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| Registros recuperados: 214 | |
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| Martins,Rodrigo Silvestre; Juanicó,Marcelo. |
| ABSTRACT The biology and ecology of southwestern Atlantic loliginid squids have been intensively researched in the last few decades, mostly off the Brazilian southern coast. However, information gathered by scientific research cruisers, either past or recent, is limited. Three species of loliginid squids - the warm-tempered Doryteuthis sanpaulensis (Brakoniecki, 1984), plus the tropical D. pleii (Blainville, 1823) and Lolliguncula brevis (Blainville, 1823) - were sampled along 16 degrees of latitude on the southwestern Atlantic (22-38°S). The samples were obtained mostly from oceanographic surveys, but also included squids caught by commercial fisheries, and a few specimens from museum collections. Squid response to abiotic variables, morphological... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Competition; Morphology; Myopsida; Population biology; Reproduction. |
| Ano: 2018 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1984-46702018000100337 |
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| Andrade,Carlos Mauricio Soares de; Garcia,Rasmo; Valentim,Judson Ferreira; Pereira,Odilon Gomes. |
| This study was carried out from October 2002 to December 2003 to evaluate the dynamics of sward condition and botanical composition of a mixed massaigrass (Panicum maximum x P. infestum, cv. Massai) and forage peanut (Arachis pintoi Ac 01) pasture, intermittently stocked at three daily herbage allowance levels (9.0, 14.5 and 18.4% live weight). Sward condition was characterized in each grazing cycle in terms of the pre and post-grazing sward height, forage mass and percentage of bare ground. Botanical composition (grass, legume and weeds) was evaluated before each grazing period. Sward height and forage mass increased linearly with increasing herbage allowance (HA) levels, and higher values were observed during the rainy season. Percentage of bare ground... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Arachis pintoi; Competition; Legume; Panicum maximum; Persistence; Western Amazon. |
| Ano: 2006 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-35982006000200002 |
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| GORDON,CALEB E.. |
| This paper is a critical literature review on the topic of the coexistence of similar species within ecological communities. A conceptual framework is provided for dividing coexistence studies and concepts into three distinct time scales. The first six sections deal primarily with ecological-scale, or mesoscale coexistence, defined as coexistence in the classic sense of the competitive exclusion principle and Lotka-Volterra models, wherein interacting populations have had enough time to reach equilibrium. The first four sections briefly review resource partitioning studies and competitive coexistence models, and discuss the relative contributions of, and interaction between empirical and theoretical approaches to the problem of ecological-scale... |
| Tipo: Journal article |
Palavras-chave: Coexistence; Competition; Community structure; Resource partitioning; Niche. |
| Ano: 2000 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2000000100016 |
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| Costa,Jaílson Penha; Mesquita,Mário Luiz Ribeiro. |
| ABSTRACT Knowledge of weed floristic composition and phytosociology are key factors for improving weed management in pastures. Information on weed species that occur in pastures in Northeast Brazil, particularly in Maranhão State is very limited. It is, therefore, important, to search for information to help farmers to control weeds in livestock farming. This paper describes the weed flora diversity and community structure parameters, including density, frequency, abundance and importance value for each weed species found in five pastures of same age and management in Maranhão State, Northeast Brazil. The weed survey was carried out using a wooden frame (80 cm x 30 cm) placed randomly on the soil surface 30 times in each pasture (n = 150). Weeds were... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Eragrostis ciliaris; Competition; Biological invasion; Allelopathy; Cyperus rotundus. |
| Ano: 2016 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1806-66902016000200414 |
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| Pezzopane,José Ricardo Macedo; Bernardi,Alberto Carlos de Campos; Azenha,Mariana Vieira; Oliveira,Patricia Perondi Anchão; Bosi,Cristiam; Pedroso,André de Faria; Esteves,Sérgio Novita. |
