RESUMO

The Western Antarctic Peninsula (WAP) experiences one of the highest rates of sea surface warming globally, leading to potential changes in biological communities. Long-term phytoplankton monitoring in Potter Cove (PC, King George Island, South Shetlands) from the 1990s to 2009 revealed consistently low biomass values, and sporadic blooms dominated by cold-water microplankton diatoms. However, a significant change occurred between 2010 and 2020, marked by a notable increase in intense phytoplankton blooms in the region. During this period, the presence of a nanoplankton diatom, Shionodiscus gaarderae, was documented for the first time. In some instances, this species even dominated the blooms. S. gaarderae is recognized for producing blooms in temperate waters in both hemispheres. However, its blooming in the northern Southern Ocean may suggest either a recent introduction or a range shift associated with rising temperatures in the WAP, a phenomenon previously observed in experimental studies. The presence of S. gaarderae could be viewed as a warning sign of significant changes already underway in the northern WAP plankton communities. This includes the potential replacement of microplankton diatoms by smaller nanoplankton species. This study, based on observations along the past decade, and compared to the previous 20 years, could have far-reaching implications for the structure of the Antarctic food web.

Assuntos

RESUMO

Historically, the neogregarine Apicystis bombi was isolated almost exclusively from bumble bees (Bombus spp.) where it disrupts adipose tissue, increasing hosts' mortality rates. Records in solitary bees are scarce worldwide. To check for its presence in carpenter bees (genus Xylocopa), campaigns were performed in Argentina capturing 154 individuals of five species (X. augusti, X. splendidula, X. atamisquensis, X. frontalis, X. nigrocincta). The presence of A. bombi was detected by molecular means in X. augusti, X. atamisquensis, and X. nigrocincta in four of the nine provinces screened. The pathogenesis and eventual impact that A. bombi may cause in individuals or populations of Xylocopa species remain unknown. The presence of A. bombi in northern Argentina would be contradictory to the hypothesis that its occurrence is the exclusive result of its introduction to South America through invasive, infected exotic bumble bees.

RESUMO

Projects on river basin integration are keen social-economical drivers in dry regions like the Brazilian semiarid, however, there are concerning ecological impacts implied in those projects. In a long-term analysis, ichthyofauna colonization and spread through the East Axis of the São Francisco River Integration Project (SFIP) was monitored to assess possible impacts on the receiving Paraíba River basin. The fish were collected semiannually (2012 to 2021) from 19 sites in the São Francisco (SF) and Paraíba (PB) basins. A total of 69 fish species were recorded, with distinct fish assemblages between SF (n = 50), PB (n = 35), and the SFIP artificial reservoirs (n = 25). The SFIP reservoirs were colonized by species from the donor basin (SF). In a pioneer finding, Anchoviella vaillanti was recorded for the first time in the receiving basin and it is in the process of establishment. The two SF species that reached PB through the SFIP canals (A. vaillanti and Moenkhausia costae) may be using their year-round reproduction and wide diet to successful spread and colonize the new environment. Since we detected species with potential to reach the receiving basin and became invasives, the implementation of barriers to contain their spread are recommended.(AU)

Projetos de integração de bacias hidrográficas são socialmente importantes em regiões como o semiárido brasileiro, porém há impactos ecológicos preocupantes implícitos nesses grandes projetos de infraestrutura. A colonização e dispersão da ictiofauna pelo Eixo Leste do Projeto de Integração do Rio São Francisco (PISF) foi monitorada para avaliar possíveis impactos na bacia receptora do rio Paraíba do Norte. Os peixes foram coletados semestralmente (2012 a 2021) em 19 locais das bacias do São Francisco (SF) e Paraíba (PB). Foram registradas 69 espécies de peixes, sendo 50 nos pontos do SF, 25 nos reservatórios artificiais ao longo do PISF e 35 nos pontos do PB. As assembleias de peixes das bacias do SF, PB e dos reservatórios do PISF foram significativamente distintas. Os reservatórios do PISF foram colonizados por espécies provenientes da bacia doadora (SF). Anchoviella vaillanti foi registrada pela primeira vez na bacia receptora do PB e está em processo de estabelecimento. As duas espécies do SF que chegaram ao PB pelos canais do PISF (A. vaillanti e Moenkhausia costae) apresentaram dieta e estratégias reprodutivas que permitem o sucesso na disseminação e colonização. Uma vez que foram detectadas espécies com potencial de atingir a bacia receptora, recomenda-se o monitoramento e manejo contínuos.(AU)

Assuntos

RESUMO

Abstract The Australian red-claw crayfish, Cherax quadricarinatus, has been introduced for aquaculture purposes worldwide and consequently colonized natural environments, where it might cause ecosystem services losses or adversely affect native species and the local environment. This species was first found in Pequenos Libombos Reservoir in Maputo Province, Southern Mozambique in the late 2009 and is linked to reduction in tilapia fisheries. This study, conducted in 2015 under controlled conditions, aimed to assess the interspecific relationships between the Mozambique tilapia (Oreochromis mossambicus) and the alien crayfish. For both species, no significant differences in growth and survival rates were found between animals reared in the presence versus the absence of heterospecifics, indicating no direct deleterious interspecific effects. Behavioural observations revealed that fish and crayfish competed for shelter and food. Both species reduced the foraging in the presence of heterospecifics during feeding period, in the daytime. Crayfish seemed to have an advantage in competition for shelter, suggesting that they may interfere with tilapia sheltering activity and make tilapia vulnerable to predators in natural habitats.

