Geographic variation of Moenkhausia bonita (Characiformes: Characidae) in the rio de la Plata basin, with distributional comments on M. intermedia

Moenkhausia bonita occurs in numerous additional localities from the Bermejo, Paraná, Paraguay, and Uruguay river basins. Given that this finding greatly expands the distributional range of M. bonita, we carried out an intraspecific comparison, using multivariate methods for 18 morphometric and eight meristic characters taken from a comprehensive sample of 536 specimens. All localities were distributed in four major geographic groups as follows: Bermejo, Paraná, Paraguay, and Uruguay. Results of the morphometric comparisons showed significant differences among the studied groups except between the Paraguay and Uruguay groups. Statistical differences in meristic values were found for most between-group comparisons, especially in those resulting from discriminant canonical analyses (DCA). Specimens from the Bermejo basin were the most distinct group in most morphological comparisons. However, the overall subtle differences found in body morphology likely reflect intraspecific variation within M. bonita and seem to be mainly influenced by spatial and environmental features of drainages. As M. bonita was previously identified as M. intermedia in the río de La Plata basin, distributional comments on the latter species in that basin are provided.(AU)

Moenkhausia bonita es registrada en numerosas localidades adicionales de las cuencas de los ríos Bermejo, Paraná, Paraguay, y Uruguay. Dado que estos hallazgos expanden ampliamente el rango distribucional de M. bonita, nosotros llevamos a cabo una comparación intraespecífica, usando métodos multivariados para 18 características morfométricas y 8 merísticas que fueron tomados en una muestra exhaustiva de 536 especímenes. Todas las localidades fueron repartidas en cuatro grupos principales como sigue: Bermejo, Paraná, Paraguay y Uruguay. Los resultados de las comparaciones morfométricas mostraron diferencias significativas a través de los grupos bajo estudio, excepto entre los grupos Paraguay y Uruguay. Diferencias estadísticas fueron encontrados en la mayoría de las comparaciones entre los grupos, especialmente en aquellas obtenidas de los análisis discriminantes canónicos (ADC). Los especímenes de la cuenca del Bermejo fueron encontrados como el grupo más divergente en la mayoría de las comparaciones morfológicas. No obstante, estas leves diferencias encontradas en la morfología del cuerpo son consideradas dentro de la variación intraespecífica de M. bonita y parecen estar influidas por características ambientales y espaciales de los drenajes. Dado que M. bonita fue previamente identificada como M. intermedia en la cuenca del río de La Plata, comentarios distribucionales sobre esta última especie en esta cuenca son presentados.(AU)

Geographic variation of Moenkhausia bonita (Characiformes: Characidae) in the rio de la Plata basin, with distributional comments on M. intermedia

Moenkhausia bonita occurs in numerous additional localities from the Bermejo, Paraná, Paraguay, and Uruguay river basins. Given that this finding greatly expands the distributional range of M. bonita, we carried out an intraspecific comparison, using multivariate methods for 18 morphometric and eight meristic characters taken from a comprehensive sample of 536 specimens. All localities were distributed in four major geographic groups as follows: Bermejo, Paraná, Paraguay, and Uruguay. Results of the morphometric comparisons showed significant differences among the studied groups except between the Paraguay and Uruguay groups. Statistical differences in meristic values were found for most between-group comparisons, especially in those resulting from discriminant canonical analyses (DCA). Specimens from the Bermejo basin were the most distinct group in most morphological comparisons. However, the overall subtle differences found in body morphology likely reflect intraspecific variation within M. bonita and seem to be mainly influenced by spatial and environmental features of drainages. As M. bonita was previously identified as M. intermedia in the río de La Plata basin, distributional comments on the latter species in that basin are provided.(AU)