| ABSTRACT This study aimed to evaluate the production characteristics of pastures in integrated livestock production systems. For that, an experiment was carried out in São Carlos, SP, Brazil, from 2013 to 2015. Forage development, production and nutritive value were evaluated in five beef cattle production systems: extensive continuous stocking (Urochloa decumbens) = EXT; intensive = INT; crop-livestock = iCL; livestock-forest = iLF and crop-livestock-forest = iCLF. Rotational stocking pastures in INT, iCL, iLF and iCLF systems were established with Urochloa brizantha cv. BRS Piatã. In iCL and iCLF, pastures were renovated by resowing the grass simultaneously with corn. In iLF and iCLF, eucalyptus (Eucalyptus urograndis clone GG100) was planted in Apr 2011... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Urochloa brizantha; Eucalyptus urograndis; Solar radiation; Competition; Sustainability. |
| Ano: 2020 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162020000200402 |
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| Dias,Guilherme Faus da Silva; Alves,Pedro Luís da Costa Aguiar; Dias,Tomás Carneiro de Souza. |
| Brachiaria decumbens is becoming one the most common weeds growing in young coffee orchards because, besides its fast growth and difficulty of control, new coffee orchards are usually established in pasture areas. In order to verify the effect of B. decumbens plant density on the early growth of coffee (Coffea arabica L. cv. Catuaí Amarelo), a competition experiment was conducted under semi-controlled humidity conditions. Soil collected in a Typic Haplustox was placed in 70 L asbestos cement boxes and one coffee seedling was planted in each box. The B. decumbens seedlings were transplanted to the boxes at the 2-4 leaf stage. Treatments consisted of 0, 4, 8, 12, 16, 20, 24, 36, 48, and 60 weeds m-2. The experimental period started 120 days after... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Weed; Coffee; Competition; Growth suppression. |
| Ano: 2004 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162004000600003 |
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| Moreira,Cindy Silva; Alleoni,Luís Reynaldo Ferracciú. |
| The adsorption of heavy metals in soils affects their behavior in the environment and their bioavailability to plants. The knowledge of the adsorption mechanisms in competitive systems allows a more realistic evaluation of the metals' behavior in the soil than the single metal adsorption. The objectives of this study were (i) to evaluate Cd, Cu, Ni, and Zn adsorption in 14 surface samples (0-0.2 m) of representative soils of the Brazilian humid-tropical region, in competitive and non-competitive systems, and (ii) to establish metal affinity sequences for each soil, based in the maximum adsorption capacity (MAC) estimated by the Langmuir model. The Rhodic Eutrudox, the Kandiudalf Eutrudox, the Arenic Hapludalf, the Arenic Hapludult and the Typic Argiudoll... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Heavy metals; Competition; Tropical soil. |
| Ano: 2010 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162010000300008 |
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| Rocha,Carlos Frederico Duarte da; Duarte,Marcelo. |
| The use of nectar and pollen of a bromeliad by two heliconiine butterflies, Heliconius ethilla narcaea Godart, 1819 and H. sara apseudes (Hübner, [1813]) (Lepidoptera, Nymphalidae, Heliconiinae), is herein reported. Observations were made during a pollination study of Aechmea gracilis Lindman (Bromeliaceae, Bromelioidea) in a second-growth forest of the village Vila Dois Rios, Ilha Grande, Rio de Janeiro State, southeastern Brazil. Field observations showed that H. ethilla can be more aggressive than H. sara in exploiting A. gracilis floral resources. Temporal differences in the use of these resources were also observed: H. sara remained comparatively less time on flowers than H. ethilla. |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Lepidoptera; Heliconius; Pollination; Aechmea gracilis; Competition; Home range. |
| Ano: 2001 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0101-81752001000500027 |
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| FERREIRA,Débora Najara de SOUZA; CAMARGO,José Luís Campana; FERRAZ,Isolde Dorothea Kossmann. |
