Hydropower affects fish trophic structure both downstream of the dam and upstream of the reservoir

Dams often cause drastic changes in freshwater environments and can compromise the quality and availability of food resources in rivers. This study aims to analyze the influence of a dam on the trophic structure of fish assemblages in lotic areas located both upstream and downstream of the Irapé Hydroelectric Power Plant. Fish sampling occurred before (2003 to 2005) and after (2011 to 2017) the impoundment, which began in 2006. The trophic structure and species composition before dam construction were similar upstream of the reservoir and downstream of the dam. After the building of the dam, both aspects of the assemblages changed along the lotic stretches - the upstream incurred an increase in biomass of detritivores and a decrease of piscivores and omnivores, while downstream went exactly the opposite, causing a differentiation between the two assemblages. Because lotic areas upstream of reservoirs are also impacted by river damming, efforts for impact mitigation should also focus on these areas.(AU)

Barragens causam mudanças drásticas em ambientes de água doce e podem comprometer a qualidade e a disponibilidade de recursos alimentares nos rios. Este estudo teve como objetivo analisar a influência de uma barragem na estrutura trófica da assembleia de peixes em áreas lóticas localizadas a montante e a jusante da usina hidrelétrica de Irapé. A amostragem de peixes ocorreu antes (2003 a 2005) e após (2011 a 2017) o fechamento das comportas, iniciado em 2006. A estrutura trófica e a composição das espécies antes da construção da barragem eram semelhantes a montante do reservatório e a jusante da barragem. Após a construção da barragem, ambos os aspectos das assembleias mudaram ao longo dos trechos lóticos - a montante ocorreu um aumento na biomassa de detritívoros e diminuição de piscívoros e onívoros, enquanto a jusante ocorreu exatamente o oposto, causando uma diferenciação entre as duas assembleias. Como as áreas lóticas a montante dos reservatórios também são impactadas por barramentos, esforços para mitigação de impactos também devem se concentrar nessas áreas.(AU)

Diet composition of abundant fish species in the shallow waters of the Todos os Santos Bay, Bahia, Brazil

Coastal habitats have great ecological importance with estuarine environments providing feeding sites for many fish species, especially during juvenile life stages. This study investigates the diet composition and trophic guild organization of the common and abundant ichthyofauna in shallow areas of the Todos os Santos Bay (TSB), Bahia, Brazil, and their relationships with environmental parameters. Six fish sampling campaigns were carried out in the shallow zones (infralittoral) of the Paraguaçu River estuary which encompasses the inner and outer (marine exposure) reaches of theTSB. The stomach contents of 1231 individualsbelonging to common and abundant species were examined. A total of 32 food items were identifiedand fish were into four trophic guilds: detritivores, zoobenthivores I, zoobenthivores II, and zooplanktivores. The relationship between the guilds and environmental parameters showed that zoobenthivores II and zooplanktivores guilds had a positive relationship with salinity and pH, explaining 86% of data variability, though only the salinity variable was significant. This study provides basic information about the diet composition of common and abundant species in the TSBand their organization into trophic guilds. In addition, demonstrates that shallow waters fish across all guilds have broadly similar diets, comprising food items that are usually associated with bottom waters.

Variation in hierarchical guild structure between two bird assemblages of a wetland in the Mexican Pacific / Variación en la estructura jerárquica de gremios entre dos ensambles de aves en un humedal del Pacífico de México

Abstract Neotropical wetlands comprise contrasting habitats with highly diverse avifauna, including herbivores, insectivores and carnivores, of both terrestrial and aquatic species. Therefore, comparisons between wetland bird assemblages based only on species identity may disregard turnover within ecological groups, and eclipse important variations between habitat types. We studied bird assemblages from mangrove and estuary habitat types from a coastal lagoon system in Oaxaca, Mexico. For this, we used 640 point counts to obtain data on bird species using those habitats between October 2009 and May 2012. We ascertained guild structure by classifying 139 species in a scalar hierarchy of two-levels: 17 key-resource guilds nested within seven trophic guilds. To evaluate variation in guild structure between habitat types, we contrasted richness and diversity across trophic guilds and tested for variation in abundance within key-resource guilds. We exposed a tendency of greater diversity within terrestrial guilds in mangrove and within aquatic guilds at the estuary. However, these differences were compensatory and neither richness nor diversity varied between habitat types in comparisons across the sets of trophic guilds. Parallel analyses at two hierarchical levels supported the theoretical prediction of greater change at lower levels. Herpetofauna, wood invertebrates, aquatic invertebrates and seeds emerged as dietary components that may explain the distribution of abundance in key-resource guilds. Although the guilds from mangrove and estuary produced comparable sets of richness and diversity values, the actual identity of guilds with high values varied between habitats. On the other hand, species abundance comparisons within guilds pinpointed specific associations with habitat types and this method represents a suitable strategy for identifying habitat preferences in complex wetland bird assemblages.