Resumo O lagostim australiano, Cherax quadricarinatus, tem sido introduzido para fins de aquicultura em todo o mundo e, consequentemente, colonizado ambientes naturais, onde pode coexistir com a biota local sem causar perdas nos serviços dos ecossistemas ou afetar negativamente as espécies nativas e o meio ambiente local. Esta espécie foi encontrada pela primeira vez na Albufeira dos Pequenos Libombos, na Província de Maputo, sul de Moçambique, no final de 2009 e foi relacionada à redução da pesca de tilápias registrada na mesma localidade. Este estudo, conduzido em 2015 sob condições controladas, teve como objetivo avaliar as relações interespecíficas entre a tilápia de Moçambique (Oreochromis mossambicus) e o lagostim invasor (C. quadricarinatus). Para ambas espécies, não foram encontradas diferenças significativas nas taxas de crescimento e sobrevivência entre animais criados na presença versus ausência de heteroespecíficos, indicando ausência de efeitos deletérios interespecíficos diretos. Observações comportamentais revelaram que peixes e lagostins competiam por abrigo e comida. Ambas espécies reduziram o forrageamento na presença de heteroespecíficos durante o período de alimentação, no período diurno. O lagostim parece ter uma vantagem na competição por abrigos, sugerindo que, em habitats naturais eles podem provocar o deslocamento de tilápias de seus abrigos, e deste modo tornar as tilápias vulneráveis aos predadores.

Assuntos

RESUMO

The Australian red-claw crayfish, Cherax quadricarinatus, has been introduced for aquaculture purposes worldwide and consequently colonized natural environments, where it might cause ecosystem services losses or adversely affect native species and the local environment. This species was first found in Pequenos Libombos Reservoir in Maputo Province, Southern Mozambique in the late 2009 and is linked to reduction in tilapia fisheries. This study, conducted in 2015 under controlled conditions, aimed to assess the interspecific relationships between the Mozambique tilapia (Oreochromis mossambicus) and the alien crayfish. For both species, no significant differences in growth and survival rates were found between animals reared in the presence versus the absence of heterospecifics, indicating no direct deleterious interspecific effects. Behavioural observations revealed that fish and crayfish competed for shelter and food. Both species reduced the foraging in the presence of heterospecifics during feeding period, in the daytime. Crayfish seemed to have an advantage in competition for shelter, suggesting that they may interfere with tilapia sheltering activity and make tilapia vulnerable to predators in natural habitats.(AU)

O lagostim australiano, Cherax quadricarinatus, tem sido introduzido para fins de aquicultura em todo o mundo e, consequentemente, colonizado ambientes naturais, onde pode coexistir com a biota local sem causar perdas nos serviços dos ecossistemas ou afetar negativamente as espécies nativas e o meio ambiente local. Esta espécie foi encontrada pela primeira vez na Albufeira dos Pequenos Libombos, na Província de Maputo, sul de Moçambique, no final de 2009 e foi relacionada à redução da pesca de tilápias registrada na mesma localidade. Este estudo, conduzido em 2015 sob condições controladas, teve como objetivo avaliar as relações interespecíficas entre a tilápia de Moçambique (Oreochromis mossambicus) e o lagostim invasor (C. quadricarinatus). Para ambas espécies, não foram encontradas diferenças significativas nas taxas de crescimento e sobrevivência entre animais criados na presença versus ausência de heteroespecíficos, indicando ausência de efeitos deletérios interespecíficos diretos. Observações comportamentais revelaram que peixes e lagostins competiam por abrigo e comida. Ambas espécies reduziram o forrageamento na presença de heteroespecíficos durante o período de alimentação, no período diurno. O lagostim parece ter uma vantagem na competição por abrigos, sugerindo que, em habitats naturais eles podem provocar o deslocamento de tilápias de seus abrigos, e deste modo tornar as tilápias vulneráveis aos predadores.(AU)

Assuntos

RESUMO

Abstract The Australian red-claw crayfish, Cherax quadricarinatus, has been introduced for aquaculture purposes worldwide and consequently colonized natural environments, where it might cause ecosystem services losses or adversely affect native species and the local environment. This species was first found in Pequenos Libombos Reservoir in Maputo Province, Southern Mozambique in the late 2009 and is linked to reduction in tilapia fisheries. This study, conducted in 2015 under controlled conditions, aimed to assess the interspecific relationships between the Mozambique tilapia (Oreochromis mossambicus) and the alien crayfish. For both species, no significant differences in growth and survival rates were found between animals reared in the presence versus the absence of heterospecifics, indicating no direct deleterious interspecific effects. Behavioural observations revealed that fish and crayfish competed for shelter and food. Both species reduced the foraging in the presence of heterospecifics during feeding period, in the daytime. Crayfish seemed to have an advantage in competition for shelter, suggesting that they may interfere with tilapia sheltering activity and make tilapia vulnerable to predators in natural habitats.

