ABSTRACT
We aimed to access the knowledge of the structure of the periphytic algae community on a floating substrate, the macrophyte Ricciocarpus natans (L.) Corda, during two hydrological periods in a connected environment at the Paraná river floodplain. Attached algal was removed from the substrate with the aid of a soft-bristled brush and distilled water jets and was fixed immediately for qualitative and quantitative analysis. The total richness of the periphytic algae was 188 taxa. February showed the highest species richness (154 taxa), while total species density exhibited an inverse pattern, with the highest values occurring in June (273.4 103ind. cm-2). Bacillariophyceae comprised the largest fraction of density, which was reflected by the abundance of Achnanthidium minutissimum (Kütz.) Czarn. Community structure of periphytic algae in R. natans followed the same pattern of other substrates, as previously determined. This suggests that main factor acting on the structure of periphyton at the Paraná river floodplain is primarily the floodpulses regime. The hydrochoric dispersion of R. natans across the various environments comprising the floodplain favors its communities associated, as the periphytic algae, subject to passive transport via water movement. Floating rhizoids of R. natans also may act as a mesh retainer, promoting the colonization of many metaphytic and planktonic s
ABSTRACT
The aim of this study is to evaluate the kinetics of aerobic decomposition of Saccharum officinarum and Talauma ovata leaves. For each species, decomposition chambers (leaves and water) were set up, which were maintained under controlled conditions. Each sampling day (1, 7, 15, 30, 39, 58, 72 and 90 days), the concentrations of total organic carbon, pH and electrical conductivity (EC) were determined in the dissolved fraction, while the mass and cell wall fractions (CWF) were determined in the particulate fraction. The pH stabilization of the chambers with T. ovata and S. officinarum leaves occurred in alkaline (ca. 8 - 8.5) and close to the neutrality (ca. 7 - 7.5) environment, respectively. The EC values were on average 1.6 times higher in incubations with T. ovata leaves. The mass loss did not differ between the species (mean = 53.85%), however the decay coefficient was higher for S. officinarum (k4 = 0.007 day-1) than for T. ovata (k4 = 0.005 day-1) leaves. The CWF mass loss (mean = 50.16%) and their coefficient (0.0090 day-1) were similar. S. officinarum decomposed faster due to its high concentrations of energetic compounds of interest to the microbiota. The slower decomposition of T. ovata may have occurred due to the presence of secondary compounds with negative effects to the microorganisms.
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The objective of the present study was to investigate the influence of domestic sewage on the water along the Camandocaia River. The limnological variables analyzed were: pH, turbidity, color, manganese, iron, dissolved oxygen, nitrogen and total phosphorus. The data are discussed in terms of average values, and the Principal Component Analysis was employed. At no point were the oxygen saturation values below 70%, with the exception of point 9 (38.8%). The lowest nitrogen values were detected in points 1 to 3 (0.18 to 0.21 mg L-1) and the highest in points 9 and 10 (1.29 and 1.79 mg L-1); the highest phosphorus value was detected in point 9 (345.5 µg L-1). All variables correlate positively to the principal component 1, with the exception of oxygen saturation. The sum of the two principal components explains 86.6% of total variation found. The water of the river was little impacted by domestic sewage until Amparo. The highest levels of pollution were detected at the end of that city, and the trend was partial self-depuration until confluence with the Jaguary River. Nevertheless, the most polluted point of the river, when compared to other polluted rivers, presented lower pollution levels.
Investigar a influência do esgoto orgânico na água do rio Camandocaia. Foram analisadas as seguintes variáveis limnológicas: pH, turbidez, cor, manganês, ferro, oxigênio dissolvido, nitrogênio e fósforo totais. Os dados são discutidos em termos de valores médios e foi aplicada a Análise de Componentes Principais. Em nenhum dos 12 pontos estudados, os valores de saturação de oxigênio estiveram abaixo de 70%, com exceção do Ponto 9 (38,8%). Os menores valores de nitrogênio foram detectados nos Pontos 1 a 3 (0,18 a 0,21 mg L-1) e os valores mais elevados nos Pontos 9 e 10 (1,29 e 1,79 mg L-1); o valor mais elevado de fósforo foi detectado no Ponto 9 (345,5 µg L-1). Todas as variáveis correlacionam-se positivamente ao componente principal 1, com exceção da saturação de oxigênio. Os dois componentes principais somados explicam 86,6% do total da variação encontrada. A água do Camandocaia foi pouco impactada pelos esgotos até Amparo. No final dessa cidade foram detectados os níveis mais elevados de poluição, e a tendência foi a depuração parcial do esgoto até a confluência com o rio Jaguari. Entretanto, o local mais poluído do rio, quando comparado a outros rios poluídos, apresentou níveis de poluição inferiores.
