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The deep Peru Basin is characterised by a unique abyssal scavenging community featuring large numbers of hermit crabs (Probeebei mirabilis, Decapoda, Crustacea). These are atypical hermit crabs, not carrying a shell, but on some occasions carrying an anemone (Actiniaria). The reason why some hermit crabs carry or not carry anemones is thought to be indicative of a changed environment, outweighing the cost/benefit of their relationship. Here we present the temporal variation of abundances of P. mirabilis with and without anemones, spanning more than two decades, following a benthic impact experiment. An overall decrease in hermit crab densities was observed, most noticeable and significant after 26 years and characterised by a loss of Actiniaria on the Probeebei mirabilis' pleon. Whether this is a delayed response to the benthic impact experiment carried out 26 years' prior or a natural variation in the population remains to be corroborated by an extension of the time-series. Attention is drawn to the limitations of our knowledge over time and space of the abyssal community dynamics and the urgent necessity to fill in these gaps prior to any type of deep-sea exploitation.

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Naturally fragmented landscapes are adequate systems for evaluating patterns and mechanisms that determine species distribution without confounding effects of anthropogenic fragmentation and habitat loss. We aimed to evaluate an ant metacommunity's spatiotemporal patterns in montane forest islands amid a grassland-dominated matrix. We assessed these patterns by deconstructing the ant metacommunity into forest-dependent and habitat generalist species. We sampled twice a year (summer and winter) over 2 years (2014 and 2015), using soil and arboreal pitfall traps, in fourteen forest islands (varying in size, shape, and connectivity) in the Espinhaço Range Biosphere Reserve, Brazil. We evaluated the relationship between ant species richness, composition (ß-diversity), and predictor variables of forest island structure (canopy cover and understory density) and landscape structure (forest amount, number of forest islands, and shape). We sampled 99 ant species, 66.7% of which were classified as forest-dependent and 33.3% as habitat generalist species. We found that ant ß-diversity was higher in space than in time, and that species composition variation in time (temporal ß-diversity) differed between ant species groups. Both ant groups responded differently to forest island and landscape structure characteristics. Landscape structure seems to act as a spatial filter and the forest islands' local characteristics as an environmental filter, which jointly determine the local and regional diversity. We demonstrate the importance that forest archipelagos pose to ant metacommunity's structure and dynamics in montane tropical regions. Mountaintop conservation and management strategies must consider the forest island archipelago to maintain the biodiversity and the functioning of these systems.

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We detail the benthic compositon of the turbid-water coral reefs of Tobago in 2016 and examine the influence of mass coral bleaching and hydro-geomorphic setting (sheltereted vs. wave-exposed) on benthic community dynamics against the 2007 baseline. In the current assessment mean hard coral cover was 14.83% ± 0.85, which ranged from 2% to 37% with few sites exceeding 20%. Mean macroalgal cover was low (6.04% ± 0.61) with most sites experiencing less than 8% macroalgal cover. Differences in benthic cover between sheltered and wave-exposed settings were mainly driven by contrasts in proportions of sponge, macroalgae and Orbicella faveolata corals. Linear mixed-effects modelling suggests stability in hard coral cover and decline in macroalgal cover across sites against the 2007 baseline. Significant spatio-temporal interactions were observed for soft coral and CTB (crustose coralline algae, turf algae and bare substrate). Overall, hard coral cover appears to have declined at some sites and macroalgal cover to have increased at other, but there is no evidence of widespread regime shift. While the hydro-geomorphic setting had a significant but weak effect (R > 0.3) on observed spatial and temporal patterns, our findings suggest that sheltered settings were less predisposed to macroalgal overgrowth compared to wave-exposed areas. In the era of climate change, targeted management should focus on strategies that mitigate macroalgal overgrowth, promote hard coral stability (or resilience) while preventing further loss.