Moenkhausia bonita es registrada en numerosas localidades adicionales de las cuencas de los ríos Bermejo, Paraná, Paraguay, y Uruguay. Dado que estos hallazgos expanden ampliamente el rango distribucional de M. bonita, nosotros llevamos a cabo una comparación intraespecífica, usando métodos multivariados para 18 características morfométricas y 8 merísticas que fueron tomados en una muestra exhaustiva de 536 especímenes. Todas las localidades fueron repartidas en cuatro grupos principales como sigue: Bermejo, Paraná, Paraguay y Uruguay. Los resultados de las comparaciones morfométricas mostraron diferencias significativas a través de los grupos bajo estudio, excepto entre los grupos Paraguay y Uruguay. Diferencias estadísticas fueron encontrados en la mayoría de las comparaciones entre los grupos, especialmente en aquellas obtenidas de los análisis discriminantes canónicos (ADC). Los especímenes de la cuenca del Bermejo fueron encontrados como el grupo más divergente en la mayoría de las comparaciones morfológicas. No obstante, estas leves diferencias encontradas en la morfología del cuerpo son consideradas dentro de la variación intraespecífica de M. bonita y parecen estar influidas por características ambientales y espaciales de los drenajes. Dado que M. bonita fue previamente identificada como M. intermedia en la cuenca del río de La Plata, comentarios distribucionales sobre esta última especie en esta cuenca son presentados.(AU)

A contribution for the limnological knowledge of basaltic knickzones / Uma contribuição para o conhecimento limnológico dos pedrais basálticos

The knickzones are defined as locally steep riverbed segments, such as a convex reach in a concave-up longitudinal profile. They are worldwide distributed and geologically well studied, but despite their distinctiveness as a particular kind of macrohabitat there is a notorious lack of ecological knowledge. In this context, this research proposal aims to provide a physical description, in terms of kind of habitats, and a limnological characterization of a basaltic knickzone. Information is based on a case study carried out in the Sapucaí-Mirim River, Southeast Brazil. Samplings were performed in three different habitats well represented in the knickzone (runs, riffles and pools) during rainy and dry conditions. A clear discrimination in terms of habitat type and seasonality was demonstrated through a principal component analysis. Pools exhibited higher amplitude of variation for most limnological parameters when compared to runs and riffles, probably due to a great influence of the internal metabolism (photosynthetic production and community respiration). Despite of their geological ancient formation and the little understanding of their ecological role, the knickzones are in imminent threat in several regions of the world by hydropower dams implementation. The lack of ecological information on knickzones is probably due to inherent access difficulties and how to compare the distinct kinds of habitats. Thereby, further studies should be encouraged.(AU)

Os pedrais são definidos como segmentos de rio com leito localmente íngreme, tais como um alcance convexo em um perfil longitudinal côncavo. Eles são mundialmente distribuídos e geologicamente bem estudados, mas apesar de sua distinção como um tipo particular de macrohabitat há uma notória falta de conhecimento ecológico. Neste contexto, a proposta desta pesquisa é fornecer uma descrição física, em termos de tipo de habitats, e uma caracterização limnológica de um pedral basáltico. A informação é baseada em um estudo de caso realizado no rio Sapucaí-Mirim, no Sudeste do Brasil. As amostragens foram realizadas em três diferentes habitats bem representados na zona de pedral (rápidos, corredeiras e poças) durante as condições chuvosa e seca. Uma clara discriminação em termos de tipo de habitat e sazonalidade foi demonstrada através de uma análise de componentes principais. As poças apresentaram maior amplitude de variação para a maioria dos parâmetros limnológicos quando comparadas aos rápidos e corredeiras, provavelmente devido a grande influência do metabolismo interno (produção fotossintética e respiração das comunidades). Apesar de sua formação geológica antiga e da pouca compreensão de seu papel ecológico, os pedrais estão em ameaça iminente em várias regiões do mundo pela implementação de barragens hidrelétricas. A falta de informações ecológicas sobre os pedrais é provavelmente devido às dificuldades inerentes de acesso e como comparar os tipos distintos de habitats. Assim, devem ser encorajados novos estudos.(AU)

