Spatial and Temporal Distribution of Trace Metals in Shallow Marine Sediments of the Yucatan Shelf, Gulf of Mexico.

We investigated the spatial and temporal distribution of V and Cd in surface sediments of the Yucatan Shelf to establish current average values for the area. V and Cd concentrations are similar to those reported internationally for limestone rocks and surface marine sediments. The observed variability of V concentrations between cruises may be the result of changes in ocean current direction in summer (SW-S) and strong prevailing winds in autumn (N-NE). In addition to the hydrodynamics described above, Cd variations may also be associated with inputs of particulate material by upwelling events and subsequent transport and distribution to the shelf by the Yucatan Channel current (autumn). Considering that both metals showed significant spatial and temporal differences, a range of values for V (0.4-1.5 µg g-1) and Cd (0.05-0.2 µg g-1) are proposed as baseline reference for sediments of the Yucatan Shelf.

Spatial and temporal distribution of the invasive lionfish Pterois volitans in coral reefs of Tayrona National Natural Park, Colombian Caribbean.

The lionfish Pterois volitans is an invasive species throughout the Western Atlantic that disturbs functioning of local ecosystems such as coral reefs via fast and intense consumption of small fish and invertebrates. In 2009, lionfish populated the bays of Tayrona National Natural Park (TNNP), a biodiversity hotspot in the Colombian Caribbean that is strongly influenced by changing environmental conditions due to a rainy and dry season. So far, the spatial and temporal distribution of P. volitans in the bays of TNNP is unknown. Therefore, this study assessed the abundance and body lengths of P. volitans during monthly surveys throughout the year 2012 in four bays (thereof two bays where lionfish removals were undertaken) of TNNP at 10 m water depth in coral reefs using transect tools. Findings revealed lionfish abundances of 2.9 ± 0.9 individuals ha(-1) with lengths of 20-25 cm for TNNP, hinting to an established, mostly adult local population. Actual TNNP lionfish abundances are thereby very similar to those at Indo-Pacific reef locations where the invasive lionfish formerly originated from. Significant spatial differences for lionfish abundances and body lengths between different bays in TNNP suggest habitat preferences of P. volitans depending on age. Lionfish abundances were highly variable over time, but without significant differences between seasons. Removals could not reduce lionfish abundances significantly during the period of study. This study therefore recommends improved management actions in order to control the already established invasive lionfish population in TNNP.

Prey-capture efficiency between juveniles and adults, feeding habitat and abundance of Wattled Jacana foragers in northern Pantanal, Mato Grosso state, Brazil / Eficiência de captura de presas entre jovens e adultos, habitat de alimentação e abundância de Jaçanãs forrageadores no Pantanal Norte, Mato Grosso, Brasil

The choice of foraging strategies implies an attempt at gaining energy by predators. Supposedly, the difference in employing the "sit and wait" or "active foraging" behavior lays in hunter skills, experience and the kind of prey consumed. With the hypothesis that "active foraging" demands no learning, in this study we compared the prey capture efficiency among Wattled Jacana juveniles and adults, and also present descriptive information about feeding habitat and the abundance variation of foragers throughout the day in the northern Pantanal. Prey capture efficiency did not differ significantly among juveniles and adults, corroborating our initial hypothesis that "active foraging" is an instinctive behavior and demands no experience to be effective. However, future work is necessary to compare the energetic quality of consumed items by juveniles and adults, searching for differences explained by adults' experience. Foraging individuals were found at an average distance of 14 m ranging from 2 to 42 m) from the margin of the sampled swamps, however 64% of the foragers were found closer to the margins. The average depth of foraging sites was 17 cm, ranging from 5 to 40 cm, although no preference for specific classes of depth was found (p > 0,05). Despite the accepted general pattern of birds being more active in the early morning, the largest number of individuals foraging was observed between 11:00 and 12:00 AM, but no significant difference was found in the abundance of foraging individuals among different periods of the day. Factors, which were not analyzed, such as food availability and presence of competitors and predators need to be studied to reveal the main factors of the spatial and temporal distribution of the Wattled Jacana.