Resumo O lagostim australiano, Cherax quadricarinatus, tem sido introduzido para fins de aquicultura em todo o mundo e, consequentemente, colonizado ambientes naturais, onde pode coexistir com a biota local sem causar perdas nos serviços dos ecossistemas ou afetar negativamente as espécies nativas e o meio ambiente local. Esta espécie foi encontrada pela primeira vez na Albufeira dos Pequenos Libombos, na Província de Maputo, sul de Moçambique, no final de 2009 e foi relacionada à redução da pesca de tilápias registrada na mesma localidade. Este estudo, conduzido em 2015 sob condições controladas, teve como objetivo avaliar as relações interespecíficas entre a tilápia de Moçambique (Oreochromis mossambicus) e o lagostim invasor (C. quadricarinatus). Para ambas espécies, não foram encontradas diferenças significativas nas taxas de crescimento e sobrevivência entre animais criados na presença versus ausência de heteroespecíficos, indicando ausência de efeitos deletérios interespecíficos diretos. Observações comportamentais revelaram que peixes e lagostins competiam por abrigo e comida. Ambas espécies reduziram o forrageamento na presença de heteroespecíficos durante o período de alimentação, no período diurno. O lagostim parece ter uma vantagem na competição por abrigos, sugerindo que, em habitats naturais eles podem provocar o deslocamento de tilápias de seus abrigos, e deste modo tornar as tilápias vulneráveis aos predadores.

RESUMO

Abstract The Australian red-claw crayfish, Cherax quadricarinatus, has been introduced for aquaculture purposes worldwide and consequently colonized natural environments, where it might cause ecosystem services losses or adversely affect native species and the local environment. This species was first found in Pequenos Libombos Reservoir in Maputo Province, Southern Mozambique in the late 2009 and is linked to reduction in tilapia fisheries. This study, conducted in 2015 under controlled conditions, aimed to assess the interspecific relationships between the Mozambique tilapia (Oreochromis mossambicus) and the alien crayfish. For both species, no significant differences in growth and survival rates were found between animals reared in the presence versus the absence of heterospecifics, indicating no direct deleterious interspecific effects. Behavioural observations revealed that fish and crayfish competed for shelter and food. Both species reduced the foraging in the presence of heterospecifics during feeding period, in the daytime. Crayfish seemed to have an advantage in competition for shelter, suggesting that they may interfere with tilapia sheltering activity and make tilapia vulnerable to predators in natural habitats.

Resumo O lagostim australiano, Cherax quadricarinatus, tem sido introduzido para fins de aquicultura em todo o mundo e, consequentemente, colonizado ambientes naturais, onde pode coexistir com a biota local sem causar perdas nos serviços dos ecossistemas ou afetar negativamente as espécies nativas e o meio ambiente local. Esta espécie foi encontrada pela primeira vez na Albufeira dos Pequenos Libombos, na Província de Maputo, sul de Moçambique, no final de 2009 e foi relacionada à redução da pesca de tilápias registrada na mesma localidade. Este estudo, conduzido em 2015 sob condições controladas, teve como objetivo avaliar as relações interespecíficas entre a tilápia de Moçambique (Oreochromis mossambicus) e o lagostim invasor (C. quadricarinatus). Para ambas espécies, não foram encontradas diferenças significativas nas taxas de crescimento e sobrevivência entre animais criados na presença versus ausência de heteroespecíficos, indicando ausência de efeitos deletérios interespecíficos diretos. Observações comportamentais revelaram que peixes e lagostins competiam por abrigo e comida. Ambas espécies reduziram o forrageamento na presença de heteroespecíficos durante o período de alimentação, no período diurno. O lagostim parece ter uma vantagem na competição por abrigos, sugerindo que, em habitats naturais eles podem provocar o deslocamento de tilápias de seus abrigos, e deste modo tornar as tilápias vulneráveis aos predadores.

RESUMO

Introduction of fish species is a globally widespread practice that causes losses of native species and homogenization of diversity within and across continents. Diet assessments are important tools to depict the ecological function of species introduced into novel ecosystem and possible direct and indirect ecological effects. In this study, we compare the diet of Piaractus brachypomus, a mainly frugivorous Neotropical fish, introduced into the Sepik-Ramu River Basin (Papua New Guinea) nearly two decades ago, to that of similar size individuals from Neotropical populations in the Amazon and Orinoco River basins (South America). In contrast to native populations that feed mainly on terrestrial plants and invertebrates, the diet of introduced P. brachypomus is mainly composed of fish remains and aquatic plants, while terrestrial plants are frequently consumed but in relatively smaller amounts. These findings show that P. brachypomus has an inherently plastic diet that can be adjusted when displaced to a novel geographic area. While trophic plasticity increases the likelihood of a species to establish breeding populations after its introduction, it also reduces our ability to predict negative effects on native species.