Hydro-physical characterization of soils under the Restinga Forest

ABSTRACT: Knowledge of the hydraulic properties of the soil is of crucial importance to an understanding of the interactions between vegetation, soil and water. There is little information available about the hydraulic properties of Podzol soils found in tropical regions. The aim of this study was to present the soil morphology and hydraulic properties of a toposequence situated in a permanent plot at the Ilha do Cardoso State Park (Cananéia, SP, Brazil). Ultradetailed soil maps were used to define a toposequence inside the permanent plot. Five profiles, representing the main types of soil, were opened along the toposequence, in which Podzols are dominant. The levels of bulk density, sand content, porosity and permeability in these soils were all high. Consequently, these soils have a high level of hydraulic conductivity with low water retention. This behavior undergoes an alteration in the Bh and Bs horizons due to the accumulation of organic and metallic compounds and a changing structure that modifies the pore distribution. Furthermore, the characterization of the hydro-physical functioning of soils in natural environments is an important source of encouragement to further investigative study of soil water dynamics and its relationship to the native vegetation.

Hydro-physical characterization of soils under the Restinga Forest

ABSTRACT: Knowledge of the hydraulic properties of the soil is of crucial importance to an understanding of the interactions between vegetation, soil and water. There is little information available about the hydraulic properties of Podzol soils found in tropical regions. The aim of this study was to present the soil morphology and hydraulic properties of a toposequence situated in a permanent plot at the Ilha do Cardoso State Park (Cananéia, SP, Brazil). Ultradetailed soil maps were used to define a toposequence inside the permanent plot. Five profiles, representing the main types of soil, were opened along the toposequence, in which Podzols are dominant. The levels of bulk density, sand content, porosity and permeability in these soils were all high. Consequently, these soils have a high level of hydraulic conductivity with low water retention. This behavior undergoes an alteration in the Bh and Bs horizons due to the accumulation of organic and metallic compounds and a changing structure that modifies the pore distribution. Furthermore, the characterization of the hydro-physical functioning of soils in natural environments is an important source of encouragement to further investigative study of soil water dynamics and its relationship to the native vegetation.(AU)

Geomorphometric tool associated with soil types and properties spatial variability at watersheds under tropical conditions

The application of quantitative methods to digital soil and geomorphological mapping is becoming an increasing trend. One of these methods, Geomorphons, was developed to identify the ten most common landforms based on digital elevation models. This study aimed to make a quantitative assessment of the relationships between Geomorphons units, determined at three spatial resolutions and nine radii, and soil types and properties of two watersheds with different soil-landscape relationships in Brazil to help soil surveying and mapping under tropical conditions. The study was conducted at Lavrinha Creek (LCW) and Marcela Creek (MCW) watersheds, located in the state of Minas Gerais, Brazil. Spatial resolutions of 10, 20 and 30 m were the basis for generating Geomorphons at 9 radii of calculation for the watersheds. They were overlapped to detailed soil maps of the watersheds and a chi-square test was carried out to assess their relationship with soil types. Observation points were compared with the most highly correlated Geomorphons to also assess relationships with soil properties. Geomorphons with resolution of 30-m and radii of 20 and 50 cells, respectively for LCW and MCW, were more highly correlated with the variability of soil types, in accordance with the terrain features of these watersheds. The majority of observation points for each soil type was located in the same Geomorphon unit that was dominant when analyzing soil maps. There was less variability in soil properties between Geomorphon units, which was probably due to the highly weathered-leached stage of soils. Geomorphons can help to improve soil maps in tropical conditions when assessing soil variability due to its high correlation with tropical soil types variability.

Geomorphometric tool associated with soil types and properties spatial variability at watersheds under tropical conditions

The application of quantitative methods to digital soil and geomorphological mapping is becoming an increasing trend. One of these methods, Geomorphons, was developed to identify the ten most common landforms based on digital elevation models. This study aimed to make a quantitative assessment of the relationships between Geomorphons units, determined at three spatial resolutions and nine radii, and soil types and properties of two watersheds with different soil-landscape relationships in Brazil to help soil surveying and mapping under tropical conditions. The study was conducted at Lavrinha Creek (LCW) and Marcela Creek (MCW) watersheds, located in the state of Minas Gerais, Brazil. Spatial resolutions of 10, 20 and 30 m were the basis for generating Geomorphons at 9 radii of calculation for the watersheds. They were overlapped to detailed soil maps of the watersheds and a chi-square test was carried out to assess their relationship with soil types. Observation points were compared with the most highly correlated Geomorphons to also assess relationships with soil properties. Geomorphons with resolution of 30-m and radii of 20 and 50 cells, respectively for LCW and MCW, were more highly correlated with the variability of soil types, in accordance with the terrain features of these watersheds. The majority of observation points for each soil type was located in the same Geomorphon unit that was dominant when analyzing soil maps. There was less variability in soil properties between Geomorphon units, which was probably due to the highly weathered-leached stage of soils. Geomorphons can help to improve soil maps in tropical conditions when assessing soil variability due to its high correlation with tropical soil types variability.(AU)

