity are the main variables related to the larval and juvenile densities. In the Pantanal, environmental variables vary over a broader range compared with other South American locations, subjecting L. fortunei to oxygen depletion, low calcium, low pH, and high water velocity and suspended solids, associated with low chlorophyll a concentrations. The combined effect of several of these conditions may explain the relatively low densities in some Pantanal sites. However, they probably will not prevent the persistence of populations in the Pantanal and the eventual establishment of viable populations in upriver systems connected to the Pantanal. These results are pertinent not only to this species but also to other aquatic invasive invertebrates whose expansion may be limited by thermal extremes, episodic oxygen depletion, and waters that are too dilute or acidic for optimal biocalcification.


Journal of Environmental Science and Health Part B-pesticides Food Contaminants and Agricultural Wastes | 2008

Pesticide residues in river sediments from the Pantanal Wetland, Brazil.

Kelber Miranda; Marcelo Luiz Ferreira Cunha; Eliana Freire Gaspar de Carvalho Dores; D. F. Calheiros

Sediment samples from 25 sites in 17 rivers of the Pantanal (Brazil) were analyzed with the objective of evaluating pesticide contamination in sediments. Samples were extracted with an acetone, ethylacetate, and water mixture 2:2:1 (v/v/v). The extract was purified by flash chromatography with aluminum oxide and florisil. A multiresidue gas chromatography-mass spectrometry method was applied to monitor 23 pesticides of different chemical classes (organochlorine, organophosphorus, triazines, anilides and pyrethroids) with some of their degradation products. Compounds identified in sediment samples included λ -cyhalothrin (1.0 to 5.0 μ g kg− 1), p,p′-DDT (3.6 μ g kg− 1), deltamethrin (20.0 μ g kg− 1) and permethrin (1.0 to 7.0 μ g kg− 1).


Brazilian Journal of Biology | 2010

Modeling the potential distribution of the invasive golden mussel Limnoperna fortunei in the Upper Paraguay River system using limnological variables

Oliveira; Stephen K. Hamilton; D. F. Calheiros; Claudia Maria Jacobi; Ro Latini

The invasive golden mussel, Limnoperna fortunei (Dunker, 1857), was introduced into the La Plata River estuary and quickly expanded upstream to the North, into the Paraguay and Paraná rivers. An ecological niche modeling approach, based on limnological variables, was used to predict the expansion of the golden mussel in the Paraguay River and its tributaries. We used three approaches to predict the geographic distribution: 1) the spatial distribution of calcium concentration and the saturation index for calcium carbonate (calcite); 2) the Genetic Algorithm for Rule-Set Production (GARP) model; and the 3) Maximum Entropy Method (Maxent) model. Other limnological variables such as temperature, dissolved oxygen, pH, and Total Suspended Solids (TSS) were used in the latter two cases. Important tributaries of the Paraguay River such as the Cuiabá and Miranda/Aquidauana rivers exhibit high risk of invasion, while lower risk was observed in the chemically dilute waters of the middle basin where shell calcification may be limited by low calcium concentrations and carbonate mineral undersaturation.


Check List | 2008

Segesta riograndensis , Ephemeroptera, Leptophlebiidae, Atalophlebiinae: first record from state of Mato Grosso do Sul, western Brazil

Karina O. Righi-Cavallaro; Ana Emilia Siegloch; D. F. Calheiros; Domingos Sávio Barbosa

The mayfly Segesta riograndensis (Ephemeroptera: Leptophlebiidae) was recently described by Siegloch et al. (2006) based on larvae from southern Brazil, municipality of Independencia, northwest from state of Rio Grande do Sul. The larvae can be distinguished from other genera of Atalophlebiinae by the following combination of characters: clypeus slightly divergent with sinuous margin; labrum with shallow emargination and three nonprominent denticles; maxillary palpi very large and curved with setae in varied combinations; labial palpi very long and curved, with long setae (Figure 1A-B); paraglossae wider than long; abdominal posterolateral spines gradually longer posteriorly. Here we are extending the range distribution of S. riograndensis in 850 kilometers to the northwest Rio Grande do Sul to state of Mato Grosso do Sul (Figure 2).


Journal of Environmental Management | 2017

A fuzzy logic-based tool to assess beef cattle ranching sustainability in complex environmental systems

Sandra Aparecida Santos; Helano Póvoas de Lima; S. M. F. S. Massruhá; Urbano Gomes Pinto de Abreu; Walfrido Moraes Tomas; Suzana Maria Salis; E. L. Cardoso; Márcia Divina de Oliveira; M. T. S. Soares; Antônio dos Santos; L. O. F. Oliveira; D. F. Calheiros; S. M. A. Crispim; B. M. A. Soriano; Christiane O.G. Amâncio; Alessandro Pacheco Nunes; L. A. Pellegrin

One of the most relevant issues in discussion worldwide nowadays is the concept of sustainability. However, sustainability assessment is a difficult task due to the complexity of factors involved in the natural world added to the human interference. In order to assess the sustainability of beef ranching in complex and uncertain tropical environment systems this paper describes a decision support system based on fuzzy rule-approach, the Sustainable Pantanal Ranch (SPR). This tool was built by a set of measurements and indicators integrated by fuzzy logic to evaluate the attributes of the three dimensions of sustainability. Indicators and decision rules, as well as scenario evaluations, were obtained from workshops involving multi-disciplinary team of experts. A Fuzzy Rule-Based System (FRBS) was developed to each attribute, dimension and general index. The essential parts of the FRBS are the knowledge database, rules and the inference engine. The FuzzyGen and WebFuzzy tools were developed to support the FRBS and both showed efficiency and low cost for digital applications. The results of each attribute, dimension and index were presented as radar graphs, showing the individual value (0-10) of each indicator. In the validation process using the WebFuzzy, different combinations of indicators were made for each attribute index to show the corresponding output, and which confirm the feasibility and usability of the tool.


Verhandlungen - Internationale Vereinigung für theoretische und angewandte Limnologie | 1998

Limnological conditions associated with natural fish kills in the Pantanal Wetland of Brazil

D. F. Calheiros; Stephen K. Hamilton


Wetlands | 2010

Oxygen depletion events control the invasive golden mussel (Limnoperna fortunei) in a tropical floodplain.

Márcia Cristina de Sena Oliveira; Stephen K. Hamilton; D. F. Calheiros; Claudia Maria Jacobi


Archive | 2013

Mapeamento e descrição das áreas de ocorrência dos eventos de decoada no Pantanal.

M. D. de Oliveira; D. F. Calheiros; Carlos Roberto Padovani


Revista Brasileira de Agroecologia | 2009

Contaminação por agrotóxicos na bacia do rio Miranda, Pantanal (MS)

Eliana Freire Gaspar de Carvalho Dores; D. F. Calheiros

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M. T. S. Soares

Empresa Brasileira de Pesquisa Agropecuária

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E. L. Cardoso

Empresa Brasileira de Pesquisa Agropecuária

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S. A. Santos

Federal University of Bahia

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S. M. A. Crispim

Empresa Brasileira de Pesquisa Agropecuária

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S. M. F. S. Massruhá

Empresa Brasileira de Pesquisa Agropecuária

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Walfrido Moraes Tomas

Empresa Brasileira de Pesquisa Agropecuária

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B. M. A. Soriano

Empresa Brasileira de Pesquisa Agropecuária

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Claudia Maria Jacobi

Universidade Federal de Minas Gerais

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