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Second-generation biofuel production is in high demand, but lignocellulosic biomass' complexity impairs its use due to the vast diversity of enzymes necessary to execute the complete saccharification. In nature, lignocellulose can be rapidly deconstructed due to the division of biochemical labor effectuated in bacterial communities. Here, we analyzed the lignocellulolytic potential of a bacterial consortium obtained from soil and dry straw leftover from a sugarcane milling plant. This consortium was cultivated for 20 weeks in aerobic conditions using sugarcane bagasse as a sole carbon source. Scanning electron microscopy and chemical analyses registered modification of the sugarcane fiber's appearance and biochemical composition, indicating that this consortium can deconstruct cellulose and hemicellulose but no lignin. A total of 52 metagenome-assembled genomes from eight bacterial classes (Actinobacteria, Alphaproteobacteria, Bacilli, Bacteroidia, Cytophagia, Gammaproteobacteria, Oligoflexia, and Thermoleophilia) were recovered from the consortium, in which ~46% of species showed no relevant modification in their abundance during the 20 weeks of cultivation, suggesting a mostly stable consortium. Their CAZymes repertoire indicated that many of the most abundant species are known to deconstruct lignin (e.g., Chryseobacterium) and carry sequences related to hemicellulose and cellulose deconstruction (e.g., Chitinophaga, Niastella, Niabella, and Siphonobacter). Taken together, our results unraveled the bacterial diversity, enzymatic potential, and effectiveness of this lignocellulose-decomposing bacterial consortium.

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Temporal scale in animal communities is often associated with seasonality, despite the large variation in species activity during a diel cycle. A gap thus remains in understanding the dynamics of short-term activity in animal communities. Here we assessed calling activity of tropical anurans and addressed how species composition varied during night activity in assemblages along gradients of local and landscape environmental heterogeneity. We investigated 39 anuran assemblages in the Pantanal wetlands (Brazil) with passive acoustic monitoring during the peak of one breeding season, and first determined changes in species composition between night periods (early, mid and late) using two temporal resolutions (1- and 3-hr intervals). Then, we addressed the role of habitat structure (local and landscape heterogeneity variables from field-based and remote sensing metrics) and ecological context (species richness and phylogenetic relatedness) in determining changes in species composition (a) between night periods and (b) across days. Nocturnal calling activity of anuran assemblages varied more within the 1-hr resolution than the 3-hr resolution. Differences in species composition between early- and late-night periods were related to local habitat structure and phylogenetic relatedness, while a low variation in compositional changes across days was associated with low-heterogeneous landscapes. None of these relationships were observed using the coarser temporal resolution (3 hr). Our findings on the variation of calling activity in tropical anuran assemblages suggest potential trade-offs mediated by fine-temporal partitioning. Local and landscape heterogeneity may provide conditions for spatial partitioning, while the relatedness among co-signalling species provides cues on the ecological overlap of species with similar requirements. These relationships suggest a role of niche dimensional complementarity on the structuring of these anuran assemblages over fine-temporal scales. We argue that fine-temporal differences between species in breeding activity can influence the outcome of species interaction and thus, addressing temporal scaling issues can improve our understanding of the dynamics of animal communities.

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The Cerrado has a wide diversity of fauna and flora, and the knowledge of its horizontal structure, in different time intervals allows the prediction of its structural and floristic characteristics. The aim of this study was to evaluate the changes in structure and composition of tree community in three fragments of Cerrado with low anthropization, in an interval of 11 years at Minas Gerais state. Rectangular plots of fixed size were sampled, measuring stem diameter and height of all living arboreal individuals with diameter at 1.30 meters above ground (DBH) ≥ 5 cm. The tree vegetation dynamics study of the areas was performed, as well as the floristic analysis and the diametric structure. Considering all fragments and years of measurement, the recruitment of trees surpassed its mortality. The basal area varied between 3.67 and 13.07 m².ha-1. The studied areas, considering all fragments and years of measurement, showed a Shannon diversity index (H') from 3.43 to 3.87 nat.ind-1 and Pielou equitability index (J') ranged an interval between 0.77 and 0.82. The similarity calculated by the Jaccard index (J), when performed per plot considering the three fragments, showed a value of 0.2653. Also, related to the development and growth of the study areas, it can be inferred that all fragments and their respective years of measurement had a J-inverse pattern. In conclusion, it can be inferred that the three fragments maintained a representative growth in number of individuals and basal area.