Resumen Los humedales neotropicales comprenden hábitats contrastantes con avifaunas altamente diversas que incluyen especies terrestres y acuáticas de herbívoros, insectívoros y carnívoros. Por lo cual, las comparaciones entre los ensambles avifaunísticos de los humedales basados únicamente en la identidad de especies podrían ignorar el recambio entre grupos ecológicos, y ocultar variaciones importantes entre tipos de hábitat. Nosotros estudiamos ensambles avifaunísticos de tipos de hábitat de manglar y estuario en un sistema lagunar de la costa de Oaxaca, México. Entre octubre 2009 y mayo 2012, utilizamos 640 puntos de conteo para determinar la estructura de gremios mediante la clasificación de 139 especies en una jerarquía escalar de dos niveles: 17 gremios de recursos claves anidados en siete gremios tróficos. Para evaluar la variación en la estructura jerárquica entre tipos de hábitat, contrastamos la riqueza y diversidad a través de gremios tróficos y probamos para variación en la abundancia dentro de gremios de recursos claves. Registramos una tendencia de mayor diversidad en gremios terrestres del manglar y en gremios acuáticos del estuario. Sin embargo, ésta variación fue compensatoria, ya que ni la riqueza específica ni la diversidad variaron entre los tipos de hábitat a través de los conjuntos de gremios tróficos. Un análisis paralelo de dos niveles jerárquicos soportó la predicción de un mayor recambio en niveles inferiores. La herpetofauna, los invertebrados en madera, los invertebrados acuáticos, y las semillas se presentaron como componentes alimenticios que podrían explicar la distribución de abundancia en los gremios de recursos claves. Aunque los gremios del manglar y estuario produjeron conjuntos comparables de valores de riqueza y diversidad, la identidad exacta de los gremios con valores altos variaba entre hábitats. Por otro lado, las comparaciones de abundancia dentro los gremios determinaron asociaciones específicas con tipos de hábitat y este método representa una estrategia apta para identificar las preferencias de hábitat en ensambles complejos de aves en humedales.

Attractiveness of Scarabaeinae (Coleoptera: Scarabaeidae) to different baits in the Brazilian Amazon region / Atracción de Scarabaeinae (Coleoptera: Scarabaeidae) por diferentes cebos en la región Amazónica brasileña

AbstractDung beetles (Coleoptera: Scarabaeidae: Scarabaeinae) are considered essential for enhancing the physicochemical characteristics of soils, principally by changing organic materials (e.g. dead animals, faeces, fruits e leaf litter). This study compared the species richness and abundance of dung beetles captured using various types of baits, to demonstrate attractiveness differences in variable habitats of the Brazilian Amazon. Samplings were carried out with pitfall traps baited with human faeces, rotten banana, rotten meat and a nonbaited trap, in February, March, June, September and October 2015. Habitats included native forests, agriculture areas, pastures and disturbed forests in different regeneration stages. A total of 13 736 Scarabaeinae beetles were captured, distributed over 98 species. Most individuals were captured using traps baited with faeces (76.7 % of individuals), followed by rotten meat baited traps (17.8 % of individuals), fermented banana baited traps (3.9 % of individuals) and finally by non-baited traps (1.6 % of individuals). A significant difference in attractiveness of the different baits used and habitats types was observed. Most of the captured assemblages were composed by coprophagous (42 %), generalist species (32 %), necrophagous (15 %) and none was classified as saprophagous. Approximately 54 % of the specimens were tunnelers, 25 % were rollers and 12 % were dwellers. The species of Scarabaeinae sampled in the region revealed qualitative and quantitative differences among their assemblages and the phytophysiognomies. The forest environments housed the greatest species richness observed, and a fraction of these is exclusive of those areas. We concluded that some species of Scarabaeinae have an important potential as disturbance indicators in the Amazonian ecosystem. Rev. Biol. Trop. 65 (3): 917-924. Epub 2017 September 01.