La introducción de peces es una práctica que se extiende globalmente y que causa perdida de especies nativas y homogenización de la diversidad dentro y entre continentes. Los estudios de dieta son herramientas útiles para definir la función ecológica de una especie introducida en un ecosistema nuevo y los posibles efectos directos e indirectos. En este estudio describimos la dieta de Piaractus brachypomus, una especie de pez Neotropical principalmente frugívora, que fue introducida en el río Sepik (Papua Nueva Guinea) hace casi dos décadas; y la comparamos con aquella de individuos de tamaño corporal similar de poblaciones nativas en las cuencas de los ríos Amazonas y Orinoco (América del Sur). En contraste con las poblaciones nativas que se alimentan principalmente de frutas y semillas, plantas e invertebrados terrestres, la dieta de individuos de P. brachypomus introducidos se compone principalmente de restos de peces y plantas acuáticas, mientras que plantas terrestres son consumidas frecuentemente pero en pequeñas cantidades. Estos resultados indican que P. brachypomus tiene una dieta plástica que puede adaptarse cuando la especie se desplaza a un área geográfica nueva. A pesar de que la plasticidad trófica aumenta la probabilidad de que una especie establezca poblaciones reproductivas después de la introducción, también reduce nuestra habilidad de predecir los efectos negativos sobre especies nativas.

Assuntos

RESUMO

Introduction of fish species is a globally widespread practice that causes losses of native species and homogenization of diversity within and across continents. Diet assessments are important tools to depict the ecological function of species introduced into novel ecosystem and possible direct and indirect ecological effects. In this study, we compare the diet of Piaractus brachypomus, a mainly frugivorous Neotropical fish, introduced into the Sepik-Ramu River Basin (Papua New Guinea) nearly two decades ago, to that of similar size individuals from Neotropical populations in the Amazon and Orinoco River basins (South America). In contrast to native populations that feed mainly on terrestrial plants and invertebrates, the diet of introduced P. brachypomus is mainly composed of fish remains and aquatic plants, while terrestrial plants are frequently consumed but in relatively smaller amounts. These findings show that P. brachypomus has an inherently plastic diet that can be adjusted when displaced to a novel geographic area. While trophic plasticity increases the likelihood of a species to establish breeding populations after its introduction, it also reduces our ability to predict negative effects on native species.(AU)

La introducción de peces es una práctica que se extiende globalmente y que causa perdida de especies nativas y homogenización de la diversidad dentro y entre continentes. Los estudios de dieta son herramientas útiles para definir la función ecológica de una especie introducida en un ecosistema nuevo y los posibles efectos directos e indirectos. En este estudio describimos la dieta de Piaractus brachypomus, una especie de pez Neotropical principalmente frugívora, que fue introducida en el río Sepik (Papua Nueva Guinea) hace casi dos décadas; y la comparamos con aquella de individuos de tamaño corporal similar de poblaciones nativas en las cuencas de los ríos Amazonas y Orinoco (América del Sur). En contraste con las poblaciones nativas que se alimentan principalmente de frutas y semillas, plantas e invertebrados terrestres, la dieta de individuos de P. brachypomus introducidos se compone principalmente de restos de peces y plantas acuáticas, mientras que plantas terrestres son consumidas frecuentemente pero en pequeñas cantidades. Estos resultados indican que P. brachypomus tiene una dieta plástica que puede adaptarse cuando la especie se desplaza a un área geográfica nueva. A pesar de que la plasticidad trófica aumenta la probabilidad de que una especie establezca poblaciones reproductivas después de la introducción, también reduce nuestra habilidad de predecir los efectos negativos sobre especies nativas.(AU)

Assuntos

RESUMO

Species of peacock bass were introduced in several watersheds in South America and worldwide, mainly due to its importance to sport fishing, by being a fighting fish. A recent revision of the genus Cichla showed that the species introduced in reservoirs of the South, Southeast and Northeast regions of Brazil are two new species, described as Cichla kelberi (yellow peacock bass) and Cichla piquiti (blue peacock bass), erroneously identified as C. monoculus and C. ocellaris. With the purpose to identify the populations of Cichla in Paranapanema and Paraná rivers, a total of 323 base pairs (bp) of the mtDNA control region were sequenced, obtained from 84 specimens of Cichla in six different localities (Tapajós river, Solimões river, Capivara, Taquaruçu and Rosana reservoirs in the Paranapanema river, and in the upper Paraná river floodplain). The analyses revealed the genetic diversity of Cichla monoculus, introduced into the Capivara reservoir, originally from the region of Manaus (Amazonas State), and spread in the reservoirs downstream (Taquaruçu and Rosana). The occurrence of the same haplotypes in the three reservoirs suggests one single introduction. This study confirmed the introduction of Cichla in the Capivara reservoir and showed the genetic diversity of Cichla in the Paranapanema river.