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The Cerrado has a wide diversity of fauna and flora, and the knowledge of its horizontal structure, in different time intervals allows the prediction of its structural and floristic characteristics. The aim of this study was to evaluate the changes in structure and composition of tree community in three fragments of Cerrado with low anthropization, in an interval of 11 years at Minas Gerais state. Rectangular plots of fixed size were sampled, measuring stem diameter and height of all living arboreal individuals with diameter at 1.30 meters above ground (DBH) ≥ 5 cm. The tree vegetation dynamics study of the areas was performed, as well as the floristic analysis and the diametric structure. Considering all fragments and years of measurement, the recruitment of trees surpassed its mortality. The basal area varied between 3.67 and 13.07 m².ha-1. The studied areas, considering all fragments and years of measurement, showed a Shannon diversity index (H') from 3.43 to 3.87 nat.ind-1 and Pielou equitability index (J') ranged an interval between 0.77 and 0.82. The similarity calculated by the Jaccard index (J), when performed per plot considering the three fragments, showed a value of 0.2653. Also, related to the development and growth of the study areas, it can be inferred that all fragments and their respective years of measurement had a J-inverse pattern. In conclusion, it can be inferred that the three fragments maintained a representative growth in number of individuals and basal area.(AU)

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Species composition and community structure in Neotropical forests have been severely affected by increases in climate change and disturbance. Among the most conspicuous changes is the proliferation of lianas. These increases have affected not only the carbon storage capacity of forests but also tree dynamics by reducing tree growth and increasing mortality. Despite the importance of lianas in Neotropical forests, most of the studies on lianas have focused on adult stages, ignoring dynamics at the seedlings stage. Here, we asked whether observed increases in liana abundance are associated with a demographic advantage that emerges early in liana ontogeny and with decreased precipitation and increased disturbance. To test this, we compared patterns of growth and survival between liana seedlings and tree seedlings using a long-term data set of seedling plots from a subtropical wet forest in Puerto Rico, USA. Then, we examined the effect of precipitation and land use history on these demographic variables. We found evidence for liana seedling survival advantage over trees, but no growth advantages. This survival advantage exhibited significant temporal variation linked with patterns of rainfall, as well as differences associated with land-use history in the study area. Furthermore, we found that neighborhood density has a negative effect on liana survival and growth. Our results indicate that liana proliferation is likely related to a survival advantage that emerges in early stages and is influenced by climatic conditions and past disturbance. Predicted climatic changes in rainfall patterns, including more frequent and severe droughts, together with increases in disturbance, could have a significant effect on seedling tropical communities by favoring lianas.

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Abiotic constraints and biotic interactions act simultaneously to shape communities. However, these community assembly mechanisms are often studied independently, which can limit understanding of how they interact to affect species dynamics and distributions. We develop a hierarchical Bayesian neighborhood modeling approach to quantify the simultaneous effects of topography and crowding by neighbors on the growth of 124,704 individual stems ≥1 cm DBH for 1,047 tropical tree species in a 25-ha mapped rainforest plot in Amazonian Ecuador. We build multi-level regression models to evaluate how four key functional traits (specific leaf area, maximum tree size, wood specific gravity and seed mass) mediate tree growth response to topography and neighborhood crowding. Tree growth is faster in valleys than on ridges and is reduced by neighborhood crowding. Topography and crowding interact to influence tree growth in ~10% of the species. Specific leaf area, maximum tree size and seed mass are associated with growth responses to topography, but not with responses to neighborhood crowding or with the interaction between topography and crowding. In sum, our study reveals that topography and neighborhood crowding each influence tree growth in tropical forests, but act largely independently in shaping species distributions. While traits were associated with species response to topography, their role in species response to neighborhood crowding was less clear, which suggests that trait effects on neighborhood dynamics may depend on the direction (negative/positive) and degree of symmetry of biotic interactions. Our study emphasizes the importance of simultaneously assessing the individual and interactive role of multiple mechanisms in shaping species dynamics in high diversity tropical systems.

