Variation in patterns of fish assemblage and their environmental correlates in a tropical river basin from the Gulf of Mexico slope

Understanding patterns of freshwater fish assemblage structure is key to protect them from ongoing human-induced threats to aquatic biodiversity. Yet, studies on associations between fish assemblages and habitat are lacking from many areas of high diversity in Middle America. We assessed fish assemblage structure and environmental associations from a portion of the Lacantún River sub-basin (Usumacinta River, Chiapas, Mexico). Based on environmental data and 17,462 individuals (56 species, 46 genera, and 22 families) captured from 13 sites sampled between 2017­2019, we found that stream order, distance to the Usumacinta, forest cover, temperature, and dissolved oxygen are key to explaining assemblage composition. Four clusters were found via multivariate regression tree analysis, with stream order and dissolved oxygen as defining variables. Our findings suggest that fish communities remain spatially structured even at small scales, in association to environmental gradients among habitats.(AU)

Comprender los patrones de estructuración en los ensamblajes de peces dulceacuícolas es una clave para protegerlos de las amenazas humanas a la biodiversidad acuática. No obstante, los estudios sobre asociaciones entre ensamblajes de peces y su hábitat son aún escasos en muchas áreas de alta diversidad de América Media. Evaluamos las asociaciones entre la estructura de los ensamblajes de peces y el ambiente de una porción de la subcuenca del Río Lacantún (cuenca del Río Usumacinta, Chiapas, México). Con base en datos ambientales y un total de 17,462 individuos (56 especies, 46 géneros, y 22 familias) capturados de 13 sitios muestreados entre 2017­2019, encontramos que el orden del cauce, distancia al Usumacinta, cobertura vegetal, temperatura y oxígeno disuelto son clave para explicar la composición de los ensamblajes. Cuatro grupos se detectaron utilizando un árbol de regresión multivariada, definidos por el orden del cauce y el oxígeno disuelto como variables definitorias. Nuestros hallazgos sugieren que las comunidades de peces retienen su estructura espacial aún a pequeñas escalas, en asociación a gradientes ambientales entre hábitats.(AU)

Occurrence and richness of arbuscular mycorrizal fungi in vineyards with grapevine decline and dieback symptoms / Ocorrência e riqueza de fungos micorrízicos arbusculares em vinhedos com sintomas de declínio e morte da videira

This research identified arbuscular mycorrhizal fungi (AMF) in rhizosphere soil of grapevines with Grapevine Death and Decline symptoms (GDD) or asymptomatic healthy (H) plants, and characterized the relationship of AMF communities with soil chemical attributes. The AMF spore number ranged from 287 to 432 spores 50 cm-³ in soil with GDD plants, and from 357 to 464 spores 50 cm-³ in H plants, with no differences among vineyards or between GDD and H plants within each vineyard. We detected 42 species and 17 genera, and most taxa belonged to Acaulosporaceae or Glomeraceae. Claroideoglomus etunicatum, Funneliformis mosseae, and Archaeospora trappei were the most frequent species in all vineyards. Soil chemical attributes were not determinant for the occurrence of most fungal species; although, Entrophospora infrequens, Diversispora sp1 and Diversispora sp2 were associated with a vineyard having high soil copper. Vineyards harbor highly diverse AMF communities, which are determined by location.

Este trabalho teve como objetivo identificar fungos micorrízicos arbusculares (FMA) em solo rizosférico de videiras com sintomas de declínio e morte da videira (D) e em plantas saudáveis (S), e caracterizar a relação das comunidades de FMA com atributos químicos do solo. O número de esporos de FMA variou de 287 a 432 esporos 50 cm-³ em solo em plantas D, e de 357 a 464 esporos 50 cm-³ em plantas S, sem diferenças entre vinhedos ou entre plantas D e S dentro de cada vinhedo. Detectamos 42 espécies e 17 gêneros, sendo que a maioria dos táxons pertencia a Acaulosporaceae ou Glomeraceae. Claroideoglomus etunicatum, Funneliformis mosseae e Archaeospora trappei foram as espécies mais frequentes em todos os vinhedos. Os atributos químicos do solo não foram determinantes para a ocorrência da maioria das espécies de fungos, embora Entrophospora infrequens, Diversispora sp1 e Diversispora sp2 estivessem associados a um vinhedo com alto teor de cobre do solo. Os vinhedos abrigam comunidades FMA altamente diversificadas, que são determinadas pela localização.

Bioactivity effect of Elephantopus scaber Linn. extracts against Spodoptera litura and the soil microbial community / Efeito da bioatividade de extratos de Elephantopus Scaber Linn. Em Spodoptera litura e na comunidade microbiana do solo

This study investigates the biopesticidal effects of Elephantopus scaber Linn. extract on mortality of Spodoptera litura, Plutella xylostella, and non-target organisms and investigate the impact on S. litura protein levels and soil microbial community structure. The experiment was performed using a completely randomized design. Methanol extracts from E. scaber leaves, at concentrations of 2%, 4%, 6%, 8%, 10%, and 12%, were tested for bioactivity against the 2nd-instar larva of S. litura, P. xylostella, and earthworms. Mortality rates of the larvae and worms were observed. The collected data were analyzed using analysis of variance (ANOVA), followed by probit and descriptive analysis. The results showed that methanol extracts of E. scaber (12%) influenced the highest mortality rates for both S. litura (93.35%) and P. xylostella (96.65%) with LC50 and LC80 of S. litura was 1.867 and 4.763; for P. xylostella were 4.488 and 7.92, respectively. However, the application of E. scaber biopesticide also influences earthworms' mortality rate. The 6% E. scaber extract resulted in 60% death of earthworms during a 20-daysperiod. In addition, higher concentrations of E. scaber extracts resulted in lower molecular weights and levels of S. litura proteins. The diversity and density of the soil microbial community also decreased by 6% concentration.