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The present study aimed to inventory of bats species present in an urban area, located within the main campus of the State University of Maringá, northwestern Paraná State, and to present data on the diet, reproduction, and activity times of the captured species. Collections were performed monthly, between September 2007 and August 2008, and 377 individuals were captured, belonging to four species from the Phyllostomidae family: Artibeus lituratus (90%), Platyrrhinus lineatus (6.4%), Sturnira lilium (2.4%), and Carollia perspicillata (1.3%). The types of fruit ingested consisted especially of Cecropiaceae, Moraceae, Myrtaceae, Piperaceae and Solanaceae. Among the captured exemplars, 51% were female and 49% male. No pregnant females of A. lituratus or males with descended testicles were captured in autumn, and the largest recorded numbers of these groups were verified in winter. With regard to lactating females, A. lituratus was sampled year-round, with predominance during the warmer season. In spite of the low species diversity, the campus area is used by frugivore species that are generalists and are able to feed and reproduce in urbanized areas. In order to increase that diversity, management programs should be implemented so that urbanization and Chiroptera diversity can coexist with lower risks and losses to ecosystems.
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This work aimed to study the structure of functional groups of entomofauna associated to aquatic macrophytes in Correntoso river, Rio Negro sub-region, Pantanal, Mato Grosso do Sul State, Brazil. Six samples were taken in different seasonal periods; ebb, dry and wet. The organisms were collected using D net (300 m mesh), sweeping five times through the roots of macrophyte banks at each sample session. Three environments were compared (open, intermediary, close) using data from six collection sites, through which were analyzed absolute abundance, observed richness of families and the sampled specimens were also separated in functional groups. A total of 60 families from 12 orders of Insecta were registered, totaling 19,773 sampled insects. The largest number of families was categorized into predators functional group, with 34 families collected, followed by the collectors with 17, shredders-herbivores ten and scrapers eight.
ABSTRACT
The present study investigates the 13C and 15N isotopic composition in frozen samples (control), samples in alcohol and in formaldehyde of Plagioscion squamosissimus and Hypophthalmus edentates. From each individual we extracted a strip of muscle from the region above the lateral line, in the dorsal fin base, that was divided into three equal parts, each one was submitted to one type of treatment: freeze control group (-15oC), conservation in alcohol 70% and fixation in formaldehyde 4%. Samples were kept under those treatments for 30 days, washed and submerged in distilled water for 4 hours. Afterwards, they were dried up in air oven at 60oC for 48 hours and macerated until the obtaining of a fine powder. A significant difference was found in isotopic values of carbon and nitrogen, between the control and the samples in alcohol and formaldehyde, except for 13C from the H. edentates samples in formaldehyde. The carbon isotopic values of samples in alcohol were mostly enriched compared to control, whereas the samples in formaldehyde presented depleted values in relation to the control. The nitrogen isotopic values for both samples preserved in alcohol and formaldehyde were enriched when compared to the values of frozen samples, independently of used preservatives. Therefore, the isotopic correction should be accomplished according to the isotope and preservative employed for
The present study investigates the 13C and 15N isotopic composition in frozen samples (control), samples in alcohol and in formaldehyde of Plagioscion squamosissimus and Hypophthalmus edentates. From each individual we extracted a strip of muscle from the region above the lateral line, in the dorsal fin base, that was divided into three equal parts, each one was submitted to one type of treatment: freeze control group (-15oC), conservation in alcohol 70% and fixation in formaldehyde 4%. Samples were kept under those treatments for 30 days, washed and submerged in distilled water for 4 hours. Afterwards, they were dried up in air oven at 60oC for 48 hours and macerated until the obtaining of a fine powder. A significant difference was found in isotopic values of carbon and nitrogen, between the control and the samples in alcohol and formaldehyde, except for 13C from the H. edentates samples in formaldehyde. The carbon isotopic values of samples in alcohol were mostly enriched compared to control, whereas the samples in formaldehyde presented depleted values in relation to the control. The nitrogen isotopic values for both samples preserved in alcohol and formaldehyde were enriched when compared to the values of frozen samples, independently of used preservatives. Therefore, the isotopic correction should be accomplished according to the isotope and preservative employed for
ABSTRACT
The floodplain of the upper Paraná river is characterized by the great diversity of aquatic organisms, and the larvae of Chironomidae are distinguished for their high density. Starting from the hypothesis that abiotic variables influence Chironomidae larvae composition, density and dominance in different environments and sampled periods, this study aimed to characterize the Baía river, secondary channel, floodplain lakes (connected and non-connected) of the Paraná river floodplain, according to attributes of Chironomidae assemblage, and identify possible gradients of temporal and spatial distribution of the larvae, relating them with abiotic variables. The collections were carried out from March 2003 to December 2005. Samples were collected in three points (margins and center), using a modified Petersen grab. CCA showed the larvae were influenced mainly by sediment particle size. Curutuba channel, due to the presence of pebbles, differed from other sites such as the Baía river and floodplain lakes, where fine particles predominated. It was concluded that particle size composition, percentage of organic matter and hydrodynamic of each environment were the main variables that influenced the spatial distribution of Chironomidae larvae.