Use of functional traits to assess changes in stream fish assemblages across a habitat gradient

Functional traits are important for understanding the links between species occurrence and environmental conditions. Identifying these links makes it possible to predict changes in species composition within communities under specific environmental conditions. We used functional traits related to habitat use and trophic ecology in order to assess the changes in fish community composition between streams with varying habitat structure. The relationship between the species traits and habitat characteristics was analyzed using an RLQ ordination analysis. Although species were widely distributed in habitats with different structures, physical conditions did favor some species based on their functional characteristics. Eight functional traits were found to be associated with stream habitat structure, allowing us to identify traits that may predict the susceptibility of fish species to physical habitat degradation.(AU)

Os atributos funcionais são importantes para entender a ligação entre ocorrência das espécies e condições ambientais, permitindo predizer sobre as mudanças na composição de espécies em comunidades submetidas a condições ambientais específicas. Utilizamos atributos funcionais relacionados com o uso de habitat e ecologia trófica para avaliar as mudanças na composição de espécies de peixes em riachos com diferenças na estrutura física. O relacionamento entre os atributos das espécies e as variáveis ambientais foi avaliado por meio da análise de ordenação RLQ. Embora algumas espécies tenham sido amplamente distribuídas em hábitats com diferentes características, outras foram restritas por essas condições e este relacionamento está associado com as características morfológicas. Oito atributos funcionais foram capazes de detectar as variações na estrutura física do hábitat em riachos, permitindo a identificação de atributos que podem predizer a suscetibilidade das espécies de peixes para a degradação física do hábitat.(AU)

Influence of light on the initial growth of invasive Cryptostegia madagascariensis Bojer in the Brazilian semiarid region / Influência da luz no crescimento inicial da invasora Cryptostegia madagascariensis Bojer no semiárido Brasileiro

The invasion by Cryptostegia madagascariensis causes economic and environmental problems in Northeastern Brazil. Current study evaluates the initial growth of C. madagascariensis on light gradient. The experiment used 0, 30, 50 and 70% shading treatments arranged in a completely randomized design and evaluated in four periods, namely, 35, 50, 65 and 80 days. Height, absolute growth rate, relative growth rate, number of side branches, number of leaves, leaf area, specific leaf area, leaf area ratio, root mass ratio, stem mass ratio, leaf mass ratio and leaf area/root mass ratio were evaluated. Results showed that the height was greater in shade environments, and the greater the available light, the greater was the number of side branches. C. madagascariensis is able to change the leaf area, specific leaf area and biomass allocation in different shadings. Since C. madagascariensis varies growth forms and performs morphological adjustments to increase light uptake, the plant has warranted success during the initial growth under different shadings.(AU)

A invasão da Cryptostegia madagascariensis causa problemas econômicos e ambientais no Nordeste do Brasil. O objetivo do trabalho foi estudar o crescimento inicial da C. madagascariensis em gradiente de luz. O experimento utilizou os tratamentos de 0, 30, 50 e 70% de sombreamento, dispostos em um delineamento experimental inteiramente casualizado e avaliados em quatro períodos: 35, 50, 65 e 80 dias. Foram avaliados a altura, a taxa de crescimento absoluto, a taxa de crescimento relativo, o número de ramos laterais e de folhas, a área foliar, a área foliar específica, a razão de área foliar, a razão de massa da raiz, a razão de massa do caule, a razão de massa das folhas e a razão área foliar/massa da raiz. Os resultados mostraram que a altura foi maior em ambientes sombreados e, quanto mais luz disponível, maior o número de ramos laterais. A C. madagascariensis é capaz de alterar a área foliar, a área foliar específica e na alocação de biomassa nos diferentes sombreamentos. Portanto, a C. madagascariensis varia a forma de crescimento e realiza ajustes morfológicos para aumentar a captação de luz, o que garantiu seu sucesso durante o crescimento inicial em diferentes sombreamentos.(AU)