Este estudo tem como objetivo investigar os efeitos biopesticidas de Elephantopus scaber Linn. extrair na mortalidade de Spodoptera litura, Plutella xylostella e organismos não-alvo e investigar o impacto nos níveis de proteína de S. litura e na estrutura da comunidade microbiana do solo. Experimento realizado em delineamento inteiramente casualizado. Extratos de metanol de folhas de E. scaber, nas concentrações de 2%, 4%, 6%, 8%, 10% e 12%, foram testados para bioatividade contra a larva de 2º ínstar de S. litura, P. xylostella e minhocas. Taxas de mortalidade de larvas e vermes foram observadas. Os dados coletados foram analisados por meio de análise de variância (ANOVA), seguida de probit e análise descritiva. Os resultados mostraram que os extratos metanólicos de E. scabe r(12%) influenciaram as maiores taxas de mortalidade para S. litura (93,35%) e P. xylostella (96,65%) com CL50 e CL80 de S. litura foi de 1,867 e 4,763; para P. xylostella foram 4,488 e 7,92, respectivamente. No entanto, a aplicação de biopesticida de E. scaber também influencia a taxa de mortalidade de minhocas. O extrato de 6% de E. scaber resultou em 60% da morte de minhocas durante o período de 20 dias. Para além disso, maiores concentrações de extratos de E. scaber resultaram em menores pesos moleculares e níveis de proteínas de S. litura. A diversidade e a densidade da comunidade microbiana do solo também diminuíram na concentração de 6%.

Community ecology of the metazoan parasites of the Atlantic thread herring, Opisthonema oglinum (Lesueur, 1818) (Actinopterygii: Clupeidae) from the Sepetiba Bay, Rio de Janeiro, Brazil / Ecologia da comunidade dos metazoários parasitos da sardinha bandeira Opisthonema oglinum (Lesueur, 1818) (Actinopterygii: Clupeidae) da Baía de Sepetiba, Rio de Janeiro, Brasil

This study aimed to evaluate the parasitic fauna of Opisthonema oglinum (Lesueur, 1818) from Southeastern Brazil. Between September 2017 and March 2018, a total of 100 specimens of O. oglinum from the Sepetiba Bay, Rio de Janeiro, Brazil (22°54'S, 43°34'W) were examined. Ninety one specimens of O. oglinum were parasitized by at least one species of metazoan with a mean of 5.84 ± 7.98 parasites/fish. Seven species were collected: 2 digeneans, 2 monogeneans, 2 copepods and 1 nematode. The digenean Parahemiurus merus (Linton) was the most abundant and dominant species, representing 43% of metazoan parasites collected. The parasite species richness was positively correlated with the total length of the hosts. Only Neobomolochus elongatus Cressey showed a positive correlation between host's total length and parasite prevalence. The mean parasite species diversity was not correlated with host's total length, but significant differences among the mean parasite diversity between males and females was observed. Opisthonema oglinum represents a new host record for Caligus mutabilis Wilson, Hysterothylacium sp. and Cribomazocraes travassosi Santos and Kohn. The copepod N. elongatus is recorded for the first time on the Brazilian coast.

Este estudo teve como objetivo avaliar a fauna parasitária de Opisthonema oglinum (Lesueur, 1818) do Sudeste do Brasil. No período entre setembro de 2017 e março de 2018, um total de 100 espécimes de O. oglinum provenientes da Baía de Sepetiba, Rio de Janeiro, Brasil (22°54'S; 43°34'O), foram examinados. Noventa espécimes de O. oglinum estavam parasitados por pelo menos uma espécie de metazoário com média de 5,84 ± 7,98 parasitos/peixe. Sete espécies foram coletadas: 2 digenéticos, 2 monogenéticos, 2 copépodes e 1 nematoide. O digenético Parahemiurus merus (Linton) foi à espécie mais abundante e dominante, representando 43% dos metazoários parasitos coletados. A riqueza parasitária foi correlacionada com o comprimento total do hospedeiro. Apenas Neobomolochus elongatus Cressey apresentou correlação positiva entre o comprimento total do hospedeiro e a prevalência parasitária. A diversidade média de espécies de parasitos não apresentou correlação com o comprimento total do hospedeiro, mas foram observadas diferenças significativas entre a diversidade média de parasitos entre machos e fêmeas. Opisthonema oglinum representa um novo registro de hospedeiro para Caligus mutabilis Wilson, Hysterothylacium sp. e Cribomazocraes travassosi Santos and Kohn. O copépode N. elongatus é registrado pela primeira vez na costa Brasileira.