A escolha de uma estratégia de forrageamento implica em uma tentativa de maximizar o ganho energético por predadores. Supostamente, a diferença em empregar o comportamento "senta e espera" ou o "forrageamento ativo" jaz sobre a habilidade de caça, a experiência e o tipo de presa consumida. A partir da hipótese de que o "forrageamento ativo" não demanda aprendizado, neste trabalho é comparada a eficiência de captura de presas entre jovens e adultos de Jaçanãs forrageadores, além de serem apresentadas informações descritivas sobre o habitat de alimentação e a variação na abundância de forrageadores ao longo do dia no Pantanal Norte. Os itens consumidos foram contabilizados para estimativas da eficiência de captura de presas, a qual não diferiu significativamente entre as classes etárias analisadas; corroborou-se, dessa forma, a hipótese inicial de que o "forrageamento ativo" é um comportamento instintivo e não demanda experiência para ter eficiência. No entanto, ainda é necessária pesquisa mais detalhada, comparando-se qualitativamente a dieta de jovens e adultos, com a intenção de testar se a experiência de adultos implica no consumo de presas com mais energia disponível. Os indivíduos forragearam, em média, a 14 m (amplitude de 2 a 42 m) de distância da margem dos brejos e lagoas amostradas; porém, 64% dos indivíduos avistados forrageavam em distâncias mais próximas da margem. A profundidade média dos locais de forrageio foi de 17 cm, com amplitude variando de 5 a 40 cm, não havendo preferência dos forrageadores por classes de profundidade específicas (p > 0,05). Apesar do padrão esperado para aves, segundo o qual a maior atividade ocorre nos momentos iniciais da manhã, o maior número de indivíduos forrageando foi observado entre 11:00 e 12:00 horas; porém, não houve diferença significativa na abundância de indivíduos forrageadores entre diferentes períodos do dia. Outros fatores, não analisados, tais como a disponibilidade alimentar e a presença de competidores e predadores, precisam ser estudados para se revelarem os principais determinantes da distribuição espacial e temporal dos Jaçanãs no Pantanal.

Distribución esaacial y temporal de náyades de donatos en los humedales la vacca y santa maría del lago, bogotá, Colombia / Spatial and Temporal Distribution of Dragonflies Naiads in Wetlands La Vaca and Santa Maria del Lago, Bogotá, Colombia

Se evaluaron la variación espacial y temporal de las comunidades de náyades de odonatos y su asociación al estado de rehabilitación de hábitat en los humedales La Vaca y Santa María del Lago. Mediante técnicas estandarizadas de recolección de macroinvertebrados, se realizaron cuatro muestreos en cada humedal a lo largo de un año en puntos a la entrada y salida y en el espejo de agua de los humedales. Se encontró un gradiente en la distribución de la abundancia de las náyades en ambos humedales, según el cual la comunidad presenta mayor número de ejemplares en los puntos de muestreos que se ubican espacialmente a mayores distancias de los sitios de vertimientos. Al comparar la composición entre los humedales La Vaca y Santa María del Lago mediante la evaluación de la diversidad beta, se encontró heterogeneidad de las comunidades de ambos ecosistemas. El gradiente en la distribución de la abundancia de las náyades observado en ambos humedales se ajusta a una respuesta de las especies en términos de tolerancia a las variables ambientales.

We evaluated the spatial and temporal variation in communities of dragonfly's naiads and their association to the habitat rehabilitation status in LaVaca and Santa María del Lagowetlands. Four samplings were carried out in several sites of each during a year. Macroinvertebrates were collected at the entryande exit flow, and in open waters of the wetlands using standard techniques. We found a gradient in the distribution of the abundance of nymphs in both wetlands, where naiads community had the highest number of individuals in the places located farther from the dumping sites. Comparing the community s composition between wetlands La Vaca and Santa María del Lago through the beta diversity, heterogeneity was found in both ecosystems. The gradient in the distribution of the abundance of naiads observed in both wetlands fits with to a response of the species in terms of tolerance to the environmental variables.

