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Since consumers reflect the isotopic composition of an assimilated diet, stable isotopes can be a useful tool to address the feeding ecology of tropical snakes. This is the first study reporting carbon and nitrogen stable isotopic composition of Bothrops atrox (Linnaeus, 1758) living in different landscapes located in the lower Amazon river, encompassing four main natural landscapes of the Amazon: old-growth forests, várzeas (flooded forests), savannas, and pastures. Our null hypothesis is that the δ13C of forest specimens of B.atrox is more negative because forests are dominated by C3 plants, while C4 plants are common in the other landscapes. On the other hand, δ15N of forest specimens should be more positive, since the δ15N of old-growth forests are higher than plants of savanna, várzea, and pastures. Confirming our hypothesis, the δ13C of B. atrox scales of the Tapajós National Forest was approximate −25‰ to −24‰, increased to approximately −23.5‰ to −23.0‰ in the savanna and pasture, and to −21‰ in the várzea, showing an increased contribution of C4-derived carbon. Some specimens of B. atrox had δ15N as high as 18‰, which is much higher than the average δ15N of the snake's prey (7‰), confirming the apex position of B. atrox in the Amazon region. The δ15N values of the forest specimens were 5‰ higher than the savanna specimens, and this difference decreased to 3‰ between the forest and the pasture, and the várzea specimens. Finally, there were not large differences between δ15N values of livers and scales in any of the landscapes, suggesting a constant diet through time, and reinforcing the possibility of the use of snake's scale as a less invasive and non-lethal tissue to analyze.

RESUMO

The riverine population of the Amazon Basin are among the largest consumers of fish in the world, but the consumption patterns could be regionally distinct. Moreover, their total fish catches are not fully known. The objective of this work was to estimate the per capita fish consumption of the riverine people that inhabit the Paciência Island (Iranduba, Amazonas), where there is a fishing agreement in force. A total of 273 questionnaires were applied during the first two weeks of each month between April 2021 and March 2022. The sample unit was the residences. The questionnaire contained questions about the species captured and their quantities. Consumption was calculated by dividing the average monthly capture with the average number of residents per household interviewed, which was multiplied by the number of questionnaires applied. Thirty groups of consumed fish species belonging to 17 families and 5 orders were recorded. The total catch was 3,388.35 kg and the highest monthly catch was 602.60 kg during the falling-water season in October. Daily per capita fish consumption averaged 66.13 ± 29.21 g/day, with a peak of 116.45 g/day during the falling-water season in August. The high fish consumption rate highlighted the importance of fisheries management to food security and the maintenance of the community's lifestyle.

As populações amazônicas são uma das maiores consumidoras de pescado do mundo, contudo os padrões de consumo podem ser regionalmente distintos. Além disso, as capturas totais não são totalmente conhecidas. O objetivo do trabalho foi estimar o consumo per capita e as capturas de pescado por ribeirinhos residentes na Ilha da Paciência (Iranduba, Amazonas), onde há um acordo de pesca vigente. Foram aplicados no total 273 questionários durante as duas primeiras semanas de cada mês entre abril de 2021 e março de 2022. A unidade amostral foram as residências. O questionário continha perguntas sobre as espécies capturadas e respectivas quantidades. O consumo foi calculado pela divisão entre a média de captura mensal com a média de moradores por residência entrevistada que foi multiplicada pelo número de questionários aplicados. Foram registrados 30 grupos de espécies de peixes consumidos pertencentes a 17 famílias e 5 ordens. A captura total foi de 3.388,35 kg e a maior captura mensal foi de 602,60 kg durante a vazante no mês de outubro. O consumo de pescado per capita diário foi em média 66,13 ± 29,21 g/dia, com pico de 116,45 g/dia durante a vazante no mês de agosto. A alta taxa de consumo de pescado mostra a importância do manejo pesqueiro para a segurança alimentar e a manutenção do estilo de vida da comunidade.

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The objective of this study was to characterize the milk production in the central Amazonian region of the state of Amazonas. A questionnaire, consisting of objective questions, was applied to a sample of 50 properties located in the municipalities of Careiro da Várzea and Itacoatiara. The studied mesoregion develops an extensive dairy cattle breeding, where most of the producers have low schooling (60%), did not receive financing or financial incentive (70%) for the development of the dairy activity, nor are they engaged in associations or cooperatives (96%). Manual milking occurs in 100% of the analyzed properties, only once a day, with only 10% performing hygiene procedures in milking. The average production identified in the region was 3. 5L/cow/day. The uncontrolled natural mount is the only way used in the reproductive management of the properties. The current production is diversified in cattle and bubaline mixed-race (90%). In this region all the owners make use of native pastures. This region develops an extensive dairy cattle ranching, and the efficiency of the production system is limited due to inadequate sanitary, reproductive and food management, which favors low animal productivity.(AU)