Community ecology of the metazoan parasites of the Atlantic thread herring, Opisthonema oglinum (Lesueur, 1818) (Actinopterygii: Clupeidae) from the Sepetiba Bay, Rio de Janeiro, Brazil / Ecologia da comunidade dos metazoários parasitos da sardinha bandeira Opisthonema oglinum (Lesueur, 1818) (Actinopterygii: Clupeidae) da Baía de Sepetiba, Rio de Janeiro, Brasil

This study aimed to evaluate the parasitic fauna of Opisthonema oglinum (Lesueur, 1818) from Southeastern Brazil. Between September 2017 and March 2018, a total of 100 specimens of O. oglinum from the Sepetiba Bay, Rio de Janeiro, Brazil (22°54'S, 43°34'W) were examined. Ninety one specimens of O. oglinum were parasitized by at least one species of metazoan with a mean of 5.84 ± 7.98 parasites/fish. Seven species were collected: 2 digeneans, 2 monogeneans, 2 copepods and 1 nematode. The digenean Parahemiurus merus (Linton) was the most abundant and dominant species, representing 43% of metazoan parasites collected. The parasite species richness was positively correlated with the total length of the hosts. Only Neobomolochus elongatus Cressey showed a positive correlation between host's total length and parasite prevalence. The mean parasite species diversity was not correlated with host's total length, but significant differences among the mean parasite diversity between males and females was observed. Opisthonema oglinum represents a new host record for Caligus mutabilis Wilson, Hysterothylacium sp. and Cribomazocraes travassosi Santos and Kohn. The copepod N. elongatus is recorded for the first time on the Brazilian coast.(AU)

Este estudo teve como objetivo avaliar a fauna parasitária de Opisthonema oglinum (Lesueur, 1818) do Sudeste do Brasil. No período entre setembro de 2017 e março de 2018, um total de 100 espécimes de O. oglinum provenientes da Baía de Sepetiba, Rio de Janeiro, Brasil (22°54S; 43°34O), foram examinados. Noventa espécimes de O. oglinum estavam parasitados por pelo menos uma espécie de metazoário com média de 5,84 ± 7,98 parasitos/peixe. Sete espécies foram coletadas: 2 digenéticos, 2 monogenéticos, 2 copépodes e 1 nematoide. O digenético Parahemiurus merus (Linton) foi à espécie mais abundante e dominante, representando 43% dos metazoários parasitos coletados. A riqueza parasitária foi correlacionada com o comprimento total do hospedeiro. Apenas Neobomolochus elongatus Cressey apresentou correlação positiva entre o comprimento total do hospedeiro e a prevalência parasitária. A diversidade média de espécies de parasitos não apresentou correlação com o comprimento total do hospedeiro, mas foram observadas diferenças significativas entre a diversidade média de parasitos entre machos e fêmeas. Opisthonema oglinum representa um novo registro de hospedeiro para Caligus mutabilis Wilson, Hysterothylacium sp. e Cribomazocraes travassosi Santos and Kohn. O copépode N. elongatus é registrado pela primeira vez na costa Brasileira.(AU)

Baixa riqueza zooplanctônica indicando condições adversas de seca e eutrofização em um reservatório no Nordeste do Brasil / Low zooplankton richness indicating adverse drought and eutrophication conditions in a reservoir in northeastern Brazil

This work characterized the zooplankton and the environmental variables of the Canoas reservoir (Assaré, Ceará, Brazil) through eight consecutive monthly collections during a period of intense drought. Zooplankton samples were collected by vertical plots of 50 µm plankton net at three longitudinally distributed points. Five species were found: Brachionus calicyflorus Pallas, 1938 (Brachionidae: Rotifera), Diaphanosoma spinulosum Herbst, 1967 (Sididae: Cladocera), Thermocyclops decipiens Kiefer, 1929 and T. inversus Kiefer, 1936 (Cyclopoida: Copepoda), and Notodiaptomus cearensis Wright, 1936 (Calanoida: Copepoda). Thermocyclops decipiens had the highest relative abundance, followed by N. cearensis and B. calicyflorus. The spatial and temporal variation of the zooplankton community can be explained by most of the environmental variables associated with N. cearensis and B. calicyflorus, while T. decipiens was not associated with any of them. The low species richness and dominance of T. decipiens and B. calicyflorus may be a reflection of the high trophic condition of the reservoir during severe drought, and N. cearensis is also associated with these more adverse conditions.(AU)

Esse trabalho caracterizou o zooplâncton e as variáveis ambientais do reservatório Canoas (Assaré, Ceará, Brasil) através de oito coletas consecutivas mensais, durante um período de estiagem intensa. Amostras de zooplâncton foram coletadas com arrastos verticais de rede de plâncton de 50 µm em três pontos distribuídos longitudinalmente. Foram encontradas cinco espécies: Brachionus calicyflorus Pallas, 1938 (Brachionidae: Rotifera), Diaphanosoma spinulosum Herbst, 1967 (Sididae: Cladocera), Thermocyclops decipiens Kiefer, 1929 e T. inversus Kiefer, 1936 (Cyclopoida: Copepoda), e Notodiaptomus cearensis Wright, 1936 (Calanoida: Copepoda). Thermocyclops decipiens apresentou a maior abundância relativa, seguido de N. cearensis e B. calicyflorus. A variação espacial e temporal da comunidade zooplanctônica pode ser explicada pela maioria das variáveis ambientais associadas a N. cearensis e B. calicyflorus, enquanto T. decipiens não se associou a nenhuma delas. A baixa riqueza de espécies e a dominância de T. decipiens e B. calicyflorus podem ser reflexos da elevada condição trófica do reservatório, em período de estiagem intensa, e N. cearensis está associado também com essas condições mais adversas.(AU)