Espécies de tucunaré foram introduzidas em inúmeras bacias hidrográficas da América do Sul e em outras regiões do planeta, principalmente pelas suas características esportivas, de peixe lutador. Revisão recente das espécies do gênero Cichla mostraram que as espécies que foram introduzidas nos reservatórios das regiões Sul, Sudeste e Nordeste, são duas espécies novas, descritas como Cichla kelberi (tucunaré amarelo) e Cichla piquiti (tucunaré azul) identificadas erroneamente como C. monoculus e C. ocellaris. Com o objetivo de identificar as populações de Cichla presentes no rio Paranapanema e Paraná, foram sequenciadas um total de 323 pares de bases (pb) da região controle (mtDNA) obtidas de 84 espécime de Cichla em seis localidades diferentes (rio Tapajós, rio Solimões, Reservatórios de Capivara, Taquaruçu, Rosana localizados no rio Paranapanema e na bacia do alto rio Paraná. Os dendrogramas e as análises das populações revelaram fortes evidências de que Cichla monoculus foi introduzida no reservatório de Capivara, proveniente da região de Manaus e se dispersou para os reservatórios localizados a jusante (Taquaruçu e Rosana). A ocorrência dos mesmos haplótipos nos três reservatórios sugerem uma única introdução. Este trabalho confirma a introdução de Cichla no reservatório de Capivara e revela a diversidade genética das espécies presentes no rio Paranapanema.

Assuntos

RESUMO

Species of peacock bass were introduced in several watersheds in South America and worldwide, mainly due to its importance to sport fishing, by being a fighting fish. A recent revision of the genus Cichla showed that the species introduced in reservoirs of the South, Southeast and Northeast regions of Brazil are two new species, described as Cichla kelberi (yellow peacock bass) and Cichla piquiti (blue peacock bass), erroneously identified as C. monoculus and C. ocellaris. With the purpose to identify the populations of Cichla in Paranapanema and Paraná rivers, a total of 323 base pairs (bp) of the mtDNA control region were sequenced, obtained from 84 specimens of Cichla in six different localities (Tapajós river, Solimões river, Capivara, Taquaruçu and Rosana reservoirs in the Paranapanema river, and in the upper Paraná river floodplain). The analyses revealed the genetic diversity of Cichla monoculus, introduced into the Capivara reservoir, originally from the region of Manaus (Amazonas State), and spread in the reservoirs downstream (Taquaruçu and Rosana). The occurrence of the same haplotypes in the three reservoirs suggests one single introduction. This study confirmed the introduction of Cichla in the Capivara reservoir and showed the genetic diversity of Cichla in the Paranapanema river.(AU)

Espécies de tucunaré foram introduzidas em inúmeras bacias hidrográficas da América do Sul e em outras regiões do planeta, principalmente pelas suas características esportivas, de peixe lutador. Revisão recente das espécies do gênero Cichla mostraram que as espécies que foram introduzidas nos reservatórios das regiões Sul, Sudeste e Nordeste, são duas espécies novas, descritas como Cichla kelberi (tucunaré amarelo) e Cichla piquiti (tucunaré azul) identificadas erroneamente como C. monoculus e C. ocellaris. Com o objetivo de identificar as populações de Cichla presentes no rio Paranapanema e Paraná, foram sequenciadas um total de 323 pares de bases (pb) da região controle (mtDNA) obtidas de 84 espécime de Cichla em seis localidades diferentes (rio Tapajós, rio Solimões, Reservatórios de Capivara, Taquaruçu, Rosana localizados no rio Paranapanema e na bacia do alto rio Paraná. Os dendrogramas e as análises das populações revelaram fortes evidências de que Cichla monoculus foi introduzida no reservatório de Capivara, proveniente da região de Manaus e se dispersou para os reservatórios localizados a jusante (Taquaruçu e Rosana). A ocorrência dos mesmos haplótipos nos três reservatórios sugerem uma única introdução. Este trabalho confirma a introdução de Cichla no reservatório de Capivara e revela a diversidade genética das espécies presentes no rio Paranapanema.(AU)

Assuntos

RESUMO

Palms are distinctive plants of tropics and have peculiar allometric relations. Understanding such relations is useful in the case of introduced species because their ability to establish and invade must be clarified in terms of their responses in the new site. Our purpose was to assess the survival and invasive capacity of an introduced palm species in the Atlantic rainforest, Euterpe oleracea Mart., compared to the native Euterpe edulis Mart. and to the hybrids produced between the two species. Considering this, we compared the allometry in different ontogenetic stages, the germination rates, and aspects of the initial development. The ontogenetic stages proposed for both Euterpe illustrated the growth patterns described for palm trees. E. oleracea and hybrids adjusted to the geometric similarity allometric model, while E. edulis presented a slope greater than would be expected considering this model, indicating a greater height for a given diameter. E. oleracea showed the same amount of pulp per fruit as E. edulis and a similar initial development of seedlings. The main differences observed were a lower germination rate and a faster height gain of E. oleracea seedlings. We conclude that E. oleracea, which is similar to E. edulis in aspects of allometry, development, seed and seedling morphology, may be an important competitor of this native palm tree in the Atlantic Forest.