O objetivo deste estudo foi caracterizar a produção leiteira na mesorregião centro amazonense do estado do Amazonas. Foi aplicado um questionário, constituído de questões objetivas, a uma amostra de 50 propriedades localizadas nos municípios de Careiro da Várzea e Itacoatiara. A mesorregião estudada desenvolve uma pecuária leiteira extensiva, onde a maioria dos produtores possui baixa escolaridade (60%), não receberam financiamento ou incentivo financeiro (70%) para o desenvolvimento da atividade leiteira e nem estão engajados em associações ou cooperativas (96%). A ordenha manual do leite ocorre em 100% das propriedades analisadas, uma única vez por dia, sendo que apenas (10%) realiza procedimento de higiene na ordenha. A produção média identificada na região foi de 3,5L/vaca/dia. A monta natural não controlada é a única forma utilizada no manejo reprodutivo das propriedades. A produção atual é diversificada em pecuária de animais bovinos e bubalinos mestiços (90%), nessa mesorregião todos os proprietários fazem uso de pastagens nativas. Essa mesorregião desenvolve uma pecuária leiteira extensiva, sendo a eficiência do sistema de produção limitado em decorrência do inadequado manejo sanitário, reprodutivo e alimentar, o que favorece a baixa produtividade animal.(AU)

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Events of catastrophic fish mortality in the lakes of the Amazonian floodplains are not uncommon. They are generally associated with thermal inversion of the water column, which is provoked by cold air masses that originate from the south of the continent. These events occur in the period of high water when the lakes are stratified. This paper reports an event of fish mortality that occurred during the low water season in a large floodplain system on the right-hand margin of the Amazon River. Information from seasoned fishers, who live in the same area where the event happened, and hydrological and satellite image analysis was used to identify the potential cause of fish mortality events. The amplitude of the flood pulse and the duration of extreme ebb showed to be the key factors responsible for the occurrence of events of fish mortality. These factors determine connectivity patterns between the floodplain lakes and the river channel, which are essential for maintaining water quality and the biota in the systems.

Eventos catastróficos de mortalidade de peixes em lagos de várzea da Amazônia não são incomuns, sendo, em geral, associados com a inversão térmica da coluna d'água, que é provocada por massas de ar frio que se originam no sul do continente. Esses eventos ocorrem no período de águas altas quando os lagos estão estratificados. Nesse artigo, relata-se um evento de mortalidade de peixes que ocorreu durante a estação de águas baixas em um grande sistema de várzea situado na margem direita do rio Amazonas. Usou-se o relato de pescadores residentes na área onde ocorreu o evento e com experiência na pesca, em conjunto com dados hidrológicos e imagens de satélite, para identificar potenciais causas do evento de mortalidade de peixes e propõe-se que a amplitude do pulso de inundação e a duração de secas extremas são os fatores chaves para a ocorrência dos eventos de mortalidade de peixes. Esses fatores determinam padrões de conectividade entre os lagos de várzea e o canal do rio, os quais são essenciais para a manutenção da qualidade da água e da biota nesses sistemas.

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Abstract The process of exotic species introduction is recognized as one of the greatest threats to the ecology and economy of the planet, due to changes in interactions in native biological communities. In this sense, reporting bioinvasions is the first step to understanding its introduction process and creating strategies to mitigate possible socio-environmental damages. Here we report the first records of Podocnemis unifilis introduced in the Northern Pantanal, Mato Grosso, Brazil. We obtained the species' first records occasionally during 2014 and 2015. In the following years from 2016 to 2019, we carried out systematic observations through nautical incursions on the Paraguay River, between the Sepotuba River mouth and the Taiamã Ecological Station (TES). We also included third part records, when it was possible to prove the species identification and registration sites. Podocnemis unifilis adults, hatchling and nests were recorded at different points along the Paraguay River. Our results indicate that P. unifilis was introduced close to the urban nucleus of Cáceres about 30 years ago. Currently, it has an established population, recording nests and hatchling for years in a row. A particular one is its occurrence at the TES, an important natural fish nursery and refuge for the wetland fauna. Thus, continuous monitoring is suggested from P.unifilis, since the Pantanal's environment with several different aquatic environments, offers favorable conditions for the species population increase in the Northern Pantanal.

Resumo O processo de introdução de espécies exóticas é reconhecido como uma das maiores ameaças à ecologia e economia do planeta, devido às mudanças nas interações em comunidades biológicas nativas. Nesse sentido, relatar as bioinvasões é o primeiro passo para entender seu processo de implantação e criar estratégias para mitigar possíveis danos socioambientais. Aqui relatamos os primeiros registros de P. unifilis introduzidos no Pantanal Norte, Mato Grosso, Brasil. Obtivemos os primeiros registros das espécies ocasionalmente durante 2014 e 2015. Nos anos seguintes, de 2016 a 2019, realizamos observações sistemáticas por meio de incursões náuticas no rio Paraguai, entre a foz do rio Sepotuba e a Estação Ecológica Taiamã (TES). Incluímos também registros de terceiros, quando foi possível comprovar os locais de identificação e registro das espécies. Adultos de Podcnemis unifilis, filhotes e ninhos foram registrados em diferentes pontos ao longo do rio Paraguai. Nossos resultados indicam que P. unifilis foi introduzido próximo ao núcleo urbano de Cáceres há cerca de 30 anos. Atualmente, ela tem uma população estabelecida, registrando ninhos e filhotes por anos consecutivos. Uma em particular é a sua ocorrência no TES, importante viveiro natural de peixes e refúgio da fauna pantaneira. Assim, sugere-se o monitoramento contínuo de P.unifilis, uma vez que o ambiente do Pantanal com diversos ambientes aquáticos distintos, oferece condições favoráveis para o aumento da população da espécie no Pantanal Norte.