Estructura de la comunidad de macroinvertebrados del arroyo Achiras (Córdoba, Argentina): análisis previo a la construcción de una presa

La regulación de ríos y arroyos mediante diques modifica parámetros que influyen directamente sobre la biota. En la cuenca endorreica Achiras-del Gato ha finalizado recientemente la construcción de una presa de mediana envergadura que alterará las características limnológicas del sistema y la estructura de las comunidades bentónicas. Este estudio aporta los primeros registros del macrobentos de este sistema lótico y analiza la variación espacio-temporal de la estructura de la comunidad en tramos pedemontanos del arroyo Achiras. Durante un año, antes de la construcción de la presa, se colectaron muestras de zoobentos y se registraron variables abióticas en correderas y rabiones de dos sitios del arroyo, uno situado río arriba del área del dique y otro aguas abajo de la misma. Para cada sitio, hábitat y estación del año se determinó abundancia, frecuencia, riqueza taxonómica, Índice de Shannon y equidad, y se analizaron mediante ANOVA de una y tres vías. Los atributos de las comunidades de referencia se complementaron con la determinación de taxa exclusivos e indicadores y detectores ecológicos. En el primer sitio se registraron 73 taxa, Simulium fue más abundante y Leptohyphes eximius Eaton, 1882, más frecuente. En el segundo se hallaron 75 taxa, Caenis fue más abundante y Cricotopus sp. 3 más frecuente. La abundancia y la riqueza fueron significativamente mayores en primavera, y la diversidad en rabiones de invierno. Se determinó que los atributos de la comunidad estuvieron afectados por la época de muestreo. El arroyo Achiras posee un régimen hídrico freático-pluvial, con caudales bajos en invierno y altos en verano, por lo que se esperan cambios en la biota nativa y la integridad del sistema en respuesta a la reducción de la variabilidad hidráulica cuando el funcionamiento de la presa altere el caudal natural.

Regulation of rivers and streams modifies parameters that directly influence on the biota. In Achiras-del Gato endorheic basin has completed the construction of a midsize dam that will alter the limnological characteristics of the system and the structure of benthic communities. This study provides the first taxonomic records of macrobenthos of this lotic system and analyzes the spatial and temporal variations of the community structure in the foothills stretches of Achiras stream. Zoobenthos samples were collected and abiotic variables were recorded in runs and riffles, during a year, in two sites located upstream and downstream of the dam area, prior to the dam was built. For each site, habitat and season we determined the abundance, frequency, taxonomic richness, Shannon and evenness, and the data were analyzed using one-way and three-way ANOVA. Attributes of the reference communities were complemented by the determination of ecological indicators and detectors, and exclusive taxa. In the first site 73 taxa were recorded, Simulium was the most abundant and Leptohyphes eximius Eaton, 1882, was the most frequent. In the second site we found 75 taxa, Caenis was the most abundant and Cricotopus sp. 3, was the most frequent. In this study composition and distribution of the biota and indicators taxa are discussed. We determined that the community attributes were affected by the hydrological periods in wich the samples were taken. Achiras stream has a phreatic-pluvial hydrological regime with low flows in winter and high flows in summer. Therefore, we expect changes in native biota and in system integrity in response to hydraulic variability reduction when Achiras dam start functioning and alters the natural flow.

Estructura de la comunidad de macroinvertebrados del arroyo Achiras (Córdoba, Argentina): análisis previo a la construcción de una presa

La regulación de ríos y arroyos mediante diques modifica parámetros que influyen directamente sobre la biota. En la cuenca endorreica Achiras-del Gato ha finalizado recientemente la construcción de una presa de mediana envergadura que alterará las características limnológicas del sistema y la estructura de las comunidades bentónicas. Este estudio aporta los primeros registros del macrobentos de este sistema lótico y analiza la variación espacio-temporal de la estructura de la comunidad en tramos pedemontanos del arroyo Achiras. Durante un año, antes de la construcción de la presa, se colectaron muestras de zoobentos y se registraron variables abióticas en correderas y rabiones de dos sitios del arroyo, uno situado río arriba del área del dique y otro aguas abajo de la misma. Para cada sitio, hábitat y estación del año se determinó abundancia, frecuencia, riqueza taxonómica, Índice de Shannon y equidad, y se analizaron mediante ANOVA de una y tres vías. Los atributos de las comunidades de referencia se complementaron con la determinación de taxa exclusivos e indicadores y detectores ecológicos. En el primer sitio se registraron 73 taxa, Simulium fue más abundante y Leptohyphes eximius Eaton, 1882, más frecuente. En el segundo se hallaron 75 taxa, Caenis fue más abundante y Cricotopus sp. 3 más frecuente. La abundancia y la riqueza fueron significativamente mayores en primavera, y la diversidad en rabiones de invierno. Se determinó que los atributos de la comunidad estuvieron afectados por la época de muestreo. El arroyo Achiras posee un régimen hídrico freático-pluvial, con caudales bajos en invierno y altos en verano, por lo que se esperan cambios en la biota nativa y la integridad del sistema en respuesta a la reducción de la variabilidad hidráulica cuando el funcionamiento de la presa altere el caudal natural.