Community ecology of the metazoan parasites of the Atlantic thread herring, Opisthonema oglinum (Lesueur, 1818) (Actinopterygii: Clupeidae) from the Sepetiba Bay, Rio de Janeiro, Brazil

Abstract This study aimed to evaluate the parasitic fauna of Opisthonema oglinum (Lesueur, 1818) from Southeastern Brazil. Between September 2017 and March 2018, a total of 100 specimens of O. oglinum from the Sepetiba Bay, Rio de Janeiro, Brazil (22°54'S, 43°34'W) were examined. Ninety one specimens of O. oglinum were parasitized by at least one species of metazoan with a mean of 5.84 ± 7.98 parasites/fish. Seven species were collected: 2 digeneans, 2 monogeneans, 2 copepods and 1 nematode. The digenean Parahemiurus merus (Linton) was the most abundant and dominant species, representing 43% of metazoan parasites collected. The parasite species richness was positively correlated with the total length of the hosts. Only Neobomolochus elongatus Cressey showed a positive correlation between host's total length and parasite prevalence. The mean parasite species diversity was not correlated with host's total length, but significant differences among the mean parasite diversity between males and females was observed. Opisthonema oglinum represents a new host record for Caligus mutabilis Wilson, Hysterothylacium sp. and Cribomazocraes travassosi Santos and Kohn. The copepod N. elongatus is recorded for the first time on the Brazilian coast.

Resumo Este estudo teve como objetivo avaliar a fauna parasitária de Opisthonema oglinum (Lesueur, 1818) do Sudeste do Brasil. No período entre setembro de 2017 e março de 2018, um total de 100 espécimes de O. oglinum provenientes da Baía de Sepetiba, Rio de Janeiro, Brasil (22°54S; 43°34O), foram examinados. Noventa espécimes de O. oglinum estavam parasitados por pelo menos uma espécie de metazoário com média de 5,84 ± 7,98 parasitos/peixe. Sete espécies foram coletadas: 2 digenéticos, 2 monogenéticos, 2 copépodes e 1 nematoide. O digenético Parahemiurus merus (Linton) foi à espécie mais abundante e dominante, representando 43% dos metazoários parasitos coletados. A riqueza parasitária foi correlacionada com o comprimento total do hospedeiro. Apenas Neobomolochus elongatus Cressey apresentou correlação positiva entre o comprimento total do hospedeiro e a prevalência parasitária. A diversidade média de espécies de parasitos não apresentou correlação com o comprimento total do hospedeiro, mas foram observadas diferenças significativas entre a diversidade média de parasitos entre machos e fêmeas. Opisthonema oglinum representa um novo registro de hospedeiro para Caligus mutabilis Wilson, Hysterothylacium sp. e Cribomazocraes travassosi Santos and Kohn. O copépode N. elongatus é registrado pela primeira vez na costa Brasileira.

Baixa riqueza zooplanctônica indicando condições adversas de seca e eutrofização em um reservatório no Nordeste do Brasil / Low zooplankton richness indicating adverse drought and eutrophication conditions in a reservoir in northeastern Brazil

This work characterized the zooplankton and the environmental variables of the Canoas reservoir (Assaré, Ceará, Brazil) through eight consecutive monthly collections during a period of intense drought. Zooplankton samples were collected by vertical plots of 50 µm plankton net at three longitudinally distributed points. Five species were found: Brachionus calicyflorus Pallas, 1938 (Brachionidae: Rotifera), Diaphanosoma spinulosum Herbst, 1967 (Sididae: Cladocera), Thermocyclops decipiens Kiefer, 1929 and T. inversus Kiefer, 1936 (Cyclopoida: Copepoda), and Notodiaptomus cearensis Wright, 1936 (Calanoida: Copepoda). Thermocyclops decipiens had the highest relative abundance, followed by N. cearensis and B. calicyflorus. The spatial and temporal variation of the zooplankton community can be explained by most of the environmental variables associated with N. cearensis and B. calicyflorus, while T. decipiens was not associated with any of them. The low species richness and dominance of T. decipiens and B. calicyflorus may be a reflection of the high trophic condition of the reservoir during severe drought, and N. cearensis is also associated with these more adverse conditions.

Esse trabalho caracterizou o zooplâncton e as variáveis ambientais do reservatório Canoas (Assaré, Ceará, Brasil) através de oito coletas consecutivas mensais, durante um período de estiagem intensa. Amostras de zooplâncton foram coletadas com arrastos verticais de rede de plâncton de 50 µm em três pontos distribuídos longitudinalmente. Foram encontradas cinco espécies: Brachionus calicyflorus Pallas, 1938 (Brachionidae: Rotifera), Diaphanosoma spinulosum Herbst, 1967 (Sididae: Cladocera), Thermocyclops decipiens Kiefer, 1929 e T. inversus Kiefer, 1936 (Cyclopoida: Copepoda), e Notodiaptomus cearensis Wright, 1936 (Calanoida: Copepoda). Thermocyclops decipiens apresentou a maior abundância relativa, seguido de N. cearensis e B. calicyflorus. A variação espacial e temporal da comunidade zooplanctônica pode ser explicada pela maioria das variáveis ambientais associadas a N. cearensis e B. calicyflorus, enquanto T. decipiens não se associou a nenhuma delas. A baixa riqueza de espécies e a dominância de T. decipiens e B. calicyflorus podem ser reflexos da elevada condição trófica do reservatório, em período de estiagem intensa, e N. cearensis está associado também com essas condições mais adversas.

