Localization and Distribution of Two Invasive Alien Species Eichhornia crassipes and Echinocloa pyramidalis in the Pool Malebo Eco-region, Democratic Republic of the Congo

Aim: To study the distribution of two invasive alien plants and associated plants as well as their distribution in the Malebo Pool eco-region. Methodology: The study was carried out by direct observation by circulating on a motorized canoe. Plant samples were randomly harvested (n=6) in August 2020 depends on the sites. Plant species identification was performed on the field, and those species of which the identification was difficult, were brought to the laboratory for proper identification according to APG III. Results: 19 species, including two Pteridophytes and 17 Angiosperms, belonging to 19 families and 12 orders were identified. The site of Molondo was the most diversified with 15 plant species, followed respectively by the sites of Mipongo (13 species), Japon (12 species) and Kingabwa (07 species). The plant species Ludwigia abyssinica A. Rich., Ipomoea aquatica Forsk, Eichhornia crassipes (Mart), Pistia stratiotes L, Echinochloa pyramidalis (Lam) and Salvinia molesta D.S. Mitchell were present in all four prospected sites. E. pyramidalis and E. crassipes constitute a serious threat for the environment and are source of erosion/loss of aquatic biodiversity. Physiologically, these species form a mono-specific carpet and eliminate native or autochthonous species of aquatic flora.Conclusions and Suggestions: The invasion of alien species is a consequence of human activities and a concern, as it affects all sectors of society. These plants can alter, disrupt, and degrade many ecosystem services like the disturbing of habitats and the alteration of the environmental and biological conditions around them. They can also reduce light and diversity of native aquatic plant species. Controlling invasive alien species is thus a challenge for the Congolese society. Political decision-makers are therefore invited to take appropriate measures for managing and protecting the local aquatic flora and valorize the invasive plants as potential medicinal remedy.

A predictive multimetric index based on macroinvetebrates for Atlantic Forest wadeable streams assessment / Índice Multimétrico Preditivo baseado em macroinvertebrados para avaliação de riachos vadeáveis da Mata Atlântica

Abstract: Multimetric Indices (MMIs) have been widely applied for ecological assessment in freshwater ecosystems. Most MMIs face difficulties when scaling up from small spatial scales because larger scales usually encompass great environmental variability. Covariance of anthropogenic pressures with natural environmental gradients can be a confounding factor in assessing biologic responses to anthropogenic pressures. This study presents the development and validation of a predictive multimetric index to assess the ecological condition of Atlantic Forest wadeable streams using benthic macroinvertebrates. To do so, we sampled 158 sites for the index development. We adjusted each biological metric to natural variation through multiple regression analyses (stepwise-forward) and considered that the residual distribution describes the metric variation in the absence of natural environmental influence. For metric selection we considered normal distribution, variation explained by the models, redundancy between metrics and sensitivity to differentiate reference from impaired sites. We selected five metrics to the final index: total richness, %MOLD, %Coleoptera, EPT richness and Chironomidae abundance. The residuals were transformed into probabilities and the final index was obtained through the mean of these probabilities. This index performed well in discriminating the impairment gradient and it showed a high correlation (r = 0.85, p <0.001) with a specific index developed for a particular basin indicating a similar sensitivity. This index can be used to assess wadeable streams ecological condition in Atlantic Forest biome, so we believe that this type of approach represents an important step towards the application of biomonitoring tools in Brazil.