A frota pesqueira costeira do estado do Rio de Janeiro / Fishing fleet in the coastal zone of the state of Rio de Janeiro

The fishing activity in the state of Rio de Janeiro is reflected in a fleet formed, mostly, by vessels poorly sized and older. Taking into account the lack of knowledge about the state of the coastal fleet Rio de Janeiro, the present study aimed to characterize the vessels; identify sub-fleets presents; describe and compare these fleets and seek to understand the role of environmental, socioeconomic and cultural characteristics on the spatial arrangement of the vessels. For the study, the structural characteristics of the vessels were collected along the coastal physiographic compartments of Rio de Janeiro, composing a total of 1,879 vessels, described and analyzed the role of the environment on the spatial distribution and characterization. Data analysis showed that although environmental characteristics have formed distinct groups among physiographic compartments, these did not correspond to differences between fleets, which suggest that the environment is not the sole determinant of the type of vessel. Other factors that affect are historical and socioeconomic aspects. The absence of policies to stimulate the construction and modernization of vessels allows that the Rio de Janeiros fleet is currently described as old and obsolete, when compared to other coastal fleets in the Southeast and South of Brazil.(AU)

A situação da atividade pesqueira no estado do Rio de Janeiro é refletida em uma frota composta, em sua maioria, por embarcações mal dimensionadas e antigas. Levando em consideração o pouco conhecimento sobre a frota pesqueira fluminense, o presente estudo teve como objetivos: caracterizar as embarcações; identificar subfrotas presentes ao longo do estado do Rio de Janeiro; descrever e comparar tais frotas e buscar entender o papel das características ambientais, socioeconômicas e culturais sobre a disposição espacial das embarcações. Para realização do estudo, dados sobre as características estruturais das embarcações foram coletados ao longo dos compartimentos fisiográficos do litoral do Estado, compondo um total de 1.879 embarcações, descritas e analisadas quanto ao papel do ambiente na distribuição espacial e caracterização. A análise dos dados mostrou que, embora características ambientais tenham formado grupos distintos entre os compartimentos fisiográficos, estas não corresponderam a diferenças entre as frotas, o que sugere que o ambiente não é o único fator condicionante do tipo de embarcação. Outros fatores que interferem são os aspectos históricos e socioeconômicos. A ausência de políticas de incentivo à construção e modernização das embarcações permite que, atualmente, a frota fluminense seja qualificada como antiga e obsoleta quando comparada às outras frotas costeiras das regiões Sudeste e Sul do Brasil.(AU)

Seasonal and spatial variations in limnological conditions of a floodplain lake (lake Catalão) connected to both the Solimões and Negro Rivers, Central Amazonia / Variações espaciais e temporais nas condições limnológicas de um lago de planície de inundação (lago Catalão) conectado aos rios Solimões e Negro, Amazônia Central

Lakes play an important role in biogeochemical, ecological and hydrological processes in the river-floodplain system. The aim of this study was to evaluate the dynamics of the limnological conditions of Catalمo Lake, an Amazon floodplain lake. Thus, some of the main limnological environment variables (O2, temperature, pH, nutrient, electrical conductivity) of the Catalمo Lake were analyzed under temporal and spacial scales. The study was conducted between November/2004 and August/2005. Sampling excursion were carried out every three months; one excursion for each of the four different hydrological periods (low water, rising water, high water and falling water). Sampling points were chosen so that it could be obtained a gradient of the distance from Negro River. Limnological profiles in Catalمo Lake showed generally acidic to slightly alcaline water, with low levels of dissolved oxygen and low concentrations of soluble reactive phosphorous. The Negro River seems to exert the main influence during the rising water period, while the Solimُes River is the principal controlling river during peak water. The Principal Component Analysis (PCA) grouped the seasonal collections by hydrological period, showing the formation of a north-south spatial gradient within the lake in relation to the limnological variables. Multivariate dispersion analysis based on distance-to-centroid method demonstrated an increase in similarity over the course of the hydrological cycle, as the lake was inundated in response to the flood pulse of the main river channels. However, the largest spatial homogeneity in the lake was observed in the epilimnion layer, during the falling water period. The daily analysis of variation indicated an oligomitic pattern during the years in which the lake was permanently connected to the Negro River...