A planície de inundação do alto rio Paraná caracteriza-se pela grande diversidade de organismos aquáticos e as larvas de Chironomidae destacam-se por sua elevada abundância. A partir da hipótese de que as variáveis abióticas influenciam a composição, densidade e dominância das larvas de Chironomidae em diferentes ambientes e períodos amostrados, este trabalho objetivou: caracterizar o rio Baía, canal secundário, lagoa não-conectada (Fechada) e lagoa conectada (Guaraná) da planície de inundação do alto rio Paraná, de acordo com os atributos da assembléia de Chironomidae e identificar possíveis gradientes de distribuição espacial e temporal das larvas, relacionando-as com algumas variáveis abióticas. As coletas foram realizadas no período de março de 2003 a dezembro de 2005, em três pontos distintos (margens e centro), com o auxílio de um pegador tipo Petersen modificado. A Análise de Correspondência Canônica mostrou que as larvas foram influenciadas principalmente pela textura granulométrica do sedimento. O canal Curutuba, pela presença de seixos, diferenciou-se das demais estações de coleta como rio Baía e as lagoas de inundação onde predominaram as partículas mais finas. Pode-se concluir que a composição granulométrica, a porcentagem de matéria orgânica presente no sedimento e a hidrodinâmica de cada ambiente foram os principais fatores que influenciaram a distribuição espacia
ABSTRACT
This work aimed ato research the distribution of insects associated with aquatic macrophytes and the similarity among collection sites during the reflux period in a stretch of Correntoso river, Pantanal do Negro, Mato Grosso do Sul State, Brazil. The collection sites were determined by changes in the riparian formation structure, characterized as open when there is communication with flooded fields and intermediary and closed when there is not any communication with flooded fields. Three collections were taken at six sample sites, during reflux periods. The organisms were collected using a D net, 300 µm mesh, with samples from five nets thrown in roots of aquatic macrophytes. Family richness, absolute and relative abundance of the insects found, and similarity of collection sites were analyzed using Euclidian distance and complete connection, Shannon-Wiener diversity index, with log2. Sixty-four families from 10 orders of Hexapoda class were registered, totaling 2,525 individuals 2,405 of them aquatic and semi- aquatic, and 120 terrestrial. The collect sites did not present a fixed model of similarity, and the formation of groups occurred in distinct forms at each collection.
Este trabalho teve como objetivo pesquisar a distribuição de insetos associados a macrófitas aquáticas e a similaridade dos sítios de coleta, no período de vazante, em um trecho do rio Correntoso, Pantanal do Negro, Estado do Mato Grosso do Sul, Brasil. Os sítios de coleta foram determinados conforme a mudança na estrutura da formação ripária, caracterizados como abertos com comunicação com campos inundáveis; intermediários sem comunicação com campos inundáveis; fechados sem comunicação com campos inundáveis. Foram realizadas três coletas durante o período de vazante, em seis sítios de coletas. Os organismos foram coletados utilizando rede D com malha de 300 µm e esforço amostral de cinco lances de rede em raízes de macrófitas aquáticas. Foi analisada a riqueza de famílias, a abundância absoluta e relativa dos insetos encontrados, a similaridade dos sítios de coleta por análise de agrupamento, utilizando distância euclidiana e ligação completa, índice de diversidade de Shannon-Wienner, com log2. Foram registradas 64 famílias de dez ordens da Classe Hexapoda, totalizando 2.525 indivíduos, 2.405 aquáticos e semi-aquáticos e 120 terrestres. Os sítios de coleta não apresentaram padrão fixo de similaridade, e a formação dos grupos ocorreu de forma distinta a cada coleta.