| ABSTRACT Polyembryony is the differentiation and development of multiple embryos in a single seed. This characteristic can provide advantages, as more than one embryo is produced with the same amount of resources, and the probability of establishment of at least one seedling increases. However, sibling seedlings may also increase competition, affecting development and survival. In the present study, the possible advantages and disadvantages of polyembryony were analyzed in the initial establishment of seedlings of Carapa surinamensis (Meliaceae), a tree species that produces monoembryonic or polyembryonic seeds. In this regard, the development of single seedlings was compared with a pair of seedlings emerging from polyembryonic seeds. We compared the... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Polyembryony; Andiroba; Crabwood; Seedling production; Competition. |
| Ano: 2019 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0044-59672019000200097 |
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| CESA-LUNA,Catherine; BAEZ,Antonino; QUINTERO-HERNÁNDEZ,Verónica; CRUZ-ENRÍQUEZ,Joel DE LA; CASTAÑEDA-ANTONIO,Ma Dolores; MUÑOZ-ROJAS,Jesús. |
| ABSTRACT Bacteria produce antimicrobial compounds to compete for nutrients and space in a particular habitat. Antagonistic interactions can be evaluated by several methodologies including the double-layer agar and simultaneous inhibition assays. Among the well-known inhibitory substances produced by bacteria are the broad-spectrum antibiotics, organic acids, siderophores, antifungal, and bacteriocins. The most studied bacterial genera able to produce these inhibitory substances are Enterococcus, Lactococcus, Streptomyces, Bacillus, Pseudomonas, Klebsiella, Escherichia, and Burkholderia. Some beneficial bacteria can promote plant growth and degrade toxic compounds in the environment representing an attractive solution to diverse issues in agriculture and... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Antagonism; Antibiotic; Competition; Inhibition; PGPR. |
| Ano: 2020 |
URL: http://www.scielo.org.co/scielo.php?script=sci_arttext&pid=S0120-548X2020000100140 |
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| Mesquita,Mário Luiz Ribeiro; Andrade,Leonaldo Alves de; Pereira,Walter Esfrain. |
| The objective of this study was to compare the ex situ and in situ floristic diversity of the soil weed seed bank of a rice field in northeastern Brazil. In a rice field in the county of Bacabal, located in the state of Maranhão, thirty 25-m² plots were laid out. From 15 plots, soil samples (6/plot; n = 90) were taken with a soil probe (25 × 16 × 3 cm) and placed in aluminum trays in the greenhouse. From the remaining 15 plots, weed samples (6/plot; n = 90) were taken with the same soil probe. The number of seeds was estimated by germination. We evaluated the numbers of species and individuals, as well as the density, frequency, abundance and importance value (IV) for each species. Diversity was computed by the Shannon index (H'). We recorded 13,892... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Cyperaceae; Competition; Biological invasion; Phytosociology; Smallholder farmers. |
| Ano: 2013 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-33062013000300001 |
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| Gastauer,Markus; Saporetti-Junior,Amílcar W.; Valladares,Fernando; Meira-Neto,João A. A.. |
| ABSTRACT Mussununga, an oligotrophic sandy savanna ecosystem, comprises distinct physiognomies along fire, water and nutrient availability gradients. Grasslands and woodlands are constrained at the opposite poles of these gradients, with grasslands occurring in areas with poorer soils and higher levels of both water-stress and fire intensity. According to the stress-dominance hypothesis, one might expect the importance of competition for community assembly to increase from grasslands to woodlands. Assuming conservation of ecological niches within evolutionary lineages, this should increase phylogenetic overdispersion from grasslands towards woodlands. To test this, we calculated phylogenetic diversity and community structure using different null models as... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Competition; Environmental filters; Mussunungas; Savanna woodlands; Stress-dominance hypothesis. |
| Ano: 2017 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-33062017000400531 |
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| Reigosa,Manuel; Gomes,Anabele Stefânia; Ferreira,Alfredo Gui; Borghetti,Fabian. |
