14 research outputs found
Variação espacial e temporal na diversidade e composição de espécies de peixes em riachos da bacia do Rio Ivinhema, Alto Rio Paranå
Survey of fish species from plateau streams of the Miranda River Basin in the Upper Paraguay River Region, Brazil
New records and checklist of aquatic and semi-aquatic Heteroptera (Insecta: Hemiptera: Gerromorpha and Nepomorpha) from the Southern region of Mato Grosso do Sul, Brazil
Assembléias de peixes associados às macrófitas aquåticas em ambientes alagåveis do Pantanal de Poconé, MT, Brasil
Factors affecting assemblage attributes of freshwater Oligochaeta in Neotropical shallow floodplain lakes
Trophic ecology of Hemigrammus marginatus Ellis, 1911 (Characiformes, Characidae) in a conserved tropical stream
Variação espacial e temporal na diversidade e composição de espécies de peixes em riachos da bacia do Rio Ivinhema, Alto Rio Paranå
Com o objetivo de descrever o padrĂŁo espacial e temporal na diversidade e composição de espĂ©cies de peixes em sete riachos da bacia do rio Ivinhema, alto rio ParanĂĄ, amostragens mensais foram realizadas entre janeiro e dezembro/2002. Quarenta e seis espĂ©cies de peixes foram encontradas, sendo estimada a ocorrĂȘncia de cinqĂŒenta e cinco espĂ©cies nestes riachos. A riqueza de espĂ©cies e a equitabilidade nĂŁo apresentaram variaçÔes temporais significativas, contudo, foi constatada variação espacial (entre riachos) significativa. A AnĂĄlise de Similaridade (ANOSIM) sugere que existe somente variação espacial significativa na composição de espĂ©cies. A riqueza de espĂ©cies foi significativamente correlacionada com a largura (r = 0,80) e a profundidade do riacho (r = 0,78). A equitabilidade apresentou correlação significativa somente com o nĂșmero mĂ©dio de indivĂduos coletados (r = -0,91). Apenas a largura dos riachos influenciou significativamente a distribuição das principais espĂ©cies de peixes nos riachos amostrados. Algumas espĂ©cies como H. marginatus, A. dentatus, M. sanctaefilomenae ocorreram principalmente em riachos mais volumosos e A. fasciatus e B. stramineus ocorreram principalmente em riachos rasos e com elevada velocidade da correnteza, indicando a importĂąncia das caracterĂsticas hidrolĂłgicas na distribuição das espĂ©cies. As caracterĂsticas fĂsicas dos riachos sĂŁo mais importantes que as variaçÔes temporais na organização das assemblĂ©ias de peixes dos riachos amostrados
Tropical headwater streams and the role of non-native species on fish assemblageâs diversity
Non-native species cause several impacts on freshwater biodiversity, but studies focusing on the Neotropical streamâs biota are still incipient. We used a data set of 586 headwater streamâs fish assemblages from the Brazilian Upper ParanĂĄ ecoregion to test whether the presence/absence of non-native species affect: species richness (S), functional diversity (MPD) and taxonomic diversity (Î+). We compared diversity patterns of fish assemblages formed only by native species against those of assemblages formed by native and non-native species (Scenario 1); then, we removed non-native species from their original assemblages and recalculated their diversity values to compare them with those of fish assemblages formed only by native species again (Scenario 2). We also investigated: (1) whether non-nativeâs fish assemblages are associated with land use, topographic and watercourse connectivity variables; (2) fish ecological traits-environment relationship. In Scenario 1, S was higher in assemblages with the presence of non-native species, while in Scenario 2, both S and MPD were higher in assemblages where non-native species were removed. Non-native species were not directly related to land use, topographic or connectivity variables and most of them had a similar response to the environment when compared with native species. Findings show that non-native fish species are related to high-rich assemblages in headwaters, and they increase species richness and the functional redundancy of assemblages, decreasing functional diversity. Moreover, in most cases, native and non-native species seem to respond similarly to the environmental influence on their occurrence