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Seasonal upwelling at the northern Pacific coast of Costa Rica offers the opportunity to investigate the effects of pronounced changes in key water parameters on fine-scale dynamics of local coral reef communities. This study monitored benthic community composition at Matapalo reef (10.539°N, 85.766°W) by weekly observations of permanent benthic quadrats from April 2013 to April 2014. Monitoring was accompanied by surveys of herbivore abundance and biomass and measurements of water temperature and inorganic nutrient concentrations. Findings revealed that the reef-building corals Pocillopora spp. exhibited an exceptional rapid increase from 22 to 51% relative benthic cover. By contrast, turf algae cover decreased from 63 to 24%, resulting in a corresponding increase in crustose coralline algae cover. The macroalga Caulerpa sertularioides covered up to 15% of the reef in April 2013, disappeared after synchronized gamete release in May, and subsequently exhibited slow regrowth. Parallel monitoring of influencing factors suggest that C. sertularioides cover was mainly regulated by their reproductive cycle, while that of turf algae was likely controlled by high abundances of herbivores. Upwelling events in February and March 2014 decreased mean daily seawater temperatures by up to 7 °C and increased nutrient concentrations up to 5- (phosphate) and 16-fold (nitrate) compared to mean values during the rest of the year. Changes in benthic community composition did not appear to correspond to the strong environmental changes, but rather shifted from turf algae to hard coral dominance over the entire year of observation. The exceptional high dynamic over the annual observation period encourages further research on the adaptation potential of coral reefs to environmental variability.

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We evaluated how seasonality affects the frequency and intensity of fin-nipping, as well as the fish prey preferences of Serrasalmus maculatus Kner, 1858. The study took place in a small reservoir of the Ribeirão Claro River basin, state of São Paulo, southeastern Brazil. Fish were sampled monthly from July 2003 to June 2004, using gillnets. Sampling consisted of leaving 50 m of gillnets in the water for approximately 24 hours each month. No seasonal variation in the frequency and intensity of fin-nipping was observed. Among six prey species, piranhas displayed less damage in their fins, possibly due to intraspecific recognition. Under natural conditions, the caudal fins of Cyphocharax modestus (Fernández-Yépez, 1948) were the most intensively mutilated, which suggests multiple attacks on the same individual. The size of individuals in this species was positively correlated with the mutilated area of the fin, whereas no such correlation was observed for Astyanax altiparanae Garutti & Britski, 2000 and Acestrorhynchus lacustris (Lütken, 1875). The high number of mutilated fish under natural conditions strongly suggests that the relationship between S. maculatus and its prey is more akin to parasitism than to predation. If mutilated fins negatively affect the ability of prey to swim, the spread of S. maculatus might result in an unnatural impact on prey fish assemblages and population structure after damming.

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We evaluated how seasonality affects the frequency and intensity of fin-nipping, as well as the fish prey preferences of Serrasalmus maculatus Kner, 1858. The study took place in a small reservoir of the Ribeirão Claro River basin, state of São Paulo, southeastern Brazil. Fish were sampled monthly from July 2003 to June 2004, using gillnets. Sampling consisted of leaving 50 m of gillnets in the water for approximately 24 hours each month. No seasonal variation in the frequency and intensity of fin-nipping was observed. Among six prey species, piranhas displayed less damage in their fins, possibly due to intraspecific recognition. Under natural conditions, the caudal fins of Cyphocharax modestus (Fernández-Yépez, 1948) were the most intensively mutilated, which suggests multiple attacks on the same individual. The size of individuals in this species was positively correlated with the mutilated area of the fin, whereas no such correlation was observed for Astyanax altiparanae Garutti & Britski, 2000 and Acestrorhynchus lacustris (Lütken, 1875). The high number of mutilated fish under natural conditions strongly suggests that the relationship between S. maculatus and its prey is more akin to parasitism than to predation. If mutilated fins negatively affect the ability of prey to swim, the spread of S. maculatus might result in an unnatural impact on prey fish assemblages and population structure after damming.(AU)