Baixa riqueza zooplanctônica indicando condições adversas de seca e eutrofização em um reservatório no Nordeste do Brasil

ABSTRACT This work characterized the zooplankton and the environmental variables of the Canoas reservoir (Assaré, Ceará, Brazil) through eight consecutive monthly collections during a period of intense drought. Zooplankton samples were collected by vertical plots of 50 µm plankton net at three longitudinally distributed points. Five species were found: Brachionus calicyflorus Pallas, 1938 (Brachionidae: Rotifera), Diaphanosoma spinulosum Herbst, 1967 (Sididae: Cladocera), Thermocyclops decipiens Kiefer, 1929 and T. inversus Kiefer, 1936 (Cyclopoida: Copepoda), and Notodiaptomus cearensis Wright, 1936 (Calanoida: Copepoda). Thermocyclops decipiens had the highest relative abundance, followed by N. cearensis and B. calicyflorus. The spatial and temporal variation of the zooplankton community can be explained by most of the environmental variables associated with N. cearensis and B. calicyflorus, while T. decipiens was not associated with any of them. The low species richness and dominance of T. decipiens and B. calicyflorus may be a reflection of the high trophic condition of the reservoir during severe drought, and N. cearensis is also associated with these more adverse conditions.

RESUMO Esse trabalho caracterizou o zooplâncton e as variáveis ambientais do reservatório Canoas (Assaré, Ceará, Brasil) através de oito coletas consecutivas mensais, durante um período de estiagem intensa. Amostras de zooplâncton foram coletadas com arrastos verticais de rede de plâncton de 50 µm em três pontos distribuídos longitudinalmente. Foram encontradas cinco espécies: Brachionus calicyflorus Pallas, 1938 (Brachionidae: Rotifera), Diaphanosoma spinulosum Herbst, 1967 (Sididae: Cladocera), Thermocyclops decipiens Kiefer, 1929 e T. inversus Kiefer, 1936 (Cyclopoida: Copepoda), e Notodiaptomus cearensis Wright, 1936 (Calanoida: Copepoda). Thermocyclops decipiens apresentou a maior abundância relativa, seguido de N. cearensis e B. calicyflorus. A variação espacial e temporal da comunidade zooplanctônica pode ser explicada pela maioria das variáveis ambientais associadas a N. cearensis e B. calicyflorus, enquanto T. decipiens não se associou a nenhuma delas. A baixa riqueza de espécies e a dominância de T. decipiens e B. calicyflorus podem ser reflexos da elevada condição trófica do reservatório, em período de estiagem intensa, e N. cearensis está associado também com essas condições mais adversas.

Species richness and community composition of sphingid moths (Lepidoptera: Sphingidae) along an elevational gradient in southeast Peru

A clear low-elevation skewed unimodal richness pattern is presented for hawkmoths in Southeast Peru. Several hypotheses offer plausible explanations for such a distribution. The effects of water-energy dynamics are partially supported by a strong correlation between temperature and species richness at higher elevations. Further, hypotheses of plant diversity influences on hawkmoth ranges are supported by species richness peaking in transitional habitats. Sphingid subfamilies do not appear to be influenced by habitat type or elevational factors, such as temperature. This may make subfamily analysis a poor means of characterizing sphingid community composition unless study sites vary in the level of disturbance. This study documents 134 species in 23 genera of Sphingidae from five Southeastern Peru sites from the 7,545 specimens collected for the study.

Species richness and community composition of sphingid moths (Lepidoptera: Sphingidae) along an elevational gradient in southeast Peru

A clear low-elevation skewed unimodal richness pattern is presented for hawkmoths in Southeast Peru. Several hypotheses offer plausible explanations for such a distribution. The effects of water-energy dynamics are partially supported by a strong correlation between temperature and species richness at higher elevations. Further, hypotheses of plant diversity influences on hawkmoth ranges are supported by species richness peaking in transitional habitats. Sphingid subfamilies do not appear to be influenced by habitat type or elevational factors, such as temperature. This may make subfamily analysis a poor means of characterizing sphingid community composition unless study sites vary in the level of disturbance. This study documents 134 species in 23 genera of Sphingidae from five Southeastern Peru sites from the 7,545 specimens collected for the study.(AU)

Do natural disturbances have significant effects on sandy beach macrofauna of Southeastern Brazil?

The role of morphodynamic features such as grain size, swash climate and wave action on the macrofauna of beaches are well-known. However, few studies have investigated natural disturbances as potential drivers of temporal community variations. In southeastern Brazil, we sampled the intertidal macrofauna of two sandy beaches to test whether seasonal disturbances as the frequency of storm wave events (SWE) and rainfall have significant influence on their composition and abundance. The macrofauna assemblage differed significantly between the rainy and the dry seasons, but rainfall was not the main driver of community changes, although both beaches are in the vicinity of extensive river plumes. Actually, SWE explained most macrofauna richness overtime, with positive effects. Our results point to the importance of learning more about the effects of poorly studied disturbances on macrofaunal communities, and based on them we strongly recommend including these seasonal phenomena when monitoring sandy beaches.