Resumo: Índices Multimétricos (MMIs) são ferramentas amplamente aplicadas ao monitoramento ecológico de ecossistemas aquáticos continentais. A maior dificuldade na utilização dos MMIs em amplas escalas espaciais consiste no aumento da variabilidade ambiental associado ao aumento da escala. A covariância entre os impactos antropogênicos e o gradiente ambiental natural pode atuar como fator de confusão, dificultando a avaliação das respostas biológicas às pressões antropogênicas. Este estudo consiste no desenvolvimento e validação de um índice multimétrico preditivo para avaliar a condição ecológica de riachos vadeáveis da Mata Atlântica, utilizando macroinvertebrados bentônicos. Todas as métricas biológicas foram ajustadas a variação natural através da análise de regressão múltipla ("stepwise-forward") e a distribuição dos resíduos foi utilizada para descrever variação de cada métrica na ausência de gradiente ambiental natural. Para a seleção das métricas foram considerados critérios de normalidade da distribuição, variação explicada pelos modelos, redundância entre métricas e sensibilidade para diferenciar gradiente de impacto. Foram selecionadas cinco métricas para compor o índice final: riqueza total, %MOLD (Mollusca+Diptera), %Coleoptera, riqueza de EPT (Ephemeroptera+Plecoptera+Trichoptera) e abundância de Chironomidae. Os resíduos das métricas selecionadas foram transformados em probabilidades e o valor final do índice foi obtido através da média dessas probabilidades. O índice teve ótimo desempenho em discriminar o gradiente de impacto e mostrou alta correlação (r = 0.85, p <0.001) com um índice desenvolvido especificamente para uma das bacias, indicando sensibilidade similar. O índice desenvolvido nesse trabalho pode ser utilizado em todo o estado do Rio de Janeiro e acreditamos que este tipo de abordagem constitui uma contribuição importante para o desenvolvimento e implementação de um programa de monitoramento biológico no Brasil.

Composición y estructura de peces de la microcuenca del río Anchique, Tolima, Colombia / Composition and structure of the fish community structure in the Anchique River sub-basin, Tolima, Colombia

Resumen La microcuenca del río Anchique se ubica en el municipio de Natagaima (Tolima) y drena directamente al río Magdalena, la distribución y abundancia de los peces está influenciada por múltiples factores a escalas temporales y espaciales, el objetivo del estudio es describir la estructura y composición de la comunidad íctica a lo largo del río y probar la hipótesis de que estas comunidades varían a nivel temporal y espacial. Se realizaron dos muestreos en altas y bajas lluvias, y se establecieron cuatro estaciones, colectándose 625 ejemplares y 36 especies. No se encontraron diferencias estadísticamente significativas entre algunas variables ambientales del río a nivel temporal, según la prueba Kruskal-wallis. Los valores de los índices de complejidad estructural y composición del sustrato, muestran que la estación E4 presentó los valores más altos, además fue la estación con mayor riqueza y diversidad según los números de Hill. El análisis de correspondencia canónica evidenció que el sustrato, complejidad y ancho del cauce influyeron de forma significativa en la composición y distribución de los peces. La comunidad íctica del río no presentó variación de la diversidad y riqueza temporalmente, pero si espacialmente, lo cual podría deberse a que cada estación presentó características estructurales diferentes.

Abstract The distribution and abundance of fish is influenced by multiple factors at temporal and spatial scales, and their community composition represent good river integrity indicators. The main objective of this study was to describe the composition and structure of fish assemblages along the Anchique river sub-basin (that drains to Magdalena river), and to test the hypothesis that these communities vary temporally and spatially. For this, four sites (E1, E2, E3 and E4) were sampled along the river (from river birthplace to Magdalena river), during the periods of high and low waters, in 2014. In each site, longitudinal transects (100 m long x 2 m wide, 60 min) were established and fishing was made with both electrofishing and trawl (10 m x 1 m, 0.05 m) nets. Fish samples were fixed and transported to the laboratory for posterior taxonomic identification with the use of keys; fish diversity and structure composition were calculated with the use of standard models. Besides, substrate composition and environmental variables were also considered. A total of 652 fish belonging to 36 species were recorded; high water showed higher values (325 fish with 32 species) than low water period (300 fish with 31 species). Siluriformes was dominant (51 %), followed by Characiformes (32 %), Gymnotiformes (5 %), Cyprinidontiformes and Cichliformes (6 %). Most abundant families were Characidae (28.3 %; 9 spp.), Loricariidae (23.4 %; 8 spp.) and Trichomycteridae (15.0 %; 2 spp.). Kruskal-Wallis test indicated that there is no significant difference among some environmental variables at the temporal level. The values of structural complexity and substrate composition indices showed that E4 had the highest values (0.8), followed by E1 (0.6), and E2 and E3 (0.4). Moreover, E4 had the highest richness and diversity, according to Hill's number. The canonical correspondence analysis showed that the substrate, and the complexity and width of the river channel, had a significant influence on fish composition and distribution. The fish community richness and diversity did not change temporarily, but did spatially, which could be related to the different structural features of sampling sites. Rev. Biol. Trop. 66(1): 336-351. Epub 2018 March 01.