Os lagos exercem um papel importante nos processos biogeoquímicos, ecológicos e hidrológicos no sistema rio-planície de inundação. O objetivo do presente estudo foi avaliar a dinâmica das condições limnológicas do lago Catalão, um lago da planície de inundação amazônica. Algumas das principais variáveis limnológicas (por exemplo, O2, temperatura, pH, condutividade elétrica, nutrientes) do lago Catalão foram analisadas em uma escala temporal e espacial. O presente estudo foi realizado no período de novembro de 2004 a agosto de 2005. As amostragens foram trimestrais, com um total de quatro coletas, uma em cada fase do ciclo hidrológico (Seca, Enchente, Cheia e Vazante). Os pontos de amostragem foram escolhidos de modo a obter um gradiente de distância em relação ao rio Negro. No geral, as águas do lago Catalão mostraram-se pouco oxigenadas, ácidas a levemente alcalinas e com baixas concentrações de Fósforo Solúvel Reativo (FSR). A Análise de Componentes Principais (ACP) agrupou as estações de coleta por fases do ciclo hidrológico e evidenciou a formação de um gradiente espacial na distribuição das variáveis limnológicas, que vai da região mais ao norte até mais ao sul do lago. A influência do rio Negro sobre as águas do lago parece ser maior na enchente e a do rio Solimões na cheia. A análise de dispersão multivariada com abordagem baseada na distância ao centróide evidenciou o aumento da similaridade espacial em função da inundação. Contudo, a maior homogeneidade espacial do lago foi registrada no epilímnio, na fase de vazante. Os resultados da análise de variação diária indicaram que o lago Catalão apresenta comportamento oligomítico nos anos em que permanece conectado permanentemente ao rio Negro. Apesar de receber grande aporte de águas pretas (rio Negro) e brancas (rio Solimões), as características físicas e químicas das águas do Catalão permitem classificá-lo como um sistema mais próximo dos lagos de várzea típicos do que daqueles de águas preta.

Seasonal and spatial variations in limnological conditions of a floodplain lake (lake Catalão) connected to both the Solimões and Negro Rivers, Central Amazonia / Variações espaciais e temporais nas condições limnológicas de um lago de planície de inundação (lago Catalão) conectado aos rios Solimões e Negro, Amazônia Central

Lakes play an important role in biogeochemical, ecological and hydrological processes in the river-floodplain system. The aim of this study was to evaluate the dynamics of the limnological conditions of Catalمo Lake, an Amazon floodplain lake. Thus, some of the main limnological environment variables (O2, temperature, pH, nutrient, electrical conductivity) of the Catalمo Lake were analyzed under temporal and spacial scales. The study was conducted between November/2004 and August/2005. Sampling excursion were carried out every three months; one excursion for each of the four different hydrological periods (low water, rising water, high water and falling water). Sampling points were chosen so that it could be obtained a gradient of the distance from Negro River. Limnological profiles in Catalمo Lake showed generally acidic to slightly alcaline water, with low levels of dissolved oxygen and low concentrations of soluble reactive phosphorous. The Negro River seems to exert the main influence during the rising water period, while the Solimُes River is the principal controlling river during peak water. The Principal Component Analysis (PCA) grouped the seasonal collections by hydrological period, showing the formation of a north-south spatial gradient within the lake in relation to the limnological variables. Multivariate dispersion analysis based on distance-to-centroid method demonstrated an increase in similarity over the course of the hydrological cycle, as the lake was inundated in response to the flood pulse of the main river channels. However, the largest spatial homogeneity in the lake was observed in the epilimnion layer, during the falling water period. The daily analysis of variation indicated an oligomitic pattern during the years in which the lake was permanently connected to the Negro River...(AU)