Regulation of rivers and streams modifies parameters that directly influence on the biota. In Achiras-del Gato endorheic basin has completed the construction of a midsize dam that will alter the limnological characteristics of the system and the structure of benthic communities. This study provides the first taxonomic records of macrobenthos of this lotic system and analyzes the spatial and temporal variations of the community structure in the foothills stretches of Achiras stream. Zoobenthos samples were collected and abiotic variables were recorded in runs and riffles, during a year, in two sites located upstream and downstream of the dam area, prior to the dam was built. For each site, habitat and season we determined the abundance, frequency, taxonomic richness, Shannon and evenness, and the data were analyzed using one-way and three-way ANOVA. Attributes of the reference communities were complemented by the determination of ecological indicators and detectors, and exclusive taxa. In the first site 73 taxa were recorded, Simulium was the most abundant and Leptohyphes eximius Eaton, 1882, was the most frequent. In the second site we found 75 taxa, Caenis was the most abundant and Cricotopus sp. 3, was the most frequent. In this study composition and distribution of the biota and indicators taxa are discussed. We determined that the community attributes were affected by the hydrological periods in wich the samples were taken. Achiras stream has a phreatic-pluvial hydrological regime with low flows in winter and high flows in summer. Therefore, we expect changes in native biota and in system integrity in response to hydraulic variability reduction when Achiras dam start functioning and alters the natural flow.

Prey-capture efficiency between juveniles and adults, feeding habitat and abundance of Wattled Jacana foragers in northern Pantanal, Mato Grosso state, Brazil

The choice of foraging strategies implies an attempt at gaining energy by predators. Supposedly, the difference in employing the "sit and wait" or "active foraging" behavior lays in hunter skills, experience and the kind of prey consumed. With the hypothesis that "active foraging" demands no learning, in this study we compared the prey capture efficiency among Wattled Jacana juveniles and adults, and also present descriptive information about feeding habitat and the abundance variation of foragers throughout the day in the northern Pantanal. Prey capture efficiency did not differ significantly among juveniles and adults, corroborating our initial hypothesis that "active foraging" is an instinctive behavior and demands no experience to be effective. However, future work is necessary to compare the energetic quality of consumed items by juveniles and adults, searching for differences explained by adults' experience. Foraging individuals were found at an average distance of 14 m ranging from 2 to 42 m) from the margin of the sampled swamps, however 64% of the foragers were found closer to the margins. The average depth of foraging sites was 17 cm, ranging from 5 to 40 cm, although no preference for specific classes of depth was found (p > 0,05). Despite the accepted general pattern of birds being more active in the early morning, the largest number of individuals foraging was observed between 11:00 and 12:00 AM, but no significant difference was found in the abundance of foraging individuals among different periods of the day. Factors, which were not analyzed, such as food availability and presence of competitors and predators need to be studied to reveal the main factors of the spatial and temporal distribution of the Wattled Jacana.