ABSTRACT
The objective of this study was to evaluate the impacts of fire on the tree-shrub component in an ombrophilous forest fragment in Areia, state of Paraíba, Brazil. Forty parcels were plotted in two environments: intact forest (Environment I) and burned forest (Environment II). The vegetation structure was evaluated by conventional parameters, and the difference in the number of shoots of individuals between the environments was evaluated using the Kruskal-Wallis test. Also calculated were the index of diversity, equability and the similarity between the environments. We sampled 1,960 individuals, belonging to 22 families, 26 genera and 35 species. In Environment I, Protium heptaphyllum, Cupania oblongifolia and Brosimum guianense were the most important and abundant species, while the dead individuals were the majority in Environment II. The Kruskal-Wallis test showed there were significant differences between the intact and burned environments. The indices of diversity and the equability of Environment I were greater than those found in Environment II. Nevertheless, the two environments remain similar according to the Jaccard index. The results showed that fire does not appear to change the composition of species; however, it affected the structure of the community, and increased significantly the number of shoots, indicating the death of the canopy in several individuals
O objetivo do presente trabalho foi avaliar os impactos causados pelo fogo sobre o estrato arbustivo-arbóreo de um fragmento de Floresta Atlântica, em Areia, Paraíba. Foram plotadas 40 parcelas de 100 m2 em dois ambientes: floresta intacta (Ambiente I) e floresta queimada (Ambiente II). O presente levantamento incluiu indivíduos com diâmetro ao nível do solo (DNS) 3 cm, sendo a estrutura da vegetação avaliada por parâmetros convencionais. Calcularam-se, também, os índices de diversidade e de equabilidade, além da similaridade entre os ambientes. Foram amostrados 1.960 indivíduos, pertencentes a 22 famílias, 26 gêneros e 35 espécies. No Ambiente I, Protium heptaphyllum foi a espécie mais abundante e importante; no Ambiente II, sobressaíram-se os indivíduos mortos. O teste Kruskal-Wallis (H) analisou a diferença no número de perfilhos dos indivíduos entre os Ambientes, apontando diferença significativa entre estes. O índice de diversidade e a equabilidade no Ambiente I foram maiores que no atingido pelo incêndio; pelo índice de Jaccard, porém, verificou-se que continuam similares. Os resultados demonstraram que o incêndio parece não modificar a composição específica da sinúsia, mas afeta a estrutura da comunidade, além de aumentar significativamente o perfilhamento, indicando a morte da parte aérea de muitos indivíduos
ABSTRACT
In Brazil, studies on the diet of Chironomidae larvae are still scarce and these data are important to understand the trophic structure and organization of aquatic ecosystems. In this study, we identified the main food items consumed by Cricotopus sp. and compared possible differences in the larval diet at different artificial substrates and hydrological phases. We used four types of artificial substrates: X-shaped wood (MADX); X-shaped nitacetal plates (NITX); tube-shaped PVC (PVCT) and tube-shaped galvanized metal (METT), each with three replicates. Samplings were undertaken fortnightly, between August 2004 and December 2005. Cricotopus sp. diet was composed by detritus, algae and fungal hyphae. Detritus was the main food item, with values above 50% of total intake. The results indicated that Cricotopus sp. is a collector species and, regardless of substrate, these larvae feed on available resources in the environment. However, the changes in hydrological regime of the Paraná river can influence the food resource availability, mainly some Diatoma genera such as Melosira sp., which were consumed in high quantity only during the low water phase
No Brasil, estudos sobre hábitos alimentares das larvas de Chironomidae ainda são escassos e estas informações são importantes para entender a estrutura trófica e a organização dos ecossistemas aquáticos. Neste estudo, teve-se como objetivo identificar os principais itens alimentares ingeridos por Cricotopus sp. e comparar as possíveis diferenças na dieta das larvas em diferentes substratos artificiais e fases hídricas. Foram utilizados quatro tipos de substratos artificiais: madeira em forma de X (MADX), placas de nitacetal em forma de X (NITX), PVC em forma de tubo (PVCT) e metal galvanizado em forma de tubo (METT), cada um com três réplicas. As coletas foram realizadas quinzenalmente, entre os meses de agosto de 2004 e dezembro de 2005. A dieta de Cricotopus sp. foi constituída por detritos, algas e hifas de fungos. Detrito foi o principal item alimentar, com valores superiores a 50% do total consumido. Os resultados indicaram que Cricotopus sp. é uma espécie coletora e, independentemente do substrato, as larvas alimentam-se dos recursos disponíveis no ambiente. Entretanto, mudanças no regime hidrológico do rio Paraná podem influenciar a disponibilidade de alimento, principalmente algumas diatomaceas como Melosira sp., consumidas em maior quantidade apenas na fase de águas baixas