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The Janzen-Connell hypothesis proposes that specialist natural enemies, such as herbivores and pathogens, maintain diversity in plant communities by reducing survival rates of conspecific seeds and seedlings located close to reproductive adults or in areas of high conspecific density. Variation in the strength of distance- and density-dependent effects is hypothesized to explain variation in plant species richness along climatic gradients, with effects predicted to be stronger in the tropics than the temperate zone and in wetter habitats compared to drier habitats.We conducted a comprehensive literature search to identify peer-reviewed experimental studies published in the 40+ years since the hypothesis was first proposed. Using data from these studies, we conducted a meta-analysis to assess the current weight of evidence for the distance and density predictions of the Janzen-Connell hypothesis.Overall, we found significant support for both the distance- and density-dependent predictions. For all studies combined, survival rates were significantly reduced near conspecifics compared to far from conspecifics, and in areas with high densities of conspecifics compared to areas with low conspecific densities. There was no indication that these results were due to publication bias.The strength of distance and density effects varied widely among studies. Contrary to expectations, this variation was unrelated to latitude, and there was no significant effect of study region. However, we did find a trend for stronger distance and density dependence in wetter sites compared to sites with lower annual precipitation. In addition, effects were significantly stronger at the seedling stage compared to the seed stage.Synthesis. Our study provides support for the idea that distance- and density-dependent mortality occurs in plant communities world-wide. Available evidence suggests that natural enemies are frequently the cause of such patterns, consistent with the Janzen-Connell hypothesis, but additional studies are needed to rule out other mechanisms (e.g. intraspecific competition). With the widespread existence of density and distance dependence clearly established, future research should focus on assessing the degree to which these effects permit species coexistence and contribute to the maintenance of diversity in plant communities.

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El propósito del estudio es establecer los conocimientos, la dinámica familiar y comunitaria de madres de hijos con discapacidad que sirvan de base para la instrumentación de programas de intervención. Participaron 42 madres con edades entre 19 y 49 años (M = 31.14) de un Centro de Rehabilitación Infantil perteneciente a la Secretaría de la Defensa Nacional en México. Se utilizó una guía de entrevista semi-estructurada para explorar los conocimientos, la dinámica familiar y comunitaria de las familias. Las madres reportaron que no recibieron preparación de cómo tratar a sus hijos; sin embargo, ellas consideran la importancia de adquirir conocimientos especializados para entender y tratar al menor. Las madres que no tienen los conocimientos necesarios sobre la discapacidad de su hijo no son capaces de entender ni aceptar la condición del niño, conllevando a la negación del problema, inconformidad, culpa y depresión. Se observó en el estudio que una adecuada preparación de la madre después del nacimiento de su hijo, acerca de la discapacidad, puede proveer una mejor interacción y funcionamiento de estas familias.

The purpose of this study is to enquire about the knowledge, as well as about the family and community dynamics of mothers of children with disabilities, as a basis to implement intervention programs. Participants were 42 mothers aged between 19 and 49 years (M= 31.14) who attended a Children's Rehabilitation Center belonging to the National Defense Secretariat in Mexico [SEDENA, for its Spanish acronym]. Semi-structured interviews were used to assess the mother's knowledge on the disability of the child and the family and community dynamics. Mothers reported receiving no training on how to treat their children, though they considered the importance of acquiring expertise to understand and treat the child. Mothers who do not have the necessary knowledge about their child's disability are not able to understand or accept the child's condition, leading to a denial of the problem, dissatisfaction, guilt and depression. It was noted in the study that proper preparation of the mother after the birth of her child, in terms of the disability can provide a better interaction and functioning of these families.

O propósito do estudo é estabelecer os conhecimentos, a dinâmica familiar e comunitária de mães de filhos com incapacidade que sirvam de base para a instrumentação de programas de intervenção. Participaram 42 mães com idades entre 19 e 49 anos (M = 31.14) de um Centro de Recuperação Infantil pertencentes à Secretaria de Defesa Nacional no México. Utilizou-se um roteiro de entrevista semiestruturada para explorar os conhecimentos, a dinâmica familiar e comunitária das famílias. As mães relataram que não receberam preparação de como cuidar seus filhos; porém, elas consideram a importância de adquirir conhecimentos especializados para entender e tratar ao menor. As mães que não têm os conhecimentos necessários sobre a incapacidade de seu filho não são capazes de entender nem aceitar a condição da criança, levando à negação do problema, inconformidade, culpa e depressão. Observou-se no estudo que uma preparação adequada da mãe depois do nascimento de seu filho, sobre a incapacidade, pode dar uma melhor interação e funcionamento destas famílias.