Colonization of benthic invertebrates on artificial and natural substrate in a Neotropical lotic environment in Southern Brazil

The objective of this research was to validate the colonization process on natural and artificial substrates by benthic invertebrates in a tropical stream in South Brazil. The samples were performed in July and August-2012, and 32 samplers were used, being 16 natural and 16 artificial substrates. In each sample, two replicas were taken for each substrate at the 2th, 4th, 7th, 14th, 21th28th, 35th and 42thdays of colonization. The organisms were identified to the lowest possible taxonomic level. In both substrates 3,070 benthic invertebrates were detected, of which 1,753 individuals were collected on the natural substrate, and 1,317 on the artificial substrate. From the identified taxa 8.5% were not dominant (Anacroneuria, Orthocladiinae, Tupiara, Smicridea, Baetodes, Tupiperla, Macrogynoplax, Gripopteryx, Cylloepus, Macrelmis, Microcylloepus, Hetaerina, Argia, Coryphaeschna, Atopsyche, Pomacea, Corydalus, Leptohyphes and Eccoptura), and31.5% were dominant (Tanypodinae, Chironominae, and Paragripopteryx). The genus Simulium was very common, dominant and abundant, representing 65% of the collected individuals. No significant difference was found in the abundance and species composition between artificial and natural substrates. On the natural substrate, the higher colonization index was at the 35th day with 459 individuals, and the lowest was at the 14th day, with 87. On the artificial substrate the highest index was at the 42thday with 337 individuals, and the lowest was at the 4th day, with 85. Both natural and artificial substrates are efficient in characterizing the benthic community. In the evaluation of the ecological succession, it was not possible to observe a pattern that described the process, since the composition was nearly constant throughout the study period.

Do natural disturbances have significant effects on sandy beach macrofauna of Southeastern Brazil?

The role of morphodynamic features such as grain size, swash climate and wave action on the macrofauna of beaches are well-known. However, few studies have investigated natural disturbances as potential drivers of temporal community variations. In southeastern Brazil, we sampled the intertidal macrofauna of two sandy beaches to test whether seasonal disturbances as the frequency of storm wave events (SWE) and rainfall have significant influence on their composition and abundance. The macrofauna assemblage differed significantly between the rainy and the dry seasons, but rainfall was not the main driver of community changes, although both beaches are in the vicinity of extensive river plumes. Actually, SWE explained most macrofauna richness overtime, with positive effects. Our results point to the importance of learning more about the effects of poorly studied disturbances on macrofaunal communities, and based on them we strongly recommend including these seasonal phenomena when monitoring sandy beaches.(AU)

Las Podostemaceae como hábitat para los macroinvertebrados en arroyos de Misiones (Argentina)

Las Podostemaceae son importantes componentes de las mallas tróficas de los ambientes reófilos pero su importancia como hábitat para los invertebrados es poco conocida. En este estudio se analizó la variación temporal de la abundancia y riqueza de taxa de los macroinvertebrados asociados a Podostemum distichum y Podostemum muelleri (Malpighiales: Podostemaceae) en dos arroyos de bajo orden durante diferentes estaciones del año. La abundancia total promedio difirió entre fechas de muestreo, pero no entre arroyos. Se registraron 14 familias de macroinvertebrados distribuidas en 9 órdenes en ambos arroyos. El Análisis de Escalamiento Multidimensional No Métrico (NMDS) reflejó también diferencias en el patrón estacional. Tanto el coeficiente de similitud como el de complementariedad, indican que ambos arroyos fueron muy similares en cuanto a la composición de las familias de macroinvertebrados. Las especies de Podostemaceae dominantes en cada arroyo constituyen hábitats de diversidad intermedia de acuerdo al índice de diversidad utilizado.(AU)

Podostemaceae are important components of the trophic networks of rheophilic environments but their importance as habitats for invertebrates is little known. In this study, the abundance and taxa richness of macroinvertebrate assemblages associated with Podostemum distichum and Podostemum muelleri (Malpighiales: Podostemaceae) in two low order streams were analyzed across seasons. Mean macroinvertebrate abundance differed significantly among seasons but did not differ between streams. Nine orders of macroinvertebrates were recorded in both streams, comprising 14 families. Non- metric multidimensional scaling (NMDS) reflected some differences in the seasonal pattern, too. The coefficient of similarity and the complementarity indicate that both streams were very similar in terms of the composition of the macroinvertebrate families. The dominant Podostemceae species in each stream constitute intermediate diversity habitats for macroinvertebrates according to the diversity index used.(AU)

Las Podostemaceae como hábitat para los macroinvertebrados en arroyos de Misiones (Argentina)

Las Podostemaceae son importantes componentes de las mallas tróficas de los ambientes reófilos pero su importancia como hábitat para los invertebrados es poco conocida. En este estudio se analizó la variación temporal de la abundancia y riqueza de taxa de los macroinvertebrados asociados a Podostemum distichum y Podostemum muelleri (Malpighiales: Podostemaceae) en dos arroyos de bajo orden durante diferentes estaciones del año. La abundancia total promedio difirió entre fechas de muestreo, pero no entre arroyos. Se registraron 14 familias de macroinvertebrados distribuidas en 9 órdenes en ambos arroyos. El Análisis de Escalamiento Multidimensional No Métrico (NMDS) reflejó también diferencias en el patrón estacional. Tanto el coeficiente de similitud como el de complementariedad, indican que ambos arroyos fueron muy similares en cuanto a la composición de las familias de macroinvertebrados. Las especies de Podostemaceae dominantes en cada arroyo constituyen hábitats de diversidad intermedia de acuerdo al índice de diversidad utilizado.