Palmeiras são plantas características dos trópicos que apresentam relações alométricas peculiares. Compreender tais padrões pode ser útil no caso de espécies introduzidas, uma vez que sua habilidade de estabelecimento e invasão deve ser esclarecida em relação as suas respostas à nova localidade. Nosso propósito foi compreender a sobrevivência e a capacidade de invasão de uma palmeira introduzida na floresta Atlântica, Euterpe oleracea Mart. (açaizeiro) comparada à palmeira nativa Euterpe edulis Mart. (juçara), também considerando seus híbridos. Para isso comparamos suas relações alométricas em estádios ontogenéticos, sua germinação e seu desenvolvimento inicial. Os estádios ontogenéticos propostos para ambas as Euterpe ilustraram os padrões de crescimento esperados para palmeiras. E. oleracea e híbridos apresentaram-se sob o modelo alométrico de similaridade geométrica e E. edulis apresentou inclinação maior do que este modelo. E. oleracea produziu a mesma quantidade de polpa por fruto que E. edulis. As principais diferenças observadas foram menor taxa de germinação e maior velocidade de crescimento em altura para as plântulas de E. oleracea. Em conclusão, nossos resultados indicam que E. oleracea, sendo similar a E. edulis em termos de alometria, desenvolvimento e morfologia de sementes e plântulas, pode ser um importante competidor para a espécies nativa na Floresta Atlântica.

Assuntos

RESUMO

This study assessed the coexistence of three species of thraira present in the Upper Paraná River floodplain, using population structure as an investigation tool. The species were designated as: Hoplias sp. 1, introduced after the construction of the Itaipu reservoir, and Hoplias sp. 2 and Hoplias sp. 3, native species that have been identified as Hoplias aff. malabaricus. We tested the hypothesis that those species in fact differ from each other in respect of population abundance, sex ratio, relative frequency of adults and juveniles, length structure and weight-length relationship. Additionally, possible effects of the flood pulse on the first four of these parameters were investigated. Samples were collected quarterly from March 2006 to December 2007 from nine collection sites on the floodplain. Hoplias sp. 1 presented a greater balance of sex ratio and length structures over the seasons, as well as a higher allometric coefficient. The population attributes of Hoplias sp. 2 and Hoplias sp. 3 showed a high responsiveness to hydrological seasonality, indicating that these species exploit available resources in a conspicuous flood period with greater efficiency. These differences, beyond reflecting possible mechanisms that allow closely related species to coexist, indicate the importance of understanding the life strategies adopted by each species which, as part of a complex system, are considered key elements of the aquatic community structure in the region, providing important information for habitat management and biodiversity conservation.

RESUMO

The improvement of natural pastures was consolidated in the highlands of Santa Catarina State only recently when a great area of improved natural pastures already existed. Technology adopted by farmers was due to its increase in fodder production and stocking capacity. Besides, this technology presented costs inferior to the ones for conventional pasture cultivation. However, this technology still needs a more rigorous evaluation, which is to be achieved by three on farm experiments, conducted in Campo Belo do Sul county. It was evaluated forage production and quality, animal liveweight gain (LWG) and the profitability of the native pasture improvement technology. The average results were as follows: the pastures showed an in vitro OMD of 66.1; 62.6; 72.4 and 66.5%, during summer, autumn, winter and spring season, respectively. The crude protein content was of 14.7; 19.7; 22.0 and 14.4% for the same season order. Animal LWG of 511, 63 kg ha-1 year-1 , with a daily animal LWG of 0.789 kg animal-1 day-1 and animal stocking of 648 kg of LW ha-1. Finally, the system showed an economic gross margin of R$ 811,10 ha-1 (U$ 477,00 ha-1).

O melhoramento de pastagens naturais foi consolidado na Serra Catarinense a partir da segunda metade da década de 90. Nesta época já existia uma grande área implantada, como resultado da adoção por diversos produtores, em função do aumento da produção de forragem, da elevação da capacidade de suporte, como também dos custos de implantação serem inferiores aos praticados em cultivos convencionais. Apesar da dimensão existente, esta tecnologia ainda necessitava de avaliação e acompanhamento mais rigorosos. Assim, foram conduzidos três ensaios de validação no município de Campo Belo do Sul, por um período de três anos, nos quais se avaliou a produção e qualidade da forragem, o rendimento animal e a rentabilidade econômica. Os resultados médios obtidos foram: 511,63 kg peso vivo (PV) ha-1 ano-1, sendo o granho médio diário (GMD) de 0,789 kg animal-1 dia-1 e carga animal de 648 kg de PV ha-1. A digestibilidade in vitro da matéria orgânica (DIVMO) foi de 66,1; 62,6; 72,4 e 66,5%, no verão, outono, inverno e primavera, respectivamente. O teor de proteína bruta foi de 14,7; 19,7; 22,0 e 14,4% para a mesma ordem das estações do ano. A margem bruta foi de R$ 811,10 ha-1.