ResumenLos escarabajos peloteros (Coleoptera: Scarabaeidae: Scarabaeinae) son considerados fundamentales para la mejora de las características físico-químicas de los suelos, es decir, para la descomposición de materiales orgánicos (p. ej., animales muertos, heces, frutas y hojarasca). Este estudio compara la riqueza de especies y la abundancia de escarabajos peloteros, capturados utilizando diversos tipos de cebos, para demostrar diferencias en la atracción en hábitats de la Amazonía Brasileña. Se realizaron muestreos con trampas cebadas con heces humanas, plátano podrido, carne podrida y una trampa sin cebo. Los hábitats incluyen bosques nativos, zonas de agricultura, pastos y bosques alterados en diferentes fases de regeneración. Se capturaron un total de 13 736 escarabajos Scarabaeinae, distribuidos en 98 especies. La mayoría de los individuos fueron capturados en trampas cebadas con heces (76.7 % de los individos), seguido por las trampas con cebo de carne podrida (17.8 % de los individuos), trampas con cebo de plátano fermentado (3.9 % de los individuos) y finalmente por las trampas sin cebo (1.6 % de los individuos). Se observó una diferencia significativa en la atracción de los diferentes cebos y hábitats. La mayoría de la comunidad capturada estuvo compuesta de escarabajos coprófagos (42 %), especies generalistas (32 %) y necrófagos (15 %) y ninguno fue clasificado como saprófago. Aproximadamente, el 54 % de las muestras fueron excavadores, 25 % rodadores y 12 % residentes. Las especies de scarabaeinae muestreadas en la región revelaron diferencias cualitativas y cuantitativas entre sus ensamblajes y las fitofisionomías muestreadas. Los ambientes forestales albergaron la mayor riqueza de especies observada y una fracción de ellas es exclusiva de este entorno. Concluimos que algunas especies de Scarabaeinae tienen un potencial importante como indicadores de alteración en el ecosistema amazónico.

Comunidade de morcegos (Mammalia, Chiroptera) no Refúgio de Vida Silvestre Mata do Junco, Sergipe, nordeste do Brasil / Bats community (Mammalia, Chiroptera) in Refúgio de Vida Silvestre Mata do Junco, Sergipe, northeastern Brazil

A ordem Chiroptera é a segunda maior em riqueza de mamíferos no Brasil e a Mata Atlântica é o bioma com o melhor estado de conhecimento para esse grupo. Em Sergipe, estudos sobre quirópteros ainda são escassos, sendo necessário ampliar as pesquisas com esses animais. O presente trabalho teve como objetivo realizar o inventário de morcegos do Refúgio de Vida Silvestre Mata do Junco (RVSMJ), segunda maior reserva de Mata Atlântica do estado de Sergipe. As coletas foram realizadas durante duas noites por mês, entre fevereiro de 2011 a fevereiro de 2012, exceto junho. Com um esforço de captura de 21.168 m².h foram registrados 189 indivíduos de duas famílias e 14 espécies. Destas, Artibeus planirostris, Chiroderma doriae, Myotis nigricans, Phyllostomus discolor, Trachops cirrhosus e Trinycteris nicefori correspondem a novas ocorrências para a localidade, sendo T. nicefori novo registro para o estado. Phyllostomidae foi a família com maior riqueza e abundância e A. lituratus (N = 67), Carollia perspicillata (N = 45) e Dermanura cinerea (N = 45) foram as espécies mais abundantes. Essas três espécies juntas representam 83,0% dos indivíduos capturados; sendo caracterizadas como generalistas no uso do habitat e dieta. Com relação às guildas alimentares, a maioria das espécies é frugívora (57,1%), devido a metodologia e existência de áreas agrícolas presentes no RVSMJ. O registro de novas espécies para a localidade, juntamente com os parâmetros obtidos de riqueza, abundância e guilda alimentar, contribuem para o aumento do conhecimento dos quirópteros em Sergipe e podem servir de base para estratégias de conservação e manejo dessa área.