Os lagos exercem um papel importante nos processos biogeoquímicos, ecológicos e hidrológicos no sistema rio-planície de inundação. O objetivo do presente estudo foi avaliar a dinâmica das condições limnológicas do lago Catalão, um lago da planície de inundação amazônica. Algumas das principais variáveis limnológicas (por exemplo, O2, temperatura, pH, condutividade elétrica, nutrientes) do lago Catalão foram analisadas em uma escala temporal e espacial. O presente estudo foi realizado no período de novembro de 2004 a agosto de 2005. As amostragens foram trimestrais, com um total de quatro coletas, uma em cada fase do ciclo hidrológico (Seca, Enchente, Cheia e Vazante). Os pontos de amostragem foram escolhidos de modo a obter um gradiente de distância em relação ao rio Negro. No geral, as águas do lago Catalão mostraram-se pouco oxigenadas, ácidas a levemente alcalinas e com baixas concentrações de Fósforo Solúvel Reativo (FSR). A Análise de Componentes Principais (ACP) agrupou as estações de coleta por fases do ciclo hidrológico e evidenciou a formação de um gradiente espacial na distribuição das variáveis limnológicas, que vai da região mais ao norte até mais ao sul do lago. A influência do rio Negro sobre as águas do lago parece ser maior na enchente e a do rio Solimões na cheia. A análise de dispersão multivariada com abordagem baseada na distância ao centróide evidenciou o aumento da similaridade espacial em função da inundação. Contudo, a maior homogeneidade espacial do lago foi registrada no epilímnio, na fase de vazante. Os resultados da análise de variação diária indicaram que o lago Catalão apresenta comportamento oligomítico nos anos em que permanece conectado permanentemente ao rio Negro. Apesar de receber grande aporte de águas pretas (rio Negro) e brancas (rio Solimões), as características físicas e químicas das águas do Catalão permitem classificá-lo como um sistema mais próximo dos lagos de várzea típicos do que daqueles de águas preta.(AU)

Ownership of fishing areas and use of fishing resources by artisanal fishermen in a pond in southern Brazi / Apropriação de áreas de pesca e utilização dos recursos pesqueiros por pescadores artesanais em uma lagoa no sul do Brasil

The Mangueira Lagoon located in southern Brazil, has its northern portion included in the Taim Ecological Station, a federal conservation unit. The fishing practice is among the activities at this region. It has its own characteristics due to environmental conditions and specific physiography of the area. A field protocol based on geographic information was used to characterize the occupation process and the use of fishing resources. Socio-economic information was collected through interviews of the fishermen and also based on fishing data. After compiling the data a statistical descriptive analyses was completed. The average catch per fisherman in the region is 4,766.5 kg per year. The Loricariichthys anus showed the highest catch volume, ensuring the economic viability of the local activity. The constant increase of the activity may be compromising the reproductive cycle of the local ichthyological fauna, thus compromising the fishery sustainability.(AU)

A Lagoa Mangueira localizada no sul do Brasil tem sua porção norte incluída na Estação Ecológica do Taim, unidade de conservação federal. Entre os usos dados a esta região, destacase a pesca artesanal, que apresenta caracteristicas próprias devido as condições ambientais e fisiográficas da região. Com objetivo de caracterizar o processo de ocupação e uso dos recursos pesqueiros, foi usado um protocolo de campo e de informação geográfica. Dados de pesca foram coletados e entrevistas foram aplicadas para obter informações sócio-econômicas, que foram tabulados e submetidos à análise estatística descritiva. A captura média por pescador na região é de 4.766,5 kg/ano, sendo a viola Loricariichthys anus a espécie com maior volume de captura, garantindo a viabilidade econômica da pesca local. O aumento contínuo do esforço de pesca pode estar comprometendo o ciclo reprodutivo da fauna ictiológica local, comprometendo a sustentabilidade da pesca.(AU)