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Una de las funciones principales de la biotecnología ambiental es ocuparse del estudio de comunidades microbianas que proveen servicios esenciales para la sociedad. Más allá de las similitudes que presenta con la microbiología industrial y la agrícola, la biotecnología ambiental presenta peculiaridades, tales como los objetivos de proceso, las características de la biomasa y el tipo y modo de alimentación (sustratos), que la distinguen claramente de las otras disciplinas relacionadas. En este artículo se reseñan recientes avances en la ecología microbiana, la ecofisiología, la genómica y la ingeniería de procesos, para ilustrar cómo la integración de los nuevos conocimientos permite superar las limitaciones del análisis microbiológico clásico para entender, predecir y optimizar el funcionamiento de los procesos de tratamiento de efluentes.

One of the main functions of environmental biotechnology is to address the study of microbial communities that provide essential services to society. Beyond the similarities with industrial and agricultural microbiology, the unique features exhibited by environmental biotechnology, such as process objectives, biomass characteristics and type and mode of feeding (substrates), allow a clear distinction from the other related disciplines. Recent advances in microbial ecology, ecophysiology, genomics and process engineering are herein reviewed to illustrate how the integration of the new knowledge can help overcome the shortcomings of classic microbiological analyses to understand, predict and optimize the performance of wastewater treatment.

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The temporal variation in lake’s phytoplankton is important to understand its general biodiversity. For tropical lakes, it has been hypothesized that they follow a similar pattern as temperate ones, on a much accelerated pace; nevertheless, few case studies have tried to elucidate this. Most studies in Costa Rica have used a monthly sampling scheme and failed in showing the expected changes. In this study, the phytoplankton of the small Barvas’s crater lake was followed for more than three years, first with monthly and later with weekly samplings, that covered almost two years. Additional information on temperature and oxygen vertical profiles was obtained on a monthly basis, and surface temperature was measured during weekly samplings around noon. Results showed that in spite of its shallow condition (max. depth: 7m) and low surface temperature (11 to 19°C), the lake stratifies at least for brief periods. The phytoplankton showed both, rapid change periods, and prolonged ones of relative stasis. The plankton composition fluctuated between three main phases, one characterized by the abundance of small sized desmids (Staurastrum paradoxum, Cosmarium asphaerosporum), a second phase dominated by equally small cryptomonads (Chryptochrysis minor, Chroomonas sp.) and a third phase dominated by the green alga Eutetramorus tetrasporus. Although data evidenced that monthly sampling could miss short term events, the temporal variation did not follow the typical dry and rainy seasons of the region, or any particular annual pattern. Year to year variation was high. As this small lake is located at the summit of Barva Volcano and receives the influence from both the Caribbean and the Pacific weather, seasonality at the lake is not clearly defined as in the rest of the country and short term variations in the local weather might have a stronger effect than broad seasonal trends. The occurrence of this short term changes in the phytoplankton of small tropical lakes in response to weather variations needs to be further explored in other lakes. Rev. Biol. Trop. 58 (4): 1405-1419. Epub 2010 December 01.

Se ha especulado que la variación temporal del fitoplancton en lagos tropicales sigue un patrón similar al de lagos templados de forma más acelerada, pero pocos estudios de caso han abordado el tema. La mayoría de los estudios en lagos de Costa Rica se han basado en muestreos mensuales y no han logrado mostrar los cambios señalados. En este trabajo se estudió el fitoplancton del lago del volcán Barva por un periodo de más de tres años, al principio con un muestreo mensual y al final con un muestreo semanal por casi dos años. Mensualmente se hicieron perfiles verticales de temperatura y durante el periodo de muestreo semanal se registró la temperatura superficial cerca del medio día. A pesar de su condición somera (7m) y baja temperatura superficial, el lago se estratifica por periodos breves. El fitoplancton mostró tanto periodos de cambio rápido como periodos de estabilidad relativa. La composición fluctuó entre tres condiciones principales, la primera fase se caracteriza por la abundancia de desmidios (Staurastrum paradoxum, Cosmarium asphaerosporum), una segunda dominada por cryptomonadaceas (Chryptochrysis minor, Chroomonas sp.) y la tercera por Eutetramorus tetrasporus. Aunque fue evidente que los muestreos mensuales pueden obviar eventos de corta duración, la variación temporal no se ajustó a las estaciones de la zona. Dado que el lago se localiza en la cima del volcán Barva y recibe la influencia del clima tanto del Caribe como del Pacífico, la estacionalidad no está bien marcada en el sitio. Como resultado, las variaciones en el tiempo atmosférico local de corto plazo pueden tener un mayor efecto que los patrones estacionales del clima regional.