A escolha de uma estratégia de forrageamento implica em uma tentativa de maximizar o ganho energético por predadores. Supostamente, a diferença em empregar o comportamento "senta e espera" ou o "forrageamento ativo" jaz sobre a habilidade de caça, a experiência e o tipo de presa consumida. A partir da hipótese de que o "forrageamento ativo" não demanda aprendizado, neste trabalho é comparada a eficiência de captura de presas entre jovens e adultos de Jaçanãs forrageadores, além de serem apresentadas informações descritivas sobre o habitat de alimentação e a variação na abundância de forrageadores ao longo do dia no Pantanal Norte. Os itens consumidos foram contabilizados para estimativas da eficiência de captura de presas, a qual não diferiu significativamente entre as classes etárias analisadas; corroborou-se, dessa forma, a hipótese inicial de que o "forrageamento ativo" é um comportamento instintivo e não demanda experiência para ter eficiência. No entanto, ainda é necessária pesquisa mais detalhada, comparando-se qualitativamente a dieta de jovens e adultos, com a intenção de testar se a experiência de adultos implica no consumo de presas com mais energia disponível. Os indivíduos forragearam, em média, a 14 m (amplitude de 2 a 42 m) de distância da margem dos brejos e lagoas amostradas; porém, 64% dos indivíduos avistados forrageavam em distâncias mais próximas da margem. A profundidade média dos locais de forrageio foi de 17 cm, com amplitude variando de 5 a 40 cm, não havendo preferência dos forrageadores por classes de profundidade específicas (p > 0,05). Apesar do padrão esperado para aves, segundo o qual a maior atividade ocorre nos momentos iniciais da manhã, o maior número de indivíduos forrageando foi observado entre 11:00 e 12:00 horas; porém, não houve diferença significativa na abundância de indivíduos forrageadores entre diferentes períodos do dia. Outros fatores, não analisados, tais como a disponibilidade alimentar e a presença de competidores e predadores, precisam ser estudados para se revelarem os principais determinantes da distribuição espacial e temporal dos Jaçanãs no Pantanal.

Taxocenose de bagres marinhos (Siluriformes, Ariidae) da região estuarina de São Vicente, SP, Brasil / Taxocenose of marine catfish (Siluriformes, Ariidae) in the complex bay-estuary of São Vicente, SP, Brazil

O objetivo do trabalho foi analisar a taxocenose de bagres marinhos do complexo baía-estuário de São Vicente, SP. As coletas foram mensais, no período de setembro de 2000 a agosto de 2002, em quatro regiões do estuário. Foram capturados 3.985 exemplares, pertencentes a cinco gêneros e seis espécies, totalizando 47.807 g. A espécie Cathorops spixii apresentou a maior abundância numérica com 1.569 indivíduos amostrados. No transecto I (próximo da região costeira) foi registrada a maior riqueza e no transecto IV (estuário acima) a maior abundância com 2.602 exemplares e peso de 26.236 g. Em março de 2002 registrou-se a maior abundância com 687 indivíduos e o maior peso ocorreu em fevereiro de 2002 (8.816 g). A salinidade da água de fundo, ao longo do período de estudo, variou entre 14 e 36 e a temperatura da água variou entre 19 e 30 ºC. Na região amostrada foram capturados exemplares jovens e adultos, ocorrendo um predomínio de jovens, o que demonstra que esta área apresenta condições favoráveis para crescimento.

The purpose of this study was to analyze the taxocenose of marine catfish in the complex bay-estuary of Sao Vicente, Brazil. The sampling was done monthly from September/2000 to August/2002, in four places of the estuary. Were caught 3.985 individuals belonging for 5 genus and 6 species, totalizing 47.807 g. The specie Cathorops spixii showed the biggest plentiful with 1.569 individuals sampled. In the transect I (close to the coastal region), it was registered the biggest richness (6 species) and in the transect IV (upper estuary) the biggest number of individuals (n = 2.602) e weight of 26.236 g. In March/2002 were registered the biggest occurrence with 687 individuals and biggest weight in February/2002 (8.816 g). The bottom water salinity, in the time of study, changed between 14 and 36, and the water temperature varied between 19 and 30 ºC. In the sample place juveniles and adults' individuals were caught, a mostly juvenile which demonstrates that of this place shows favorable conditions for growth.