| In this article, we review allelopathy studies conducted in Brazil or involving plant species that occur in the country. Conceptions and misconceptions associated with allelopathy, as well as some international criteria to be applied in allelopathic research, are presented and discussed. We observed a sharp increase in the number of papers on this subject conducted in Brazil between 1991 and 2010. However, most studies are conducted under laboratory conditions, lack a clear hypothesis or a solid justification, and typically make use of target species that do not co-exist with the donor species under natural conditions. We also found that most studies do not take the additional steps in order to purify and identify the bioactive molecules. We recommend that... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Allelopathy; Allelochemicals; Competition; Interference; Phytotoxicity; Weed control. |
| Ano: 2013 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-33062013000400001 |
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| Souza,Sthefanie do Nascimento Gomes de; Piedade,Maria Teresa Fernandez; Demarchi,Layon Oreste; Lopes,Aline. |
| ABSTRACT Amazon wetlands are among the most vulnerable ecosystem to be impacted by climate change, which may increase the frequency of extreme droughts and floods. We used Eichhornia crassipes and Pistia stratiotes, two abundant aquatic plants in the Amazon floodplains, to evaluate the effects of combined temperature and [CO2] increase on growth, physiology and ecological interactions. Individual and paired plants were deposited for three weeks in a microcosm under four IPCC scenarios: control (current temperature/CO2), mild (control + 1.5 ºC, 200 ppm CO2), intermediate (control + 2.5 ºC, 450 ppm CO2) and extreme (control + 3.5 ºC, 850 ppm CO2). P. stratiotes died after three weeks in the intermediate and extreme treatments; E. crassipes experienced no... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Biomass; Competition; Eichhornia crassipes; Pistia stratiotes; Wetlands. |
| Ano: 2021 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-33062021005002204 |
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| Mesquita, Mário Luiz Ribeiro; Andrade, Leonaldo Alves; Pereira, Walter Esfrain. |
| The objective of this research was to assess the density, floristic composition, phytosociology and diversity of a soil weed seed bank ex situ by germination in a greenhouse and in situ by weed sampling on a smallholder corn field located in Lago Verde County, Maranhão State. Fifteen pairs of 25 m2 plots were designated. In half of these plots, 90 soil samples were collected with an open metal template measuring 25 x 16 x 3 cm and placed in a greenhouse to germinate. In the other half, 90 weed samples were collected using the same metal template. We recorded a total of 1,998 individuals from 40 species, 31 genera and 16 families, from which 659 individuals germinated in situ and 1,339 exsitu. Density was higher ex situ, with 372 plants m-2. The Cyperaceae... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Ciências Agrárias Fitotecnia cyperaceae; Competition; Biological invasion; Phytosociology; Smallholder farmers Botânica Sistemática Plantas Invasoras. |
| Ano: 2014 |
URL: http://periodicos.uem.br/ojs/index.php/ActaSciAgron/article/view/19360 |
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| Scholten, Roger; Unesp-Jaboticabal; Parreira, Mariana Casari; Unesp-Jaboticabal; Alves, Pedro Luis da Costa Aguiar; Unesp-Jaboticabal. |
| Os feijões estão entre os alimentos mais antigos, fazendo parte da alimentação diária da população brasileira. Objetivou-se com este trabalho determinar o período de convivência anterior à interferência das plantas daninhas (PAI) na cultura do feijoeiro em diferentes espaçamentos e densidades de plantas. Os tratamentos foram constituídos de períodos de convivência entre a cultura e as plantas daninhas, sendo zero a dez, zero a 20, zero a 30, zero a 40, zero a 50, zero a 60, zero a 70 e zero a 80 dias e mais uma testemunha sem convívio com as plantas daninhas. Além dos períodos de convivência, realizaram-se ainda estudos com espaçamentos entre linhas de 0,45 e 0,60 m e mais duas densidades de semeadura: dez e 15 plantas m-1. Adotou-se delineamento... |
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Palavras-chave: Phaseolus vulgaris; Competição; Períodos de controle Phaseolus vulgari; Competition; Control periods. |
| Ano: 2011 |
URL: http://periodicos.uem.br/ojs/index.php/ActaSciAgron/article/view/5646 |
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| Registros recuperados: 214 | |
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