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The dynamic of plant communities is strongly influenced by biological interactions. We studied the effects of Eichhornia azurea on the growth of the free-floating macrophytes Eichhornia crassipes, Salvinia minima, Salvinia auriculata and Limnobium laevigatum. The experiments were carried out in three lakes of the upper Paraná river floodplain. We used 0.5 m side squares where these species grew for 11 days (S. auriculata and L. laevigatum) and 17 days (E. crassipes and S. minima), in the presence and absence of E. azurea. There were no significant differences between the relative growth rates of macrophytes growing in the absence and presence of E. azurea. The relative interaction index showed the existence of competition between E. azurea and L. laevigatum, and neutrality with the other three species. There was no evidence of facilitation related to the improvement of physico-chemistry characteristics that could enhance macrophytes growth. However, we do not discard a mechanical facilitation between E. azurea, which offers protection against wind and waves, and the other species of macrophytes
ABSTRACT
This study aimed at establishing the adequate concentrations of nitrapyrin for effective inhibition of oxygen demand required by nitrogen compounds oxidation during aerobic mineralization of the leachate. The aquatic macrophyte Myriophyllum aquaticum was used as dissolved organic matter (DOM) source. The leachate was incubated in several chambers which contained different composition and treatments: (i) treatment with leachate (DOM), (ii) treatment with DOM plus nitrapyrin in different concentrations (10 mg L-1; 25 mg L-1 and 50 mg L-1), aiming at finding the right concentration that inhibits nitrification process, (iii) treatment with DOM plus NH4SO2 (iv) treatment containing DOM and nitrapyrin plus NH4SO2 and (v) treatment with DOM plus azide. The dissolved oxygen amount in each treatment of incubations was periodically measured. The results indicated that the ratio of 10 mg L-1 of nitrapyrin for each 10 mg C of leachate is efficient in inhibition of the oxidation of nitrogen compounds from aquatic macrophytes.
Este estudo visou estabelecer as concentrações adequadas da nitrapirina para a inibição das demandas de oxigênio produzidas pelas oxidações dos compostos nitrogenados durante a mineralização aeróbia de lixiviado, utilizando a macrófita aquática Myriophyllum aquaticum como fonte de matéria orgânica dissolvida (MOD). Para tanto, realizaram-se incubações com lixiviado com diferentes tratamentos: (i) tratamento com MOD, (ii) tratamento com MOD + nitrapirina em diferentes concentrações (10 mg L-1; 25 mg L-1 e 50 mg L-1), visando encontrar a concentração que inibisse o processo de nitrificação, (iii) tratamento com MOD + NH4SO2, (iv) tratamento com MOD + NH4SO2 + nitrapirina, e (v) tratamento com MOD + azida. A partir destas incubações, foram efetuadas medições periódicas da quantidade de oxigênio dissolvido destes tratamentos. Os resultados indicaram que a proporção de 10 mg L-1 de nitrapirina para cada 10 mg C de lixiviado é eficaz para inibir a oxidação dos compostos nitrogenados de lixiviados de macrófitas aquáticas.
ABSTRACT
The upper Paraná river floodplain possesses a great diversity of rotifers, with 288 planktonic taxa recorded. Surveys performed in this ecosystem since 1992 have shown that Lecanidae is the most abundant family, with 45 registered taxa. The main goal of the present study was to investigate the occurrence of this family in environments that have not yet been studied. Seven new occurrences of Lecane were recorded in plankton samples: L. bifurca, L. rhytida, L. subtilis, L. crepida, L. bulla styrax, L. obtusa, and L. thienemanne. Although the described taxa were found in plankton, this family is characterized by being typically non-planktonic. As such, exclusively taxonomic studies must explore the great habitat heterogeneity in this floodplain, e.g., the littoral region and the extensive areas colonized by aquatic macrophytes, aiming to expand knowledge on the diversity of this family in the upper Paraná river floodplain.
planície de inundação do alto rio Paraná possui grande diversidade de rotíferos, com 288 táxons planctônicos registrados. Estudos realizados, nesse ecossistema, desde 1992, mostram que Lecanidae é a família mais especiosa, com 45 táxons registrados. Este trabalho teve como objetivo investigar a ocorrência dessa família em ambientes ainda não-estudados e consequentemente contribuir para a diversidade de rotíferos nessa planície de inundação. Foram registradas sete novas ocorrências de Lecane em amostras do plâncton: L. bifurca, L. rhytida, L. subtilis, L. crepida, L. bulla styrax, L. obtusa, e L. thienemanne. Embora os táxons descritos fossem encontrados no plâncton, essa família caracteriza-se por ser tipicamente não-planctônica. Dessa forma, visando ampliar o conhecimento sobre a diversidade dessa família na planície de inundação do alto rio Paraná, estudos exclusivamente taxonômicos devem explorar a grande heterogeneidade de hábitats presente nessa planície, como, por exemplo, a região marginal e as extensas áreas colonizadas por macrófitas aquáticas.