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A fish assemblage study was accomplished in different habitats of the Sorocaba River Basin. Fish were caught with gillnets, were weighed (weight total - g) and measured (standard length - mm). Several abiotic variables of selected sampling sites were measured in order to characterise their habitats in order to attempt establishing correlations with fish community traits. Fish numbers per species were adjusted to the lognormal and logseries species/abundance models The fish community totaled 38 species, distributed in 28 genera, 14 families and 4 orders. Diversity was calculated both in number and in weight and both presented higher values in better preserved sites. We did not detect any statistical differences between dry and rainy seasons. We also concluded that the abundance distribution was not influenced by abiotic variables.

Foi realizado um estudo das assembleias de peixes em diferentes ambientes aquáticos da bacia do Rio Sorocaba, São Paulo, Brasil. As espécies foram coletadas com redes de espera, sendo posteriormente identificadas. Foram obtidos dados relativos à abundância das espécies, pesos e comprimentos padrões, além de inúmeras variáveis abióticas das estações de amostragem para caracterização dos ambientes e correlação com a comunidade de peixes. A comunidade foi composta por 38 espécies de peixes, distribuídas em 28 gêneros, 14 famílias e 4 ordens. A comunidade de peixes se ajustou aos modelos lognormal e logsérie, característicos de comunidades com grandes riquezas e complexas, com múltiplas dimensões de nicho e superposição. A diversidade numérica apresentou maiores valores em estações mais preservadas, enquanto que para a diversidade em peso os maiores valores foram encontrados em locais mais preservados e também nos represamentos. Não foi detectada diferença nas diversidades entre as épocas seca e chuvosa. Para a comunidade de peixes da bacia do rio Sorocaba, a distribuição das abundâncias não foi influenciada pelas variáveis abióticas obtidas, devendo ser influenciadas pela estrutura do hábitat, não avaliada pelo presente trabalho.

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A fish assemblage study was accomplished in different habitats of the Sorocaba River Basin. Fish were caught with gillnets, were weighed (weight total - g) and measured (standard length - mm). Several abiotic variables of selected sampling sites were measured in order to characterise their habitats in order to attempt establishing correlations with fish community traits. Fish numbers per species were adjusted to the lognormal and logseries species/abundance models The fish community totaled 38 species, distributed in 28 genera, 14 families and 4 orders. Diversity was calculated both in number and in weight and both presented higher values in better preserved sites. We did not detect any statistical differences between dry and rainy seasons. We also concluded that the abundance distribution was not influenced by abiotic variables.

Foi realizado um estudo das assembleias de peixes em diferentes ambientes aquáticos da bacia do Rio Sorocaba, São Paulo, Brasil. As espécies foram coletadas com redes de espera, sendo posteriormente identificadas. Foram obtidos dados relativos à abundância das espécies, pesos e comprimentos padrões, além de inúmeras variáveis abióticas das estações de amostragem para caracterização dos ambientes e correlação com a comunidade de peixes. A comunidade foi composta por 38 espécies de peixes, distribuídas em 28 gêneros, 14 famílias e 4 ordens. A comunidade de peixes se ajustou aos modelos lognormal e logsérie, característicos de comunidades com grandes riquezas e complexas, com múltiplas dimensões de nicho e superposição. A diversidade numérica apresentou maiores valores em estações mais preservadas, enquanto que para a diversidade em peso os maiores valores foram encontrados em locais mais preservados e também nos represamentos. Não foi detectada diferença nas diversidades entre as épocas seca e chuvosa. Para a comunidade de peixes da bacia do rio Sorocaba, a distribuição das abundâncias não foi influenciada pelas variáveis abióticas obtidas, devendo ser influenciadas pela estrutura do hábitat, não avaliada pelo presente trabalho.