Diversidad y abundancia ictiofaunística del río Grande de Térraba, sur de Costa Rica

The diversity, abundance and distributional pattern of freshwater fish communities in the Térraba River, south Costa Rica, were investigated from the early dry season of 2004 to early rain season of 2005. There have been no preview studies on the freshwater fish distribution in Térraba. Therefore, the aims of this study were to determine fish species richness, abundance and distribution there. Fish sampling was done using a combination of gears such as gill net, fine mesh net and visual observation. Thirty three species, 26 genera and 14 families were collected in four sampling sites along the river. The number and biomass captured during the entire study was 984 individuals and 147 410.9 g respectively. Most of them are carnivorous species (48%), 33.3% are omnivorous and 12% detritivorous, and only two species are herbivorous. The most important species in relative abundance (56.5%) and biomass (53.7%) in the study area was the machaca (Brycon behreae). It should be clear that although the list of fish species that occur in Térraba River is reasonably complete, knowledge of their ichthyogeographic history patterns is superficial. The main community component was secondary freshwater species; with 17 invading brackish water species and one introduced species (tilapia O. niloticus). Nine species are reported for the first time in this river. The diversity index H` varied from 2.32 (El Brujo) to 1.67 (Coto), a similar pattern was also showed for the other indexes. Most of our results were similar to those of previous studies on freshwater fish distribution elsewhere, however no significant correlation between species distribution and environmental variables was found, and we hypothesized that the depth and water velocity and geomorphological are major environmental variables that influence the fish distribution. Our findings are opposed to the tendency, for species composition, to increase from upstream to the mouth of the river, which is probably due to two major human activities (discharge of waste of pineapple fields and sediments in the main channel). These activities could constitute in the future a real threat for the fish population and other aquatic organisms. Growth rates, competition, predation pressures, community organization, biotic versus physical factors in relation to distribution, and many other aspects of fish biology remain to be studied. Future surveys will involve more quantitative surveys in different seasons and over time to monitor the long-term variation in the diversity and abundance of freshwater fish species in Térraba. Rev. Biol. Trop. 56 (3): 1429-1447. Epub 2008 September 30.

Desde el inicio de la estación seca del 2004 hasta la estación lluviosa de 2005, se llevó a cabo una investigación, con el objetivo de determinar la diversidad, abundancia y patrones de distribución de las comunidades de peces de agua dulce del río Grande de Térraba. El muestreo de peces se llevó a cabo utilizando una combinación de artes de pesca, entre ellas las redes agalleras, redes finas y observaciones visuales. Fueron recolectadas 33 especies, 14 familias y 26 géneros en las cuatro estaciones. Se capturaron 984 ejemplares para una biomasa de 147 410.9 g. La mayoría de las especies son carnívoras (48%), 33.3% son omnívoras y 12% detritívoras y sólo dos especies son herbívoras. La especie con mayor abundancia relativa (56.5%) y biomasa (53.7) fue la machaca (Brycon behreae). Aunque la lista de especies de peces en el río Térraba parece razonablemente completa, el conocimiento sobre los patrones ictiogegráficos es superficial. El principal componente comunitario son los peces de agua dulce secundarios con 17 especies estuarinas y una especie introducida (tilapia O. niloticus). Nueve especies son registradas por primera vez. El índice de diversidad H´ varió de 2.32 (El Brujo) a 1.67 (Coto), un patrón similar se encontró para los otros índices aplicados. Muchos de nuestros resultados fueron similares a los de previos estudios sobre distribución de peces de agua dulce en otras zonas, sin embargo no se encontró correlación significativa entre la distribución de especies y las variables ambientales. Se hipotetiza que la profundidad, velocidad del agua y atributos geomorfológicos son las variables físicas que influencian la distribución de peces. Los resultados de este estudio difieren de la tendencia de que la riqueza de especies se incrementa desde la parte alta hacia la boca del río, esta condición se atribuye a dos actividades humanas (descarga al canal principal de desechos de los cultivos de piña y sedimentos contaminados). Estas actividades podrían ser, en el futuro, una amenaza real sobre los peces y otros organismos acuáticos. Se deben estudiar otros aspectos de la historia natural de los peces de la zona, tales como crecimiento, competencia, depredación, organización comunitaria y los factores físicos y/o bióticos relacionados con la distribución ictiofaunística.