RESUMO

This study aimed to determine the efficiency of estradiol cypionate (EC) as an ovulation inducer in a Timed Artificial Insemination protocol. 69 buffalo cows received an intravaginal progesterone device and 2mg of estradiol benzoate (EB) at D0. On D9, the intravaginal device was removed and 0.53mg of prostaglandin (PGF2α) and 400UI of equine chorionic gonadotrophin (eCG) were applied. The cows were distributed into two groups: the first group received 1mg of EC (ECG) in D9, and the second group received 1mg of EB (EBG) in D10. Inseminations occurred on D11. Ovarian activity and pregnancy diagnosis were analyzed by ultrasonography. There was no difference (P>0.05) in follicular diameter (9.6 ± 0.89mm vs. 10.7 ± 1.12mm; P=0.06), in ovulation rate (90.9% vs. 90.9%; P=1) and pregnancy rate (58.8% vs. 62.9%; P=0.79), however, buffalo cows from the ECG treatment have less time between P4 removal and ovulation when compared to EBG buffalos (37.4h vs. 52.8h; P=0.001), respectively. Thus, it was concluded that the implantation of TAI in the floodplain of Amazonas is feasible and the use of EC results in successful rates, similar to EB.(AU)

O objetivo deste trabalho foi determinar a eficiência do cipionato de estradiol (CE) como indutor de ovulação em um protocolo de inseminação artificial de tempo fixo. Para isso, 69 búfalas receberam no D0 um dispositivo intravaginal de progesterona e 2mg de benzoato de estradiol (BE). No D9, o dispositivo intravaginal foi removido e foram aplicados 0,53mg de prostaglandina (PGF2α) e 400UI de gonadotrofina coriônica equina (eCG), para, então, os animais serem divididos em dois grupos: um deles (GCE) recebeu 1mg de CE no D9, e o outro (GBE) recebeu 1mg de BE 24h após. As inseminações ocorreram no D11. A atividade ovariana e o diagnóstico de prenhez foram avaliados por ultrassonografia. Não houve diferença (P>0,05) no diâmetro folicular (9,6 ± 0,89mm vs. 10,7 ± 1,12mm; P=0,06), na taxa de ovulação (90,9% vs. 90,9%; P=1) e na taxa de prenhez (58,8% vs. 62,9%; P=0,79), no entanto búfalas do tratamento GCE apresentaram menor tempo entre a remoção da P4 e a ovulação, quando comparadas com as búfalas do GBE (37,4h vs. 52,8h; P=0,001), respectivamente. A implantação da IATF nas várzeas do Amazonas é viável e a utilização do CE resulta em taxas de sucesso similares ao BE.(AU)

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Few studies in the Amazon region have evaluated anuran diversity in urban forest fragments or in areas with differing degrees of anthropogenic impact. We determined the composition and abundance of the anurofauna in urban and rural sites within the municipality of Itacoatiara in central Amazonia, Brazil. Specimens were sampled from January 2012 to May 2013 in 10 urban sites and five rural sites. A total of 1,538 anurans (930 in rural sites and 608 in urban sites) were recorded, belonging to 29 species in five families. Species richness was higher in rural sites, with 10 exclusive species. All species found in urban sites were also found in rural sites, however, species abundance varied considerably between the habitats. Sampling- and individual-based rarefaction curves showed a tendency toward stabilization of species richness only in the urban sites. We concluded that the anuran assemblages in the urban sites are depauperate due to the absence of many species associated to pristine terra firme or várzea and igapó forests. Habitat loss and quality degradation in urban landscapes are the main factors threatening amphibian diversity. The anuran assemblages in our study areas were similar to those recorded in other Amazonian habitats. Conservation measures involving anurans in this region should consider the preservation of habitat mosaics, including both pristine terra firme, várzea and igapó forests. (AU)

