61 research outputs found
Assessing the impacts of the introduced channel catfish <i>Ictalurus punctatus</i> using the comparative functional response approach
Feeding ecology of Rivulus luelingi (Aplocheiloidei: Rivulidae) in a Coastal Atlantic Rainforest stream, southern Brazil
Trophic strategy of Atlantirivulus riograndensis (Cyprinodontiformes: Rivulidae), a non-annual rivulid threatened by extinction, in a perennial environment, Brazil)
Temporal and ontogenetic variations in feeding habits of Hollandichthys multifasciatus (Teleostei: Characidae) in coastal Atlantic rainforest streams, southern Brazil
A new species of the characid genus Hollandichthys Eigenmann from coastal rivers of southern Brazil (Teleostei: Characiformes) with a discussion on the diagnosis of the genus
Ecologia e ontogenia da alimentação de Astyanax janeiroensis (Osteichthyes, Characidae) de um riacho costeiro do Sudeste do Brasil
Habitat heterogeneity on feeding habit of two sympatric and congeneric characidae fishes in two tropical reservoirs
Evidence of niche partitioning under ontogenetic influences among three morphologically similar siluriformes in small subtropical streams
Ontogenetic influences in patterns of niche breadth and feeding overlap were investigated in three species of Siluriformes (Heptapterus sp., Rhamdia quelen and Trichomycterus poikilos) aiming at understanding the species coexistence. Samplings were conducted bimonthly by electrofishing technique from June/2012 to June/2013 in ten streams of the northwestern state of Rio Grande do Sul, Brazil. The stomach contents of 1,948 individuals were analyzed by volumetric method, with 59 food items identified. In general Heptapterus sp. consumed a high proportion of Aegla sp., terrestrial plant remains and Megaloptera; R. quelen consumed fish, and Oligochaeta, followed by Aegla sp.; while the diet of T. poikilos was based on Simuliidae, Ephemeroptera and Trichoptera. Specie segregation was observed in the NMDS. Through PERMANOVA analysis feeding differences among species, and between a combination of species plus size classes were observed. IndVal showed which items were indicators of these differences. Niche breadth values were high for all species. The niche breadth values were low only for the larger size of R. quelen and Heptapterus sp. while T. poikilos values were more similar. Overall the species were a low feeding overlap values. The higher frequency of high feeding overlap was observed for interaction between Heptapterus sp. and T. poikilos. The null model confirmed the niche partitioning between the species. The higher frequency of high and intermediate feeding overlap values were reported to smaller size classes. The null model showed resource sharing between the species/size class. Therefore, overall species showed a resource partitioning because of the use of occasional items. However, these species share resources mainly in the early ontogenetic stages until the emphasized change of morphological characteristics leading to trophic niche expansion and the apparent segregation observed
Colorful invasion in permissive Neotropical ecosystems: establishment of ornamental non-native poeciliids of the genera Poecilia/Xiphophorus (Cyprinodontiformes: Poeciliidae) and management alternatives
Seasonal variation in fish trophic networks in two clear-water streams in the Central Llanos region, Venezuela
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