Seasonal variation in fish trophic networks in two clear-water streams in the Central Llanos region, Venezuela

Food webs are not static entities; consumer resource interactions vary in both time and space, which complicates depiction and comparisons of food web structures. We estimated fish assemblage structure and diets in two clear-water streams in the Venezuelan Llanos region (Charcote and Charcotico) and constructed trophic networks (sub-webs defined by fishes as the principal consumers) during four periods of the annual flood pulse. As stream conditions changed from high-water to low-water, we hypothesized that: 1) the piscivore-non-piscivore ratio would increase; 2) dietary diversity would decrease; 3) interspecific dietary overlap would decline; 4) fewer allochthonous food items would be consumed; and 5) food-web connectance would increase. The piscivore-non-piscivore abundance ratio was higher in both streams during the low-water period. Dietary diversity declined as water levels dropped and availability of aquatic habitats and resources declined, but interspecific dietary overlap was not lower. Contrary to our hypothesis, average interspecific dietary overlap increased at Charcote as the dry season progressed, even though dietary overlap among species was significantly lower than expected by chance. We did not find strong support for our hypotheses regarding seasonal patterns of consumption of allochthonous resources and food web connectance, both of which revealed little seasonal variation.(AU)

Redes alimentares não são entidades estáticas; interações entre consumidores e recursos variam no tempo e no espaço, o que complica as representações das estruturas de redes alimentares. Nós estimamos a estrutura da assembléia de peixes e dieta em dois riachos de água clara na região venezuelana dos Llanos (Charcote e Charcotico) e construímos redes tróficas (sub-redes definidas por peixes como os principais consumidores) para quatro períodos do pulso anual de inundação. À medida que as condições dos riachos mudam de águas altas para águas baixas, nós hipotetizamos que: 1) a razão piscívoros e não piscívoros irá aumentar; 2) a diversidade da dieta irá diminuir; 3) a sobreposição alimentar interespecífica irá diminuir; 4) menos itens alimentares alóctones serão consumidos; e 5) a conectância da teia alimentar irá aumentar. A razão da abundância de piscívoros e não piscívoros foi maior em ambos riachos durante a estação de águas baixas. A diversidade da dieta declinou à medida que as águas baixavam e a disponibilidade de habitats aquáticos e recursos declinavam, mas a sobreposição alimentar interespecífica não foi menor. Contrária à nossa hipótese, a média de sobreposição alimentar interespecífica aumentou no Charcote à medida que a estação cheia progrediu, mesmo com a sobreposição alimentar significativamente menor do que o esperado ao acaso. Não encontramos forte suporte para nossas hipóteses relacionadas aos padrões sazonais de consumo de recursos alóctones e conectância da cadeia trófica, os quais revelaram pouca variação sazonal.(AU)

Mercury in Pelecanus occidentalis of the Cispata bay, Colombia / Mercurio en Pelecanus occidentalis de la bahía de Cispatá, Colombia

Objective. Assessment the total concentration of mercury in the liver and feathers of Pelecanus occidentalis of the Cispata bay, Colombia. Materials and methods. Mercury concentrations in liver and feather of Pelecanus occidentalis residents in the Cispata bay - Colombia were evaluated by digestion with an acidic mixture of H2SO4-HNO3 and KMnO4 to eliminate organic matter. The concentration of mercury was determined by the Atomic Absorption - Cold Vapor method (CVAAS). Results. Total mercury levels found in this study were higher in feathers (0.31-9.17 mgHg/kg) than in the liver (0.63-6.29 mgHg/kg), being higher than those reported in other seabirds studies. Conclusions. The high levels of total mercury in feathers and liver can be explained by the feeding habits of the organisms under study, showing the utility of feathers as a potential non-invasive tool for the monitoring of the ecosystem and thereby preventing the sacrifice of specimens.

