DIFERENCIAÇÃO MORFOLÓGICA ENTRE POPULAÇÕES DE Corydoras aeneus GILL (1858) (SILURIFORMES, CALLICHTHYIDAE) EM RIACHOS DAS BACIAS HIDROGRÁFICAS DOS RIOS PARANÁ E PARAGUAI

This study analyzes the existence of differentiation in morphology of isolated populations of Corydoras aeneus (Gill, 1858). Fourteen morphometric characters were used to evaluate the morphology of 14 isolated populations of the basins of the Paraná and Paraguay rivers. We verified the existence of morphological differentiation with the aid of discriminant function analysis. We used the Mantel test to see if there was a correlation between morphological similarity and geographical distance. After, we conducted an analysis between morphological similarity and the environmental characteristics of streams. The results indicated that there is significant difference in the morphology of the species between sites (Wilk’s Lambda= 0,02; F(182,935)= 1,92; p<0,001). There is significant correlation between the morphology of the species and characteristics of listed sites (Mantel r= 0,62, p= 0,01). The differences in the morphology of the populations were consistent with the differences in the characteristics of the studied streams. Thus, over evolutionary time individuals were selected who had characteristics that conferred greater adaptation to environmental characteristics, independently of the geographic distance between the populations studied.Keywords: Geographic Variation; Fishes; Streams; Morphometry.No presente estudo analisamos a existência de diferenciação na morfologia de populações isoladas de Corydoras aeneus (Gill, 1858). Quatorze caracteres morfométricos foram utilizados para a avaliação na morfologia de 14 populações isoladas das bacias dos rios Paraná e Paraguai. Verificamos a existência de diferenciação morfológica com auxílio da Análise de Função Discriminante. Utilizamos o teste de Mantel para observar se existia relação entre a similaridade morfológica e a distância geográfica. Após, realizamos uma análise de  entre a similaridade morfológica e as características ambientais dos riachos. Constatamos, que existe diferença significativa na morfologia das espécies entre os locais (Wilk’s Lambda= 0,02; F(182,935)= 1,92; p<0,001). Existe correlação significativa entre a morfologia das espécies e as características dos locais coletados (Mantel r= 0,62, p= 0,01). As diferenças na morfologia das populações foram congruentes com as diferenças nas características dos riachos estudados. Desta forma, ao longo do tempo evolutivo foram selecionados os indivíduos que apresentavam características que conferiam maior adaptação às características ambientais, independente da distância geográfica entre estas populações estudadas.Palavras-chave: variação geográfica, peixes, riachos, morfometria

Interspecific Differentiation in Heavy Metals Concentration in Fishes of the Apa River, Upper Paraguay River Basin

Heavy metals concentration in fishes are important indicator geomorphological or environmental integrity in aquatic habitats. Aiming to evaluate metal concentration in fish muscles in Apa River, upper Paraguay basin, we analyzed 124 individuals of eight fish species at Cachoeira do Apa district (Porto Murtinho) from 2013 to 2014 belonging to Brycon hilarii, Leporinus friderici, Megaleporinus macrocephalus, Megaleporinus obtusidens, Piaractus mesopotamicus, Prochilodus lineatus, Pterodoras granulosus and Salminus brasiliensis. The samples were frozen and in the laboratory the musculature was removed, the samples were digested using the triacid method, and later the concentration of heavy metals was quantified in a flame atomic absorption spectrophotometer. There is a significant difference in the concentration of metals in fish (F=27.79, p<0.001). Considering the multivariate comparison of studied species, we observed that P. lineatus have a more different pattern of metal concentration, with P. granulosus also presenting a different pattern of others species. None species presented the concentration of metals above the limit defined by Brazilian legislation, however, species differed in their metal concentrations according to the position in the water column and feeding, suggesting that the integrated assessment of the concentration of metals may be an indicator of ecological differences in the obtaining of resources by species in aquatic communities. DOI: http://dx.doi.org/10.17807/orbital.v10i1.104

METACOMUNIDADES EM RIACHOS: UMA ABORDAGEM CIENCIOMÉTRICA

Metacomunidades são definidas como conjuntos de comunidades locais interligadas por dispersão e potenciais interações.  Abordagem que incorpora as interpretações ecológicas em diferentes escalas, e também aplicadas à ecologia de riachos, que possuem sistemas interessantes tanto nos fatores bióticos e abióticos. Refletindo esta visão, o presente estudo evidencia as principais tendências das publicações científicas e suas abordagens, através do levantamento cienciométrico referente às metacomunidades em riachos utilizando a base de dados ISI Web of Knowledge. Observamos aumento no número das publicações, nos grupos biológicos entre os anos decorrentes e nas palavras-chave. Indicando uma importância relativa do tema

Spatial connectivity of aquatic macrophytes and flood cycle influence species richness of an ant community of a Brazilian floodplain

Despite the environmental and economic importance of Pantanal, there are few studies quantifying the influence of sazonality and spatial variation on biological diversity in this ecosystem. In this context, the present work aimed to study the assemblage of ants associated with macrophytes during the flood and dry period of Paraguay river, in marginal environments in the Pantanal of Porto Murtinho, Mato Grosso do Sul. We observed a wide variation in the temporal distribution of the diversity of the assemblages of ants, since from 37 species, 36 occurred in the dry and 20 in the flood period. Of the total of macrophyte species observed, in only 12.5% we found a more specific correlation with ants that were nesting in spaces provided by plants representing a total of 10.52% of the species analized.