Podostemaceae are important components of the trophic networks of rheophilic environments but their importance as habitats for invertebrates is little known. In this study, the abundance and taxa richness of macroinvertebrate assemblages associated with Podostemum distichum and Podostemum muelleri (Malpighiales: Podostemaceae) in two low order streams were analyzed across seasons. Mean macroinvertebrate abundance differed significantly among seasons but did not differ between streams. Nine orders of macroinvertebrates were recorded in both streams, comprising 14 families. Non- metric multidimensional scaling (NMDS) reflected some differences in the seasonal pattern, too. The coefficient of similarity and the complementarity indicate that both streams were very similar in terms of the composition of the macroinvertebrate families. The dominant Podostemceae species in each stream constitute intermediate diversity habitats for macroinvertebrates according to the diversity index used.

Las Podostemaceae como hábitat para los macroinvertebrados en arroyos de Misiones (Argentina)

RESUMEN Las Podostemaceae son importantes componentes de las mallas tróficas de los ambientes reófilos pero su importancia como hábitat para los invertebrados es poco conocida. En este estudio se analizó la variación temporal de la abundancia y riqueza de taxa de los macroinvertebrados asociados a Podostemum distichum y Podostemum muelleri (Malpighiales: Podostemaceae) en dos arroyos de bajo orden durante diferentes estaciones del año. La abundancia total promedio difirió entre fechas de muestreo, pero no entre arroyos. Se registraron 14 familias de macroinvertebrados distribuidas en 9 órdenes en ambos arroyos. El Análisis de Escalamiento Multidimensional No Métrico (NMDS) reflejó también diferencias en el patrón estacional. Tanto el coeficiente de similitud como el de complementariedad, indican que ambos arroyos fueron muy similares en cuanto a la composición de las familias de macroinvertebrados. Las especies de Podostemaceae dominantes en cada arroyo constituyen hábitats de diversidad intermedia de acuerdo al índice de diversidad utilizado.

ABSTRACT Podostemaceae are important components of the trophic networks of rheophilic environments but their importance as habitats for invertebrates is little known. In this study, the abundance and taxa richness of macroinvertebrate assemblages associated with Podostemum distichum and Podostemum muelleri (Malpighiales: Podostemaceae) in two low order streams were analyzed across seasons. Mean macroinvertebrate abundance differed significantly among seasons but did not differ between streams. Nine orders of macroinvertebrates were recorded in both streams, comprising 14 families. Non- metric multidimensional scaling (NMDS) reflected some differences in the seasonal pattern, too. The coefficient of similarity and the complementarity indicate that both streams were very similar in terms of the composition of the macroinvertebrate families. The dominant Podostemceae species in each stream constitute intermediate diversity habitats for macroinvertebrates according to the diversity index used.

Organization of fish assemblages in blackwater Atlantic Forest streams

This study aimed to determine whether fish species occupy different mesohabitats, as defined by specific criteria of substrate types in Atlantic Forest blackwater streams. We sampled fourteen coastal blackwater rivers along the coast of São Paulo State, Brazil, during the low-flow season (June-September/2016). For each stream, we selected three mesohabitat types (sand, leaf-litter and trunks) in a 100 m river stretch. We sampled 41 mesohabitats, 31 of which contained fish, resulting in 15 species. When multivariate analysis of variance (MANOVA) was applied to the mesohabitat abiotic variables, no significant differences were indicated between them. ANOSIM for species density and biomass and Redundancy Analyses (RDAs) for species density, biomass and fish community indexes showed similar patterns of community structure among mesohabitats. Nevertheless, fish biomass, diversity and richness were associated with such unique environmental features as low shading and shallow habitats. The observed dispersion among mesohabitats suggests that these communities are subject to some level of disturbance, which may affect the value of patches as refugia. Thus, the sharing of these mesohabitat patches among species may represent an opportunistic strategy to maximize the use of available resources for these low density populations living in these unique environments.(AU)

O objetivo do estudo foi testar se espécies de peixes ocupam diferentes mesohabitats definidos por critérios específicos de tipos de substrato em riachos de águas pretas de Mata Atlântica. Durante a estação de baixa vazão (junho-setembro/2016), foram amostrados quatorze riachos costeiros de águas pretas no litoral de São Paulo, Brasil. Para cada riacho, selecionamos três tipos de mesohabitats (areia, folhiço e troncos) em um trecho de rio de 100 m. Amostramos 41 mesohabitats, dos quais 31 com peixes, resultando em 15 espécies. A análise de variância multivariada (MANOVA) aplicada às variáveis abióticas dos mesohabitats, não indicou diferenças significativas entre estes. A ANOSIM para densidade de espécies e biomassa e as Análises de Redundância (RDAs) para densidade de espécies, biomassa e índices da comunidade indicaram padrões semelhantes da estrutura da comunidade entre mesohabitats. No entanto, a biomassa, a diversidade e a riqueza de peixes estiveram associadas a características ambientais específicas tais como habitats rasos e sombreados. Os resultados sugerem que estas comunidades estejam sujeitas a certo nível de perturbação, o que afeta o valor dos mesohabitats como refúgios. Assim, a utilização dos diferentes mesohabitats entre as espécies pode representar uma estratégia oportunista para maximizar o uso de recursos por essas populações de baixa densidade que vivem nestes ambientes peculiares.(AU)