The order Chiroptera is the second in mammal species richness in Brazil and the Atlantic Forest is the biome with the best knowledge status for this group. In Sergipe, studies focused on bats are still scarce, being necessary to increase the research on such important taxon. This work aimed to conduct a bat inventory in the Refúgio de Vida Silvestre Mata do Junco (RVSMJ), which is the second largest reserve of Atlantic Forest in the state of Sergipe. Samples were obtained during two nights per month from February 2011 to February 2012, except in June. With a sampling effort of 21,168 m².h, we recorded 189 individuals of two families and 14 species. Among these, Artibeus planirostris, Chiroderma doriae, Myotis nigricans, Phyllostomus discolor, Trachops cirrhosus and Trinycteris nicefori are new occurrences for the location, being T. nicefori also new record for the state. Phyllostomidae was the richest and most abundant family, and A. lituratus (N = 67), Carollia perspicillata (N = 45), and Dermanura cinerea (N = 45) were the most abundant species. These three species accounted for 83.0% of all captured individuals, and were characterized as generalists in habitat use and diet. With respect to feeding guilds, most of the captured species are frugivores (57.1%), probably due to the methodology and existence of agricultural areas present in RVSMJ. The new records here assigned, along with the parameters obtained for richness, abundance and feeding guild, will increase our knowledge on the bats of Sergipe and can be used as a basis for conservation strategies and management at the studied site location.

Comunidade de Coleoptera de solo em remanescente de Mata Atlântica no Estado do Rio de Janeiro, Brasil / Comunity of soil fauna Coleoptera in the remnants of lowland Atlantic Forest in state of Rio de Janeiro, Brazil

A fauna do solo exerce importante papel nos processos ecológicos do ecossistema. Estudos sobre a composição e estrutura dessas comunidades são importantes para entender o seu funcionamento. Assim o objetivo deste trabalho foi avaliar a comunidade de Coleoptera, coletada mediante armadilhas de solo, quinzenalmente, durante o período de treze meses (08/2003-08/2004), na Mata do Mergulhão, Rio de Janeiro. Foram capturados 10.820 espécimes, representados por 24 famílias, sendo considerados abundantes Nitidulidae (4.782 indivíduos), Curculionidae (3.176 indivíduos), Scarabaeidae (2.019 indivíduos) e Staphylinidae (326 indivíduos), capturadas em todo período de coleta. De acordo com as guildas tróficas, os indivíduos das famílias coletados, podem ser agrupados em detritívoros (4.802 espécimes), herbívoros (3.218 espécimes), decompositores (2.019 espécimes), predadores (621 espécimes) e fungívoros (160 espécimes). Foi constatada maior ocorrência de detritívoros (44,4 por cento), herbívoros (29,7 por cento) e decompositores (18,7 por cento). Foram capturados 6.685 exemplares (61,8 por cento) no período de outubro/2003 a março/2004, na estação chuvosa, e 4.135 exemplares (38,2 por cento) na estação seca. Foram observadas maiores capturas nos meses de outubro e dezembro de 2003, e março de 2004.

The soil fauna plays an important role in the ecological function of an ecosystem and studies on the composition and structure of these communities are important to understand your functioning. The objective of our study was to evaluate of community of the soil fauna Coleoptera, collected bimonthly through pitfall trap, from August 2003 to August 2004. A total of 10,820 specimens from 24 families of Coleoptera were captured, but Nitidulidae (4,782 individuals), Curculionidae (3,176), Scarabaeidae (2,019) and Staphylinidae (326) were considered abundant families. According to the trophic guild, the collected individuals can be divided into detritivores (4,802 specimens), herbivores (3,218), decomposers (2,019), predators (621) and fungivoros (160). These results indicate no dominance of a single trophic group, however, the high occurrence of detritivores (44.4 percent), herbivores (29.7 percent) and decomposers (18.7 percent) was registered. About 61.8 percent (6,685 individuals) were captured during October 2003 to March 2004, a rainy period, and 38.2 percent (4,135) during the dry period indicating a pronounced seasonal difference in the relative abundance of individuals sampled. The high frequency of individuals was observed during the October and December, 2003, and March, 2004.