Taxocenose de anuros de uma mata semidecídua do interior do Estado de São Paulo e comparações com outras taxocenoses do estado, sudeste do Brasil / Anurans of a semidecidual forest in the interior of the São Paulo state and comparisons with other assemblages of the State, Southeastern Brazil

O presente estudo foi realizado em um fragmento de floresta semidecídua, Mata São José (MSJ), e em áreas adjacentes ao fragmento localizado no município de Rio Claro, Estado de São Paulo, Brasil. Informações sobre a composição e distribuição espacial e temporal de espécies de anuros foram coletadas entre agosto de 2002 e julho de 2003. Foram registradas 24 espécies, sendo que a maioria foi observada em atividade de vocalização e reprodução nas áreas abertas adjacentes ao fragmento. Apenas três espécies, Hypsiboas lundii, H. prasinus e Proceratophrys boiei foram observadas utilizando ambientes no interior do fragmento para a reprodução e apenas H. prasinus foi registrada também em ambientes adjacentes ao fragmento. A maioria das espécies foi registrada durante a estação chuvosa da região e os ambientes temporários foram os mais utilizados para reprodução. A composição de espécies da MSJ foi comparada com a de outras 10 localidades com as seguintes fisionomias vegetais e status de conservação: floresta tropical preservada, ecótono de floresta ombrófila e floresta estacional semidecídua pouco preservada, Cerrado preservado e áreas antropizadas principalmente pela implantação de agricultura e pastagem. A composição de espécies da MSJ e da área de floresta estacional semidecídua foram mais similares entre si e com áreas perturbadas e área de Cerrado que quando comparadas a composição de espécies da área de floresta tropical preservada. Não houve correlação entre as distâncias e a similaridade na composição da anurofauna das localidades comparadas. Proceratophrys boiei e H. lundii aparentemente são as espécies mais afetadas pelo processo de fragmentação ambiental no Estado de São Paulo, provavelmente devido a sua ecologia e dependência de ambientes mais florestados.

The present study was conducted in a remnant of semi-deciduous forest, Mata São José (MSJ), and in its adjacent areas in the municipality of Rio Claro, state of São Paulo, Brazil. Information about anuran species richness and their spatial and temporal distribution were collected from August 2002 to July 2003. Most of the 24 registered species called and breed in open areas around the remnant. Only three species, Hypsiboas lundii, H. prasinus, and Proceratophrys boiei, used environments inside the fragment as reproductive sites and only H. prasinus used also environments around the remnant. The majority of the species were found during the rainy season and temporary environments were the most used for reproduction. The species composition of MSJ was compared with 10 other localities with the following vegetation composition: a preserved tropical rain forest, ecotone of tropical rain forest and semi-deciduous altered forest, preserved Cerrado, and disturbed areas (used as agriculture and pasture for cattle). The anuran composition of the MSJ and that from other semi-deciduous forest were more similar to the anuran composition of more perturbed areas and to the anuran composition of Cerrado then to the anuran composition of the rain forest habitats. There was no significant correlation between the distance of the areas and the similarity ratio of them. Proceratophrys boiei and H. lundii appear to be the species more affected by habitat fragmentation in the state of São Paulo due to their reproductive ecology and dependence of forested habitats.

Spatial and temporal distribution in density and biomass of two Pseudodiaptomus species (Copepoda: Calanoida) in the Caeté river estuary (Amazon region - North of Brazil)

Spatial and temporal density and biomass distribution of the planktonic copepods Pseudodiaptomus richardi and P. acutus along a salinity gradient were investigated in the Caeté River Estuary (North-Brazil) in June and December, 1998 (dry season) and in February and May, 1999 (rainy season). Copepod biomass was estimated using regression parameters based on the relation of dry weight and body length (prosome) of adult organisms. The Caeté River Estuary was characterized by high spatial and temporal variations in salinity (0.8-37.2‰). Exponential length-weight relationships were observed for both Pseudodiaptomus species. Density and biomass values oscillated between 0.28-46.18 ind. m-3 and 0.0022-0.3507 mg DW. m-3 for P. richardi; and between 0.01-17.02 ind. m-3 and 0.0005-0.7181 mg DW. m-3 for P. acutus. The results showed that the contribution of P. richardi for the secondary production in the Caeté River Estuary is more important in the limnetic zone than in other zones where euhaline-polyhaline regimes were predominant. However, it was not possible to observe a clear pattern of spatial and temporal distribution for P. acutus.