RESUMO

Palms are distinctive plants of tropics and have peculiar allometric relations. Understanding such relations is useful in the case of introduced species because their ability to establish and invade must be clarified in terms of their responses in the new site. Our purpose was to assess the survival and invasive capacity of an introduced palm species in the Atlantic rainforest, Euterpe oleracea Mart., compared to the native Euterpe edulis Mart. and to the hybrids produced between the two species. Considering this, we compared the allometry in different ontogenetic stages, the germination rates, and aspects of the initial development. The ontogenetic stages proposed for both Euterpe illustrated the growth patterns described for palm trees. E. oleracea and hybrids adjusted to the geometric similarity allometric model, while E. edulis presented a slope greater than would be expected considering this model, indicating a greater height for a given diameter. E. oleracea showed the same amount of pulp per fruit as E. edulis and a similar initial development of seedlings. The main differences observed were a lower germination rate and a faster height gain of E. oleracea seedlings. We conclude that E. oleracea, which is similar to E. edulis in aspects of allometry, development, seed and seedling morphology, may be an important competitor of this native palm tree in the Atlantic Forest.

Palmeiras são plantas características dos trópicos que apresentam relações alométricas peculiares. Compreender tais padrões pode ser útil no caso de espécies introduzidas, uma vez que sua habilidade de estabelecimento e invasão deve ser esclarecida em relação as suas respostas à nova localidade. Nosso propósito foi compreender a sobrevivência e a capacidade de invasão de uma palmeira introduzida na floresta Atlântica, Euterpe oleracea Mart. (açaizeiro) comparada à palmeira nativa Euterpe edulis Mart. (juçara), também considerando seus híbridos. Para isso comparamos suas relações alométricas em estádios ontogenéticos, sua germinação e seu desenvolvimento inicial. Os estádios ontogenéticos propostos para ambas as Euterpe ilustraram os padrões de crescimento esperados para palmeiras. E. oleracea e híbridos apresentaram-se sob o modelo alométrico de similaridade geométrica e E. edulis apresentou inclinação maior do que este modelo. E. oleracea produziu a mesma quantidade de polpa por fruto que E. edulis. As principais diferenças observadas foram menor taxa de germinação e maior velocidade de crescimento em altura para as plântulas de E. oleracea. Em conclusão, nossos resultados indicam que E. oleracea, sendo similar a E. edulis em termos de alometria, desenvolvimento e morfologia de sementes e plântulas, pode ser um importante competidor para a espécies nativa na Floresta Atlântica.

RESUMO

This study assessed the coexistence of three species of thraira present in the Upper Paraná River floodplain, using population structure as an investigation tool. The species were designated as: Hoplias sp. 1, introduced after the construction of the Itaipu reservoir, and Hoplias sp. 2 and Hoplias sp. 3, native species that have been identified as Hoplias aff. malabaricus. We tested the hypothesis that those species in fact differ from each other in respect of population abundance, sex ratio, relative frequency of adults and juveniles, length structure and weight-length relationship. Additionally, possible effects of the flood pulse on the first four of these parameters were investigated. Samples were collected quarterly from March 2006 to December 2007 from nine collection sites on the floodplain. Hoplias sp. 1 presented a greater balance of sex ratio and length structures over the seasons, as well as a higher allometric coefficient. The population attributes of Hoplias sp. 2 and Hoplias sp. 3 showed a high responsiveness to hydrological seasonality, indicating that these species exploit available resources in a conspicuous flood period with greater efficiency. These differences, beyond reflecting possible mechanisms that allow closely related species to coexist, indicate the importance of understanding the life strategies adopted by each species which, as part of a complex system, are considered key elements of the aquatic community structure in the region, providing important information for habitat management and biodiversity conservation.

RESUMO

The improvement of natural pastures was consolidated in the highlands of Santa Catarina State only recently when a great area of improved natural pastures already existed. Technology adopted by farmers was due to its increase in fodder production and stocking capacity. Besides, this technology presented costs inferior to the ones for conventional pasture cultivation. However, this technology still needs a more rigorous evaluation, which is to be achieved by three on farm experiments, conducted in Campo Belo do Sul county. It was evaluated forage production and quality, animal liveweight gain (LWG) and the profitability of the native pasture improvement technology. The average results were as follows: the pastures showed an in vitro OMD of 66.1; 62.6; 72.4 and 66.5%, during summer, autumn, winter and spring season, respectively. The crude protein content was of 14.7; 19.7; 22.0 and 14.4% for the same season order. Animal LWG of 511, 63 kg ha-1 year-1 , with a daily animal LWG of 0.789 kg animal-1 day-1 and animal stocking of 648 kg of LW ha-1. Finally, the system showed an economic gross margin of R$ 811,10 ha-1 (U$ 477,00 ha-1).

O melhoramento de pastagens naturais foi consolidado na Serra Catarinense a partir da segunda metade da década de 90. Nesta época já existia uma grande área implantada, como resultado da adoção por diversos produtores, em função do aumento da produção de forragem, da elevação da capacidade de suporte, como também dos custos de implantação serem inferiores aos praticados em cultivos convencionais. Apesar da dimensão existente, esta tecnologia ainda necessitava de avaliação e acompanhamento mais rigorosos. Assim, foram conduzidos três ensaios de validação no município de Campo Belo do Sul, por um período de três anos, nos quais se avaliou a produção e qualidade da forragem, o rendimento animal e a rentabilidade econômica. Os resultados médios obtidos foram: 511,63 kg peso vivo (PV) ha-1 ano-1, sendo o granho médio diário (GMD) de 0,789 kg animal-1 dia-1 e carga animal de 648 kg de PV ha-1. A digestibilidade in vitro da matéria orgânica (DIVMO) foi de 66,1; 62,6; 72,4 e 66,5%, no verão, outono, inverno e primavera, respectivamente. O teor de proteína bruta foi de 14,7; 19,7; 22,0 e 14,4% para a mesma ordem das estações do ano. A margem bruta foi de R$ 811,10 ha-1.