Poucos estudos avaliaram a diversidade de anuros em fragmentos florestais urbanos ou em áreas com diferentes graus de impacto antrópico na Amazônia. Neste estudo foi determinada a composição e abundância de anuros em áreas urbanas e rurais no município de Itacoatiara, na Amazônia central, Brasil. Anuros foram amostrados entre janeiro de 2012 e maio de 2013 em 10 locais na área urbana e cinco na área rural. Um total de 1.538 indivíduos (930 na área rural e 608 na área urbana) foram registrados, compreendendo 29 espécies e cinco famílias. A área rural apresentou maior riqueza de espécies, com 10 espécies exclusivas. Todas as espécies identificadas na área urbana também foram encontradas na área rural, mas a abundância das espécies entre ambas áreas variou consideravelmente. Curvas de rarefação por amostragem e por número de indivíduos tenderam à estabilização na riqueza de espécies somente na área urbana. Concluímos que a comunidade de anuros na área urbana está empobrecida devido à ausência de muitas espécies associadas à ambientes inalterados de florestas de terra firme, várzea e igapó. A degradação da qualidade e a perda de habitat nas paisagens urbanas são os principais fatores que ameaçam a diversidade de anfíbios. A comunidade de anuros registrada neste estudo foi similar às de outros habitats na Amazônia. Medidas de conservação envolvendo anuros nesta região devem considerar a preservação de um mosaico de habitats que inclua áreas naturais de floresta de terra firme, várzea e igapó.(AU)

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RESUMO

Few studies in the Amazon region have evaluated anuran diversity in urban forest fragments or in areas with differing degrees of anthropogenic impact. We determined the composition and abundance of the anurofauna in urban and rural sites within the municipality of Itacoatiara in central Amazonia, Brazil. Specimens were sampled from January 2012 to May 2013 in 10 urban sites and five rural sites. A total of 1,538 anurans (930 in rural sites and 608 in urban sites) were recorded, belonging to 29 species in five families. Species richness was higher in rural sites, with 10 exclusive species. All species found in urban sites were also found in rural sites, however, species abundance varied considerably between the habitats. Sampling- and individual-based rarefaction curves showed a tendency toward stabilization of species richness only in the urban sites. We concluded that the anuran assemblages in the urban sites are depauperate due to the absence of many species associated to pristine terra firme or várzea and igapó forests. Habitat loss and quality degradation in urban landscapes are the main factors threatening amphibian diversity. The anuran assemblages in our study areas were similar to those recorded in other Amazonian habitats. Conservation measures involving anurans in this region should consider the preservation of habitat mosaics, including both pristine terra firme, várzea and igapó forests.(AU)

Poucos estudos avaliaram a diversidade de anuros em fragmentos florestais urbanos ou em áreas com diferentes graus de impacto antrópico na Amazônia. Neste estudo foi determinada a composição e abundância de anuros em áreas urbanas e rurais no município de Itacoatiara, na Amazônia central, Brasil. Anuros foram amostrados entre janeiro de 2012 e maio de 2013 em 10 locais na área urbana e cinco na área rural. Um total de 1.538 indivíduos (930 na área rural e 608 na área urbana) foram registrados, compreendendo 29 espécies e cinco famílias. A área rural apresentou maior riqueza de espécies, com 10 espécies exclusivas. Todas as espécies identificadas na área urbana também foram encontradas na área rural, mas a abundância das espécies entre ambas áreas variou consideravelmente. Curvas de rarefação por amostragem e por número de indivíduos tenderam à estabilização na riqueza de espécies somente na área urbana. Concluímos que a comunidade de anuros na área urbana está empobrecida devido à ausência de muitas espécies associadas à ambientes inalterados de florestas de terra firme, várzea e igapó. A degradação da qualidade e a perda de habitat nas paisagens urbanas são os principais fatores que ameaçam a diversidade de anfíbios. A comunidade de anuros registrada neste estudo foi similar às de outros habitats na Amazônia. Medidas de conservação envolvendo anuros nesta região devem considerar a preservação de um mosaico de habitats que inclua áreas naturais de floresta de terra firme, várzea e igapó.(AU)

RESUMO

The state of Rio Grande do Sul has about 20% of the total area as lowland soils, suitable for flooded rice (Oryza sativa). In order to mitigate damage caused by rice monoculture, new crops such as sorghum (Sorghum bicolor) and soybean (Glycine max) have been cultivated in these areas. With different qualities of crop residues, it is expected a change in soil organic matter (SOM) dynamics and consequently, nitrogen (N) availability. The objective of this study was to evaluate the influence of rice, soybean and sorghum crop residues on the N present in physical fractions of SOM of two lowland soils, using labeled 15N technique, under incubation for 180 days in aerobic condition and more 180 days in anaerobic condition. At 30, 180 and 360 days of incubation the remaining N of the plant residues and N destination from the residues in both soils were quantified in the physical fractions of SOM >250 μm, 250-53 μm and <53 μm. The soil with higher amount of clay+silt received a larger quantity of 15N from residues, while flooding of the soil after 180 days caused a loss of N added to the soil by the soybean and sorghum residues. In general, larger amounts of 15N were reported in the fraction <53 μm, associated with clay minerals, throughout the incubation period. These N losses should be considered in N fertilization for the following crops in rotation with flooded rice.(AU)