Effects of the introduction of an omnivorous fish on the biodiversity and functioning of an upland Amazonian lake / Efeitos da introdução de um peixe onívoro sobre a biodiversidade e funcionamento de um lago de altitude amazônico

The introduction of nonnative species is one of the main threats to freshwater ecosystems. Although omnivory and intraguild predation are common in those systems, little is known about the effects of introduced omnivorous fish on pelagic and littoral communities. This study tested predictions of food-web theory regarding the effects of omnivorous fish introduction on previously fishless lakes in the Amazonian uplands of Serra dos Carajás, Pará, Brazil. The trophic structure of two similar lakes, one with and the other without the introduced omnivorous fish Astyanax bimaculatus, was compared using a data series of biotic variables collected from both lakes twice a year from 2010 to 2013. Zooplankton was more abundant in the lake with fish, and the zooplankton composition differed between lakes. Phytoplankton richness and chlorophyll-a were higher in the lake with the introduced fish than in the fishless lake regardless of phosphorus limitation. For the benthic macroinvertebrate communities, species richness and biomass were higher in the fishless lake. Our results also indicate that A. bimaculatus has the potential to link pelagic and littoral habitats through nutrient cycling. The differences observed between the studied lakes are consistent with predictions from food-web theory regarding the effects of multichain omnivorous fish on trophic dynamics. Despite limitations regarding replication at the ecosystem level, it is possible to infer from our findings that the introduction of an omnivorous fish might have changed lake overall functioning.(AU)

A introdução de espécies não nativas é uma ameaça aos ecossistemas de água doce. Embora a onivoria e a predação intraguilda sejam comuns nesses sistemas, os efeitos da introdução de peixes onívoros nas comunidades pelágicas e litorâneas é pouco conhecido. Nós testamos as previsões da teoria da teia trófica considerando os efeitos da introdução de um peixe onívoro em um lago previamente desprovido de peixes localizado na Serra dos Carajás, Pará, Brasil. A estrutura trófica em dois lagos similares, um com a presença do peixe onívoro introduzido Astyanax bimaculatus, e outro sem peixes, foi comparada através de uma série de dados bióticos amostrados entre 2010 e 2013. A comunidade zooplanctônica foi mais abundante no lago com peixe e sua composição diferiu entre os dois lagos. Apesar da limitação por fósforo no lago com peixe, a riqueza do fitoplâncton e a concentração de clorofila-a foram maiores nesse lago. A comunidade de macroinvertebrados bentônicos apresentou maior riqueza e biomassa no lago sem peixe. Nossos resultados também indicam que A. bimaculatus tem o potencial de acoplar as comunidades litorâneas e pelágicas através da reciclagem de nutrientes. Apesar das limitações relacionadas à ausência de replicação no nível de ecossistemas, nós argumentamos que o nosso estudo mostra que a introdução do peixe onívoro pode ter causado mudanças no funcionamento do lago.(AU)

Organization of fish assemblages in blackwater Atlantic Forest streams

This study aimed to determine whether fish species occupy different mesohabitats, as defined by specific criteria of substrate types in Atlantic Forest blackwater streams. We sampled fourteen coastal blackwater rivers along the coast of São Paulo State, Brazil, during the low-flow season (June-September/2016). For each stream, we selected three mesohabitat types (sand, leaf-litter and trunks) in a 100 m river stretch. We sampled 41 mesohabitats, 31 of which contained fish, resulting in 15 species. When multivariate analysis of variance (MANOVA) was applied to the mesohabitat abiotic variables, no significant differences were indicated between them. ANOSIM for species density and biomass and Redundancy Analyses (RDAs) for species density, biomass and fish community indexes showed similar patterns of community structure among mesohabitats. Nevertheless, fish biomass, diversity and richness were associated with such unique environmental features as low shading and shallow habitats. The observed dispersion among mesohabitats suggests that these communities are subject to some level of disturbance, which may affect the value of patches as refugia. Thus, the sharing of these mesohabitat patches among species may represent an opportunistic strategy to maximize the use of available resources for these low density populations living in these unique environments.(AU)

O objetivo do estudo foi testar se espécies de peixes ocupam diferentes mesohabitats definidos por critérios específicos de tipos de substrato em riachos de águas pretas de Mata Atlântica. Durante a estação de baixa vazão (junho-setembro/2016), foram amostrados quatorze riachos costeiros de águas pretas no litoral de São Paulo, Brasil. Para cada riacho, selecionamos três tipos de mesohabitats (areia, folhiço e troncos) em um trecho de rio de 100 m. Amostramos 41 mesohabitats, dos quais 31 com peixes, resultando em 15 espécies. A análise de variância multivariada (MANOVA) aplicada às variáveis abióticas dos mesohabitats, não indicou diferenças significativas entre estes. A ANOSIM para densidade de espécies e biomassa e as Análises de Redundância (RDAs) para densidade de espécies, biomassa e índices da comunidade indicaram padrões semelhantes da estrutura da comunidade entre mesohabitats. No entanto, a biomassa, a diversidade e a riqueza de peixes estiveram associadas a características ambientais específicas tais como habitats rasos e sombreados. Os resultados sugerem que estas comunidades estejam sujeitas a certo nível de perturbação, o que afeta o valor dos mesohabitats como refúgios. Assim, a utilização dos diferentes mesohabitats entre as espécies pode representar uma estratégia oportunista para maximizar o uso de recursos por essas populações de baixa densidade que vivem nestes ambientes peculiares.(AU)