Objetivo. Evaluar las concentraciones de mercurio total en hígado y plumas de Pelecanus occidentalis de la Bahía de Cispatá, Colombia. Materiales y métodos. Se evaluó la concentración de mercurio en hígado y plumas de Pelecanus occidentalis pertenecientes a la bahía de Cispatá - Colombia, por digestión con una mezcla ácida de H2SO4-HNO3 y KMnO4 para eliminar la materia orgánica. La concentración de mercurio fue determinada por el método de Absorción Atómica - Vapor Frio (CVAAS). Resultados. Los valores de mercurio total fueron más altos en plumas (0.31-9.17 mgHg/kg) que en hígado (0.63-6.29 mgHg/kg), siendo mayores a los reportados en otros estudios de aves marinas. Conclusiones. Las altas concentraciones de mercurio total en plumas e hígado pueden ser atribuidas a la dieta de los organismos estudiados; demostrando la utilidad de las plumas como herramienta potencial no invasiva de monitoreo del ecosistema y evitando con ello el sacrificio de los individuos.

Plesiomonasshigelloides and Aeromonadaceae family pathogens isolated from marine mammals of Southern and Southeastern Brazilian coast / Plesiomonasshigelloides e patógenos da família Aeromonadaceae isolados de mamíferos marinhos da costa sul e sudeste do Brasil

The aquatic environment is the habitat of many microorganisms, including Plesiomonasshigelloides and Aeromonas species which are pathogenic to human and animals. In the present investigation, we evaluated the occurrence of these pathogens from marine mammals beached or accidentally captured by fishing net in southeastern (RJ) and southern (RS) coastal Brazilian regions. A total of 198 swabs from 27 specimens of marine mammals, including 11 different species, were collected by DEENSP and GEMARS-CECLIMAR/UFRGS Institutes and sent to LRNCEB/IOC/FIOCRUZ. The samples were enriched in Alkaline Peptone Water (APW) added with 1 percent of sodium chloride (NaCl), APW plus 3 percent NaCl and incubated at 37ºC for 18-24 hours. Following, samples were streaked onto Pseudomonas-Aeromonas Selective Agar Base (GSP Agar) and suspected colonies were biochemically characterized. The results revealed 114 strains, including ten Aeromonas species and P.shigelloides. The main pathogens isolated were A.veronii biogroup veronii (19.3 percent), A. caviae (12.3 percent), A. hydrophila (9.6 percent) and P.shigelloides (7 percent). The pathogens were isolated in both coastal and offshore marine mammals. These data point the importance of epidemiological surveillance and microbiological monitoring and reinforce the need to implement environmental protection programs, especially related to endangered cetacean species.

O ambiente aquático é o habitat de vários microrganismos, incluindo Plesiomonasshigelloides e espécies de Aeromonas, os quais são patogênicos para o homem e os animais. Na presente investigação, foi avaliada a ocorrência destes patógenos a partir de swabs coletados de mamíferos marinhos encalhados ou capturados acidentalmente em redes de pesca nas regiões costeiras do sudeste (RJ) e sul (RS) do Brasil. O total de 198 swabs de 27 espécimes de mamíferos marinhos, incluindo 11 espécies distintas, foi coletado por profissionais dos institutos DEENSP, GEMARS-CECLIMAR/UFRGS e enviado ao LRNCEB/IOC/FIOCRUZ. Em seguida, as amostras foram submetidas a enriquecimento em Água Peptonada Alcalina (APA) adicionada de 1 por cento de cloreto de sódio (NaCl) e APA com 3 por cento de NaCl (37ºC/18-24 h). Posteriormente, as amostras foram semeadas em meio Agar Seletivo para Pseudomonas-Aeromonas (Agar GSP) e as colônias suspeitas submetidas à caracterização bioquímica. Um total de 114 cepas foram identificadas, incluindo dez espécies de Aeromonas e P.shigelloides. Os principais patógenos isolados foram A.veronii biogrupo veronii (19,3 por cento), A. caviae (12,2 por cento), A. hydrophila (9,6 por cento) e Plesiomonasshigelloides (7 por cento). Os patógenos foram encontrados tanto em espécies de mamíferos marinhos costeiros como oceânicos. Esses dados apontam para a importância da vigilância epidemiológica e monitoramento microbiológico, além de reforçar a necessidade de implantação de programas de proteção ambiental, particularmente relacionados aos mamíferos marinhos ameaçados de extinção.