O Rio Grande do Sul possui cerca de 20% da área total de solos de terras baixas, propícias para o cultivo do arroz (Oryza sativa) irrigado por inundação. Buscando mitigar danos ocasionados com o monocultivo de arroz, novas culturas, como o sorgo (Sorghum bicolor) e a soja (Glycine max), têm sido cultivadas nestas áreas. Com diferentes qualidades de resíduos culturais, espera-se uma alteração na dinâmica da matéria orgânica do solo (MOS) e, consequentemente, do nitrogênio (N). O objetivo deste estudo foi avaliar a influência de resíduos culturais de arroz, soja e sorgo na quantidade de N em frações físicas da MOS de dois solos de terras baixas, utilizando a técnica de marcação isotópica de 15N das culturas e uma incubação por um ciclo de 180 dias em condição aeróbica e mais 180 dias em condição anaeróbica. Aos 30, 180 e 360 dias de incubação foi quantificado o N remanescente dos resíduos vegetais e destino do N proveniente dos resíduos nos dois solos em frações físicas da MOS >250 μm, 250-53 μm e <53 μm. O solo com maior quantidade de argila+silte recebeu maior quantidade de 15N dos resíduos, enquanto que o alagamento do solo após 180 dias de incubação ocasionou uma perda do N adicionado ao solo pelos resíduos de soja e sorgo. De maneira geral, foram encontradas maiores quantidades de 15N na fração <53 μm, associado aos argilominerais. As perdas de N devem ser consideradas na adubação nitrogenada para as culturas sequentes nos sistemas de rotação de culturas com arroz irrigado.(AU)

RESUMO

BACKGROUND AND AIMS: Identifying the processes that generate and maintain biodiversity requires understanding of how evolutionary processes interact with abiotic conditions to structure communities. Edaphic gradients are strongly associated with floristic patterns but, compared with climatic gradients, have received relatively little attention. We asked (1) How does the phylogenetic composition of palm communities vary along edaphic gradients within major habitat types? and (2) To what extent are phylogenetic patterns determined by (a) habitat specialists, (b) small versus large palms, and (c) hyperdiverse genera? METHODS: We paired data on palm community composition from 501 transects of 0.25 ha located in two main habitat types (non-inundated uplands and seasonally inundated floodplains) in western Amazonian rain forests with information on soil chemistry, climate, phylogeny and metrics of plant size. We focused on exchangeable base concentration (cmol+ kg-1) as a metric of soil fertility and a floristic index of inundation intensity. We used a null model approach to quantify the standard effect size of mean phylogenetic distance for each transect (a metric of phylogenetic community composition) and related this value to edaphic variables using generalized linear mixed models, including a term for spatial autocorrelation. KEY RESULTS: Overall, we recorded 112 008 individuals belonging to 110 species. Palm communities in non-inundated upland transects (but not floodplain transects) were more phylogenetically clustered in areas of low soil fertility, measured as exchangeable base concentration. In contrast, floodplain transects with more severe flood regimes (as inferred from floristic structure) tended to be phylogenetically clustered. Nearly half of the species recorded (44 %) were upland specialists while 18 % were floodplain specialists. In both habitat types, phylogenetic clustering was largely due to the co-occurrence of small-sized habitat specialists belonging to two hyperdiverse genera (Bactris and Geonoma). CONCLUSIONS: Edaphic conditions are associated with the phylogenetic community structure of palms across western Amazonia, and different factors (specifically, soil fertility and inundation intensity) appear to underlie diversity patterns in non-inundated upland versus floodplain habitats. By linking edaphic gradients with palm community phylogenetic structure, our study reinforces the need to integrate edaphic conditions in eco-evolutionary studies in order to better understand the processes that generate and maintain tropical forest diversity. Our results suggest a role for edaphic niche conservatism in the evolution and distribution of Amazonian palms, a finding with potential relevance for other clades.

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Abstract: Amazonian floodplain lakes host a high diversity of predatory fish which coexist and exploit the high diversity of available prey. Morphology could be the characteristic most closely associated with their preferred feeding sources (prey). However, it is unclear whether this association is direct or indirect. If it is indirect, swimming performance or preferential position in the water column could be the most evident characteristic. To examine the degree to which fish morphology of predator fish species is correlated to their dietary inputs, we compared the existence of morphological and feeding dissimilarity among eight predator species with the association between predator morphologies and preferred prey. We collected, measured, and sampled the stomach contents of fish from two lowland floodplain lakes associated with the Solimões River, Brazil, in May, August, and November of 2014. Of 187 collected fish across eight species, five species showed fish to be the most important item in their diets and three preferentially ate shrimp. Principal components analyses of ecomorphological attributes divided the species according to their ability to find the prey, swimming performance of the predator, and prey size. While there was significant distinction between the varying morphologies of predators, we were unable to distinguish between the specific diet of these species and did not find a correlation between morphology and feeding. These results are likely due to the fact that there is great abundance and diversity of available prey in the Amazonian floodplain lakes, so opportunistic feeding may be the primary foraging strategy of predator fish species living in these environments.