A distribuição espacial e temporal da densidade e biomassa dos copépodos planctônicos Pseudodiaptomus richardi e P. acutus, ao longo de um gradiente de salinidade, foi estudada no Estuário do Rio Caeté (Norte do Brasil) durante os meses de junho e dezembro de 1998 (estação seca) e fevereiro e maio de 1999 (estação chuvosa). A biomassa dos copépodos foi estimada a partir de parâmetros da regressão baseada na relação entre o peso seco e o comprimento do corpo (prossoma) de organismos adultos. O Estuário do Rio Caeté caracterizou-se por uma grande variação espacial e sazonal na salinidade (0,8-37,2‰). A relação peso-comprimento para ambas as espécies de Pseudodiaptomus foi do tipo exponencial. Os valores de densidade e biomassa oscilaram entre 0,28-46,18 ind. m-3 e 0,0022-0,3507 mg DW. m-3 para P. richardi; e entre 0,01-17,02 ind. m-3 e 0,0005-0,7181 mg DW. m-3 para P. acutus. Os resultados revelaram que a contribuição de P. richardi para a produção secundária no Estuário do Rio Caeté é mais importante na zona liminética que em outras zonas onde foram dominantes os regimes eurihalino-polihalino. Contudo, para P. acutus não foi possível observar de forma clara um padrão de distribuição espacial e temporal para a área estudada.

Spatial and temporal distribution in density and biomass of two Pseudodiaptomus species (Copepoda: Calanoida) in the Caeté river estuary (Amazon region - North of Brazil)

Spatial and temporal density and biomass distribution of the planktonic copepods Pseudodiaptomus richardi and P. acutus along a salinity gradient were investigated in the Caeté River Estuary (North-Brazil) in June and December, 1998 (dry season) and in February and May, 1999 (rainy season). Copepod biomass was estimated using regression parameters based on the relation of dry weight and body length (prosome) of adult organisms. The Caeté River Estuary was characterized by high spatial and temporal variations in salinity (0.8-37.2‰). Exponential length-weight relationships were observed for both Pseudodiaptomus species. Density and biomass values oscillated between 0.28-46.18 ind. m-3 and 0.0022-0.3507 mg DW. m-3 for P. richardi; and between 0.01-17.02 ind. m-3 and 0.0005-0.7181 mg DW. m-3 for P. acutus. The results showed that the contribution of P. richardi for the secondary production in the Caeté River Estuary is more important in the limnetic zone than in other zones where euhaline-polyhaline regimes were predominant. However, it was not possible to observe a clear pattern of spatial and temporal distribution for P. acutus.

A distribuição espacial e temporal da densidade e biomassa dos copépodos planctônicos Pseudodiaptomus richardi e P. acutus, ao longo de um gradiente de salinidade, foi estudada no Estuário do Rio Caeté (Norte do Brasil) durante os meses de junho e dezembro de 1998 (estação seca) e fevereiro e maio de 1999 (estação chuvosa). A biomassa dos copépodos foi estimada a partir de parâmetros da regressão baseada na relação entre o peso seco e o comprimento do corpo (prossoma) de organismos adultos. O Estuário do Rio Caeté caracterizou-se por uma grande variação espacial e sazonal na salinidade (0,8-37,2‰). A relação peso-comprimento para ambas as espécies de Pseudodiaptomus foi do tipo exponencial. Os valores de densidade e biomassa oscilaram entre 0,28-46,18 ind. m-3 e 0,0022-0,3507 mg DW. m-3 para P. richardi; e entre 0,01-17,02 ind. m-3 e 0,0005-0,7181 mg DW. m-3 para P. acutus. Os resultados revelaram que a contribuição de P. richardi para a produção secundária no Estuário do Rio Caeté é mais importante na zona liminética que em outras zonas onde foram dominantes os regimes eurihalino-polihalino. Contudo, para P. acutus não foi possível observar de forma clara um padrão de distribuição espacial e temporal para a área estudada.