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The objective of this work is to describe the morphological characteristics of seven Northern Pantanal lakes and discuss their implications on the limnology of these environments. The following morphological parameters were used: area; volume; maximum, mean and relative depths; perimeter; volume and perimeter development indices; maximum length and width. Generally, most lakes are shallow, with low relative depths, suggesting little thermal stratification, as they are more susceptible to mixing of the water column and suspended sediments by wind action. Most lakes have regular banks (few irregularities) and have a concave shape, and thus are less subject to erosion processes. Temporal variations in the morphometry of these lakes are related to the hydrodynamic and limnological patterns of these systems.
O presente trabalho tem como objetivo descrever as características morfométricas de sete lagoas do Pantanal Norte e discutir suas implicações na limnologia deste ambientes. Os parâmetros utilizados foram: área, volume, profundidades máxima, média e relativa, perímetro, índices de desenvolvimento de volume e perímetro, comprimento e largura máxima. De modo geral, as maiorias das lagoas são rasas com pequenas profundidades relativas, assim menos propensas a estratificações térmicas e mais susceptíveis a ação dos ventos que atua como agente na resuspensão de matéria e mistura da coluna de água. Apresentam margens pouco irregulares e forma da bacia côncava que são menos influenciadas pelos processos de a erosão e sedimentação. Variações temporais na morfometria das lagoas conseqüentemente afetam os padrões hidrodinâmicos e limnológicos destes sistemas.
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The length-weight relationship and condition factor for Cichla kelberi introduced in an artificial lake in southeastern Brazil were analyzed. By studying separately the male, female and immature individuals, different length-weight patterns were found to happen among them. The same happened when distinct seasonal variations were compared. They are related to feeding alterations and the reproductive periods. The length-weight relationship and condition factor for these fishes vary in accordance with the time of introduction, population size, the characteristics of the ecosystem, sexual maturity, as well as the intra- and interspecific interactions.
Analisou-se a relação peso-comprimento e o fator de condição de Cichla kelberi introduzido em um lago artificial do Sudeste brasileiro. Imaturos, fêmeas e machos possuem padrões diferentes quanto à relação peso-comprimento e quanto às variações sazonais do fator de condição, que estão relacionadas às alterações de intensidade da atividade alimentar e ao período reprodutivo. Assim, a relação peso-comprimento e o fator de condição variam de acordo com tempo de introdução, tamanho da população, características dos ecossistemas, as interações intra e interespecíficas e maturidade sexual.
ABSTRACT
The aim of this study was to characterize the early development of Hoplias aff. malabaricus. The sampling was conducted during the period from November 1991 through February 1995, at 42 stations distributed in different environments of the upper Paraná river floodplain, Brazil. The specimens were taken from limnetic and littoral regions. Specimens were separated according to their development in larval (preflexion, flexion and postflexion stages) and juvenile periods. Morphometric and meristic variables were analyzed in 269 larvae and 74 juveniles (standard length ranging from 6.17 mm to 49.12 mm). Larvae showed fusiform body and intense pigmentation, a long intestine, large eyes and terminal mouth. Number of myomeres ranged from 37 to 45 (23-28 pre and 11-18 post-anal). The juveniles presented a body shape similar to their adults. The numbers of fin rays were: pectoral, 12; pelvic, 7-9; dorsal, 13-15; and anal, 10-12. Analysis of the growth showed metamorphosis in the early development of this species.