Resumo: Os lagos da várzea amazônica abrigam uma elevada riqueza de peixes predadores, com características morfológicas distintas, possibilitando explorar com sucesso várias presas disponíveis. Estas características morfológicas podem ser a associação mais próxima com suas fontes de alimentação preferidas (presa). Todavia, esta associação pode ser de forma direta ou indireta. Neste último caso, o desempenho da natação ou a posição preferencial na coluna d'água pode ser uma característica mais evidente. Para examinar o grau com que a morfologia de peixes predadores está correlacionada com seus itens alimentares, foram comparadas a existência de dissimilaridade morfológica e de alimentação entre oito espécies predadoras e a associação entre suas morfologias e suas presas. Foram coletados, medidos e amostrados o conteúdo estomacal de peixes de dois lagos de várzea associados ao rio Solimões, nos meses de maio, agosto e novembro de 2014. Dos 187 peixes coletados, em oito espécies, cinco mostraram que peixe era o item mais importante em suas dietas e três apresentaram preferência por camarão. A análise dos componentes principais dos atributos ecomorfológicos dividiu as espécies de acordo com a capacidade de encontrar sua presa, o desempenho de natação do predador e o tamanho da presa. Embora apresentasse distinção significativa entre suas características morfológicas, não foi encontrado distinção entre a dieta dessas espécies e nem correlação entre morfologia e alimentação. Esses resultados provavelmente se devem ao fato de que há grande abundância e diversidade de presas disponíveis nos lagos da planície de inundação da Amazônia, de modo que a alimentação oportunista pode ser a principal estratégia de forrageamento das espécies de peixes predadores que vivem nesses ambientes.

RESUMO

ABSTRACT: The state of Rio Grande do Sul has about 20% of the total area as lowland soils, suitable for flooded rice (Oryza sativa). In order to mitigate damage caused by rice monoculture, new crops such as sorghum (Sorghum bicolor) and soybean (Glycine max) have been cultivated in these areas. With different qualities of crop residues, it is expected a change in soil organic matter (SOM) dynamics and consequently, nitrogen (N) availability. The objective of this study was to evaluate the influence of rice, soybean and sorghum crop residues on the N present in physical fractions of SOM of two lowland soils, using labeled 15N technique, under incubation for 180 days in aerobic condition and more 180 days in anaerobic condition. At 30, 180 and 360 days of incubation the remaining N of the plant residues and N destination from the residues in both soils were quantified in the physical fractions of SOM >250 μm, 250-53 μm and <53 μm. The soil with higher amount of clay+silt received a larger quantity of 15N from residues, while flooding of the soil after 180 days caused a loss of N added to the soil by the soybean and sorghum residues. In general, larger amounts of 15N were reported in the fraction <53 μm, associated with clay minerals, throughout the incubation period. These N losses should be considered in N fertilization for the following crops in rotation with flooded rice.

RESUMO: O Rio Grande do Sul possui cerca de 20% da área total de solos de terras baixas, propícias para o cultivo do arroz (Oryza sativa) irrigado por inundação. Buscando mitigar danos ocasionados com o monocultivo de arroz, novas culturas, como o sorgo (Sorghum bicolor) e a soja (Glycine max), têm sido cultivadas nestas áreas. Com diferentes qualidades de resíduos culturais, espera-se uma alteração na dinâmica da matéria orgânica do solo (MOS) e, consequentemente, do nitrogênio (N). O objetivo deste estudo foi avaliar a influência de resíduos culturais de arroz, soja e sorgo na quantidade de N em frações físicas da MOS de dois solos de terras baixas, utilizando a técnica de marcação isotópica de 15N das culturas e uma incubação por um ciclo de 180 dias em condição aeróbica e mais 180 dias em condição anaeróbica. Aos 30, 180 e 360 dias de incubação foi quantificado o N remanescente dos resíduos vegetais e destino do N proveniente dos resíduos nos dois solos em frações físicas da MOS >250 μm, 250-53 μm e <53 μm. O solo com maior quantidade de argila+silte recebeu maior quantidade de 15N dos resíduos, enquanto que o alagamento do solo após 180 dias de incubação ocasionou uma perda do N adicionado ao solo pelos resíduos de soja e sorgo. De maneira geral, foram encontradas maiores quantidades de 15N na fração <53 μm, associado aos argilominerais. As perdas de N devem ser consideradas na adubação nitrogenada para as culturas sequentes nos sistemas de rotação de culturas com arroz irrigado.