RESUMO

This study assessed the coexistence of three species of thraira present in the Upper Paraná River floodplain, using population structure as an investigation tool. The species were designated as: Hoplias sp. 1, introduced after the construction of the Itaipu reservoir, and Hoplias sp. 2 and Hoplias sp. 3, native species that have been identified as Hoplias aff. malabaricus. We tested the hypothesis that those species in fact differ from each other in respect of population abundance, sex ratio, relative frequency of adults and juveniles, length structure and weight-length relationship. Additionally, possible effects of the flood pulse on the first four of these parameters were investigated. Samples were collected quarterly from March 2006 to December 2007 from nine collection sites on the floodplain. Hoplias sp. 1 presented a greater balance of sex ratio and length structures over the seasons, as well as a higher allometric coefficient. The population attributes of Hoplias sp. 2 and Hoplias sp. 3 showed a high responsiveness to hydrological seasonality, indicating that these species exploit available resources in a conspicuous flood period with greater efficiency. These differences, beyond reflecting possible mechanisms that allow closely related species to coexist, indicate the importance of understanding the life strategies adopted by each species which, as part of a complex system, are considered key elements of the aquatic community structure in the region, providing important information for habitat management and biodiversity conservation.

RESUMO

Three species of Sidneioides Kesteven, 1909 were known until now, all of them from the western Pacific. Sidneioides peregrinus is a new species we found in Paranaguá Bay, southern Brazil. Diagnostic characteristics of the species are: colonies with 1-5 lobes, closely clumped, and attached by the entire basal area or by a common smaller area; seven to ten thin longitudinal fiber muscles (some branched) along the anterior two thirds of the thorax; no transverse muscle fibers; more than 30 tentacles of three orders forming one circle; pharynx with 10 to 12 rows of stigmata with 13 to 15 stigmata in each half row; bilobed anus at the level of the fourth or fifth row of stigmata; posterior abdomen not very elongated, oval, and joined to the abdomen by a narrow neck; numerous (> 30) testicular follicles; ovary with about 15 oocytes at about the ninth or tenth row of stigmata in the thorax; large number of embryos incubated in the atrial cavity in the right side of the thorax; larvae oval with a 0.65 mm long trunk, four club-shaped ectodermal ampullae in each side and three, linear and evenly spaced, adhesive papillae with thin stalks, two clusters of ectodermal vesicles, one postero-ventral (around 15 vesicles) and another antero-dorsal (around eight vesicles) between the ampullae and the oral siphon. This paper describes this new species and reports its occurrence in Brazil, where it is most likely introduced. The hypothesis that it is introduced is based on 1) it was never found in previous surveys, 2) in Brazil, it has a restricted and local distribution, 3) its type locality is near a major international port, and 4) the genus, prior to this description, had never been found in the Atlantic Ocean. Considering the great abundance found on the underside of natural boulders, it is imperative that S. peregrinus population growth be studied to evaluate the possibility of rapid distribution expansion.

RESUMO

Three species of Sidneioides Kesteven, 1909 were known until now, all of them from the western Pacific. Sidneioides peregrinus is a new species we found in Paranaguá Bay, southern Brazil. Diagnostic characteristics of the species are: colonies with 1-5 lobes, closely clumped, and attached by the entire basal area or by a common smaller area; seven to ten thin longitudinal fiber muscles (some branched) along the anterior two thirds of the thorax; no transverse muscle fibers; more than 30 tentacles of three orders forming one circle; pharynx with 10 to 12 rows of stigmata with 13 to 15 stigmata in each half row; bilobed anus at the level of the fourth or fifth row of stigmata; posterior abdomen not very elongated, oval, and joined to the abdomen by a narrow neck; numerous (> 30) testicular follicles; ovary with about 15 oocytes at about the ninth or tenth row of stigmata in the thorax; large number of embryos incubated in the atrial cavity in the right side of the thorax; larvae oval with a 0.65 mm long trunk, four club-shaped ectodermal ampullae in each side and three, linear and evenly spaced, adhesive papillae with thin stalks, two clusters of ectodermal vesicles, one postero-ventral (around 15 vesicles) and another antero-dorsal (around eight vesicles) between the ampullae and the oral siphon. This paper describes this new species and reports its occurrence in Brazil, where it is most likely introduced. The hypothesis that it is introduced is based on 1) it was never found in previous surveys, 2) in Brazil, it has a restricted and local distribution, 3) its type locality is near a major international port, and 4) the genus, prior to this description, had never been found in the Atlantic Ocean. Considering the great abundance found on the underside of natural boulders, it is imperative that S. peregrinus population growth be studied to evaluate the possibility of rapid distribution expansion.