Este trabalho teve por objetivo caracterizar o desenvolvimento inicial de Hoplias aff. malabaricus. As amostragens foram realizadas entre novembro de 1991 e fevereiro de 1995, em 42 estações de coleta, distribuídas em vários ambientes da planície alagável do alto rio Paraná, Brasil. Para a obtenção do material, foram realizadas amostragens nas regiões pelágica (rede de plâncton) e litorânea (peneirão). Para a caracterização das diferentes fases, os indivíduos foram separados em períodos larval (estágios de pré-flexão, flexão e pós-flexão) e juvenil. Foram analisadas as variáveis morfométricas e merísticas em 269 larvas e 74 juvenis, com comprimento padrão variando entre 6,17 e 49,12 mm. As larvas apresentaram corpo fusiforme e altamente pigmentado, olhos grandes, intestino longo e boca terminal. O número total de miômeros variou de 37 a 45 (23 a 28 pré e 11 a 18 pós-anal). Os juvenis apresentaram a forma do corpo semelhante a do adulto. O número de raios das nadadeiras encontrado para a espécie foi: peitoral 12; pélvica 7-9; dorsal 13-15; e anal 10-12. A análise do crescimento indicou a metamorfose no início do desenvolvimento desta espécie.
ABSTRACT
Snails can become an environmental and economic problem, causing substantial losses. The objective of this work was to estimate the acute toxicity of copper sulfate pentahydrate (CuSO4.5H2O) and the aqueous extract of dried neem leaves on snails (P. canaliculata) under laboratory conditions. In order to estimate the lethal concentration 50% (LC (I)50;96h), snails were exposed to six increasing copper sulfate concentrations (0.0; 0.01; 0.03; 0.05; 0.07 and 0.1 mg L-1) and six increasing concentrations of aqueous extract of dried neem leaves 0.0; 100; 125; 150; 175 and 200 mL aqueous extract of dried neem leaves L-1 water, equivalent to (0.0; 1.18; 1.47; 1.77; 2.06; and 2.36 mg azadirachtin L-1), in triplicate and one control treatment in an entirely random delineation. Estimated LC (I)(50;96h) of copper sulfate was 0.02 mg copper sulfate L-1, with a 0.01 mg L-1 lower limit and a 0.03 mg L-1 upper limit. Estimated lethal concentration 50% of the aqueous extract of dried neem leaves was 142.75 mL L-1, equivalent to 1.68 mg L-1 of azadirachtine, with a 130.89 mL L-1 (1.54 mg L-1) low limit and 155.69 mL L-1 (1.83 mg L-1) as the upper limit.
Os caramujos podem se tornar um problema ambiental e econômico, podendo causar muitos prejuízos. O trabalho teve como objetivo estimar a toxicidade aguda do sulfato de cobre pentaidratado (CuSO4.5H2O) e do extrato aquoso de folhas secas de nim para o P. canaliculata, em condição de laboratório. Para determinação da CL (I)(50;96h), o caramujo foi exposto a seis concentrações crescentes de sulfato de cobre (0,0; 0,01; 0,03; 0,05; 0,07 e 0,1 mg L-1) e a seis concentrações crescentes de extrato aquoso de folhas secas de nim (0,0; 100; 125; 150; 175 e 200 mL de extrato aquoso de folhas secas de nim L-1 de água), equivalente a 0,0; 1,18; 1,47; 1,77; 2,06; e 2,36 mg de azadiractina L-1, com três repetições e um tratamento-controle em um experimento no delineamento inteiramente casualizado (DIC). A CL (I)(50;96h) estimada para o caramujo foi de 0,07 mg de sulfato de cobre L-1, com limite inferior de 0,05 mg L-1 e limite superior de 0,1 mg L-1. A concentração letal 50% (CL (I)50;96h) estimada do extrato aquoso de folhas secas de nim (EAFSN) para o caramujo foi de 142,75 mL L-1, equivalente a 1,68 mg L-1 de azadiractina, com limite inferior de 130,89 mL L-1 (1,54, mg L-1) e limite superior de 155,69 mL L-1 (1,83 mg L-1).
ABSTRACT
In fragmented landscapes, large distances from seed sources and strong soil degradation raises difficulties for colonization of new species in reforested areas and in early secondary forests. In this context, the artificial enrichment of reforestation areas with advanced successional level species is vital for the ecosystem sustainability. Methods like transference of soil and litter from mature forests and direct seeding may be alternatives. In this work, samples of surface soil and litter were distributed and nine non-pioneer native species were sowed in two reforestation areas and lab controls. From litter germinated 14 species in the control area: seven tree, three herb, two liana and two shrub species. Tree species were mostly from pioneer species, therefore of limited interest to enrichment purposes. However the non-arboreal species, important in the diversity of forest ecosystems, represented more than half of the individuals sampled. In the direct seeding experiment, Achatocarpus pubescens and Cordia ecalyculata displayed good results, despite the heterogeneity and Diospyros brasiliensis showed best germination rate (near 50%). The results suggests that further studies are needed on how the season of collection of soil and litter and the weather affects seed germination and seedling emergence.