RESUMO

A irrigação por aspersão pode minimizar os efeitos negativos da deficiência hídrica e aumentar o rendimento e desempenho de sementes de soja no campo. Assim, o objetivo do trabalho foi avaliar o efeito da irrigação por aspersão no rendimento e potencial fisiológico das sementes de soja produzidas em solos de várzea. Os tratamentos foram constituídos por oito cultivares de soja e dois regimes hídricos: com e sem irrigação por aspersão. Foram utilizadas cultivares de soja BMX Força RR, BRS Tertúlia RR, CD 249 RR STS, BMX Potência RR, do grupo de maturação (GM) 6 e BRS 246 RR, BRS Charrua RR, BRS Taura RR, e CD 231 RR, do grupo de maturação (GM) 7. As variáveis analisadas foram o rendimento de sementes, germinação, primeira contagem da germinação, envelhecimento acelerado, condutividade elétrica, emergência em campo e peso de mil sementes. A irrigação por aspersão na cultura da soja em solo de várzea proporciona acréscimos no rendimento de todas as cultivares em estudo, variando os acréscimos entre 32% a 139% e proporciona acréscimo no potencial fisiológico de sementes das cultivares BMX Força RR, BRS Tertúlia RR, CD 249 RR STS, BMX Potência RR, e BRS Taura RR.

The sprinkler irrigation reduces the negative effects of water deficit and increases the yield and performance of soybean seeds on field. Thus, the objective of work was to evaluate the effect of sprinkler irrigation on yield and physiological potential of soybean seeds produced in lowland soils. The treatments consisted of 8 soybean cultivars and two water regimes: with and without sprinkler irrigation. This work was developed using soybean seeds of the cultivars BMX Força RR, BRS Tertúlia RR, CD 249 RR STS, BMX Potência RR and BRS 246 RR, BRS Charrua RR, BRS Taura RR, and CD 231 RR. The variables analyzed were the seeds yield, germination, first count of germination, accelerated aging, electrical conductivity, field emergence, and seed weight. The sprinkler irrigation on soybean crop in lowland soil increase in seed yield of all cultivars studied, the increase varied from 32% to 139%. The sprinkler irrigation has improved seed performance of cultivars BMX Força RR, BRS Tertúlia RR, CD 249 RR STS, BMX Potência RR, and BRS Taura.

Assuntos

RESUMO

A irrigação por aspersão pode minimizar os efeitos negativos da deficiência hídrica e aumentar o rendimento e desempenho de sementes de soja no campo. Assim, o objetivo do trabalho foi avaliar o efeito da irrigação por aspersão no rendimento e potencial fisiológico das sementes de soja produzidas em solos de várzea. Os tratamentos foram constituídos por oito cultivares de soja e dois regimes hídricos: com e sem irrigação por aspersão. Foram utilizadas cultivares de soja BMX Força RR, BRS Tertúlia RR, CD 249 RR STS, BMX Potência RR, do grupo de maturação (GM) 6 e BRS 246 RR, BRS Charrua RR, BRS Taura RR, e CD 231 RR, do grupo de maturação (GM) 7. As variáveis analisadas foram o rendimento de sementes, germinação, primeira contagem da germinação, envelhecimento acelerado, condutividade elétrica, emergência em campo e peso de mil sementes. A irrigação por aspersão na cultura da soja em solo de várzea proporciona acréscimos no rendimento de todas as cultivares em estudo, variando os acréscimos entre 32% a 139% e proporciona acréscimo no potencial fisiológico de sementes das cultivares BMX Força RR, BRS Tertúlia RR, CD 249 RR STS, BMX Potência RR, e BRS Taura RR.(AU)

The sprinkler irrigation reduces the negative effects of water deficit and increases the yield and performance of soybean seeds on field. Thus, the objective of work was to evaluate the effect of sprinkler irrigation on yield and physiological potential of soybean seeds produced in lowland soils. The treatments consisted of 8 soybean cultivars and two water regimes: with and without sprinkler irrigation. This work was developed using soybean seeds of the cultivars BMX Força RR, BRS Tertúlia RR, CD 249 RR STS, BMX Potência RR and BRS 246 RR, BRS Charrua RR, BRS Taura RR, and CD 231 RR. The variables analyzed were the seeds yield, germination, first count of germination, accelerated aging, electrical conductivity, field emergence, and seed weight. The sprinkler irrigation on soybean crop in lowland soil increase in seed yield of all cultivars studied, the increase varied from 32% to 139%. The sprinkler irrigation has improved seed performance of cultivars BMX Força RR, BRS Tertúlia RR, CD 249 RR STS, BMX Potência RR, and BRS Taura.(AU)

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The flood pulse is the main factor structuring and differentiating the ecological communities of Amazonian unflooded (terra firme) and seasonally-flooded (várzea) forests as they require unique adaptations to survive the prolonged annual floods. Therefore, várzea and terra firme forests hammer out a spatio-temporal mosaic of resource availability, which may result in landscape scale seasonal movements of terrestrial vertebrates between adjacent forest types. Yet the lateral movements of terrestrial vertebrates between hydrologically distinct neighbouring forest types exhibiting staggered resource availability remains poorly understood, despite the important implications of this spatial dynamic for the ecology and conservation of forest wildlife. We examined the hypothesis of terrestrial fauna seasonal movements between two adjacent forest types at two contiguous sustainable-use forest reserves in Western Brazilian Amazonia. We used camera trapping data on the overall species richness, composition, and abundance of nine major vertebrate trophic guilds to infer on terrestrial vertebrate movements as a function of seasonal changes in floodplain water level. Species richness differed in neighboring terra firme forests between the high-and low-water phases of the flood pulse and terra firme forests were more species rich than várzea forests. There were clear differences in species composition between both forest types and seasons. Generalized Linear Models showed that water level was the main factor explaining aggregate abundance of all species and three trophic guilds. Our results indicate that the persistence of viable populations of large terrestrial vertebrates adjacent to major Amazonian rivers requires large, well-connected forest landscapes encompassing different forest types to ensure large-scale lateral movements by forest wildlife.

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Patterns of habitat selection are influenced by local productivity, resource availability, and predation risk. Species have taken millions of years to hone the macro- and micro-habitats they occupy, but these may now overlap with contemporary human threats within natural species ranges. Wattled Curassow (Crax globulosa), an endemic galliform species of the western Amazon, is threatened by both hunting and habitat loss, and is restricted to white-water floodplain forests of major Amazonian rivers. In this study conducted along the Juruá River, Amazonas, Brazil, we quantified the ranging ecology and fine-scale patterns of habitat selection of the species. We estimated the home range size of C. globulosa using conventional VHF telemetry. To estimate patterns of habitat selection, we used geo-locations of day ranges to examine the extent and intensity of use across the floodplain, which were then compared to a high-resolution flood map of the study area. We captured two females and one male, which we monitored for 13 months between September 2014 and September 2015. Average home range size was 283 ha, based on the 95% aLoCoH estimator. Wattled Curassows selected areas of prolonged flood pulses (six to eight months/year) and had a consistent tendency to be near open water, usually in close proximity to river banks and lakes, especially during the dry season. Amazonian floodplains are densely settled, and the small portions of floodplain habitat used by Wattled Curassows are both the most accessible to hunters and most vulnerable to deforestation. As a result, the geographic and ecological distribution of Wattled Curassows places them at much higher extinction risk at multiple spatial scales, highlighting the need to consider habitat preferences within their conservation strategy.

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Although nesting ecology is well studied in several crocodilian species, it is not known how nest attendance influences physiology and body condition of nesting females. In this study, we describe body condition and serum biochemical values of nesting female, non-nesting female and male spectacled caiman (Caiman crocodilus) and black caiman (Melanosuchus niger) in two areas of Central Amazonia. We also evaluated the effect of nest age and nest distance to water on body condition and blood parameters of nesting females. Body condition and plasmatic concentrations of glucose, triglycerides, lactate and uric acid of nesting females were significantly different from those of non-nesting females and males in C. crocodilus, but not in M. niger. Our study also demonstrated that nest age and distance to water had a negative effect on female body condition in C. crocodilus, but not in M. niger. Female C. crocodilus attending older nests or nests built further away from permanent water bodies tended to have lower body condition. Our results demonstrate that the nesting strategy of C. crocodilus has a metabolic cost associated with nest attendance for nesting females, which appear to depend on accumulated energetic reserves during nest attendance. In contrast, nest attendance had little effect on the physiology of female M. niger.

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Five new species of Monopelopia from Brazil are described and illustrated, four of which are based on all life stages and one on adult male and pupa. The immature stages of Monopelopia edentata sp. nov. were collected in bromeliad phytotelmata, while the other species were collected associated with aquatic vegetation. New records for M. boliekae Beck & Beck and M. caraguata Mendes, Marcondes & Pinho are provided, as well as updated identification keys for males and immatures of the Nearctic and Neotropical Monopelopia species.

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The phylogenetic community assembly approach has been used to elucidate the role of ecological and historical processes in shaping tropical tree communities. Recent studies have shown that stressful environments, such as seasonally dry, white-sand and flooded forests tend to be phylogenetically clustered, arguing for niche conservatism as the main driver for this pattern. Very few studies have attempted to identify the lineages that contribute to such assembly patterns. We aimed to improve our understanding of the assembly of flooded forest tree communities in Northern South America by asking the following questions: are seasonally flooded forests phylogenetically clustered? If so, which angiosperm lineages are over-represented in seasonally flooded forests? To assess our hypotheses, we investigated seasonally flooded and terra firme forests from the Magdalena, Orinoco and Amazon Basins, in Colombia. Our results show that, regardless of the river basin in which they are located, seasonally flooded forests of Northern South America tend to be phylogenetically clustered, which means that the more abundant taxa in these forests are more closely related to each other than expected by chance. Based on our alpha and beta phylodiversity analyses we interpret that eudicots are more likely to adapt to extreme environments such as seasonally flooded forests, which indicates the importance of environmental filtering in the assembly of the Neotropical flora.

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