Em paisagens fragmentadas, a colonização por novas espécies em reflorestamentos e capoeiras é dificultada pelas grandes distâncias das fontes de propágulos e a alta degradação do solo. Neste contexto, o enriquecimento artificial de reflorestamentos com espécies nativas de níveis sucessionais mais avançados torna-se imprescindível para garantir a sustentabilidade do ecossistema. Métodos como a transferência de serapilheira e solo de florestas maduras e a semeadura direta podem ser alternativas. Amostras de serapilheira e solo foram distribuídas em duas áreas de reflorestamento e uma área-controle, e nove espécies nativas não-pioneiras foram semeadas diretamente nas mesmas áreas e em dois controles. Da serapilheira, germinaram 14 espécies no controle: sete arbóreas, três herbáceas, duas lianescentes e duas arbustivas. As árvores são na maioria pioneiras e, portanto, de interesse limitado para o enriquecimento. Entretanto, as espécies não-arbóreas, importantes na diversidade de ecossistemas florestais, representaram metade dos indivíduos catalogados. Na semeadura direta, a espécie mais interessante foi Diospyros brasiliensis, com taxas de germinação de 50%. Achatocarpus pubescens e Cordia ecalyculata apresentaram resultados expressivos, apesar de heterogêneos. Os resultados mostram que são necessários estudos sobre a época de coleta da serapilheira e a influência do clima na germi
ABSTRACT
The length-weight relationship and condition factor of Salminus hilarii were analyzed in a section of the lower part of the Sorocaba river basin, São Paulo State. By studying male, female and immature individuals separately, different length-weight patterns were found for each. The same happened when distinct seasonal variations of the relationships were compared, related to feeding alterations and to the reproductive period of the species.
Foram analisados a relação peso-comprimento e o fator de condição de Salminus hilarii, em um trecho da parte baixa da bacia do rio Sorocaba, Estado de São Paulo. Machos, fêmeas e imaturos apresentaram diferentes relações peso-comprimento, assim como variações sazonais de condição que estão possivelmente relacionadas às alterações na intensidade da atividade alimentar e ao período reprodutivo.
ABSTRACT
We investigated the annual movements of feral Africanized honey bee (Apis melliferaL.) colonies in the state of Ceará, Brazil, aiming to understand seasonal variations in their population. Arrival and absconding of Africanized honey bee (AHB) colonies in the semiarid municipality of Canindé and the coastal humid city of Fortaleza (120 km apart) were recorded weekly from January 1999 to December 2001, and the data compared to rainfall records in both areas. Results showed that AHB colonies only nest in the semiarid during the rainy season and abscond during the dry season, the opposite from observations taken in Fortaleza. Only 5% of colonies remained in the semiarid area for the entire year due to ant (Camponotus sp.) attacks and shortage of nectar and water during the dry season, with most colonies migrating to coastal areas where the weather is milder and many plant species bloom at that time of year. Excessive rainfall probably pushes AHB colonies back to the semiarid during the rainy season. We concluded that absconding and migration are strategies that allow AHB colonies to survive in the semiarid NE of Brazil, contrary to European honeybees, which have never succeeded in establishing wild colonies in the region.
Os movimentos de colônias silvestres da abelha melífera africanizada (Apis mellifera L.) no Estado do Ceará, Brasil, foram investigados com o objetivo de compreender variações anuais em sua população. A chegada e a partida de colônias de abelhas africanizadas (AHB), no município semi-árido de Canindé e na úmida cidade litorânea de Fortaleza (separadas por 120 km), foram monitoradas semanalmente, de janeiro de 1999 a dezembro de 2001, e comparados com os dados pluviométricos de chuvas em ambas as áreas. Os resultados demonstraram que as abelhas africanizadas somente nidificaram no semi-árido durante a estação chuvosa e o abandonaram na estação seca, ao contrário do observado em Fortaleza. Apenas 5% das colônias permaneceram na área semi-árida por todo o ano, por causa dos ataques de formigas (Camponotus sp.) e carência de néctar e água na estação seca. A maioria das colônias migrou para as áreas litorâneas onde o clima é mais ameno e muitas espécies vegetais florescem nesta época do ano. O excesso de chuvas provavelmente forçava as colônias africanizadas a migrarem de volta ao semi-árido durante a estação chuvosa. Conclui-se que o abandono e a migração são estratégias que permitem às abelhas africanizadas sobreviverem no semi-árido nordestino, em contraste com as raças européias que nunca conseguiram estabelecer populações silvestres na região.