Abstract Coexistence of ecomorphologically similar species in diverse Neotropical ecosystems has been a focus long-term debate among ecologists and evolutionary biologists. Such coexistence can be promoted by trophic plasticity seasonal changes omnivorous feeding. We combined stomach content stable isotope analyses to determine how variation resource availability influences the consumption assimilation resources two syntopic fish species, Psalidodon aff. gymnodontus P. bifasciatus , Lower...

AbstractInvasions of freshwater habitats by marine fishes provide exceptional cases habitat-driven biological diversification. Freshwater make up less than 1% aquatic but contain ∼50% fish species. However, while the dominant group (Otophysi) is older that most (Percomorphaceae), it morphologically diverse. Classically, scientists have invoked differences in tempo and/or mode evolution to explain such unequal morphological We tested for evidence these phenomena superfamily Cottoidea...

Abstract Body shape variation should play a central role in determining the feeding ability of fish species. We tested whether variations resource use sympatric and closely related species could be explained by differences ecologically relevant metrics, such as body morphology, trophic apparatus or combinations thereof. Fish were sampled at 14 sampling sites from Pelotas River tributaries, Upper Uruguay, Brazil. The stomach contents five Characidae ( Astyanax Bryconamericus ) analysed...

Abstract The persistence of diverse communities and functioning ecosystems under increasing anthropogenic pressure relies on food web rewiring the ability animals to expand or change their diet in disturbed ecosystems. We combined a suite tracing techniques study trophic plasticity omnivorous fishes, ecomorphologically similar species with high competition potential, across different human land uses subtropical streams. found that proportion native forest cover, associated intensive use,...

This study evaluated feeding patterns and ontogenetic variations in a non-native fish species (Plagioscion squamosissimus) an isolated lake the Upper Paraná River floodplain. Quarterly samplings were performed from April 2005 to February 2006 using plankton nets capture larvae, seining for juveniles, gill trammel adults. Stomach contents (n = 378) examined according volumetric method which volume of each food item was estimated graduated test tubes or glass counting plate. During early...

This study focused on intra and interspecific variations in the diet of small species Pelotas River, upper Uruguay River ecoregion. We tested hypothesis that five characids coexist via resource partitioning. Samplings were performed quarterly between August 2013 May 2014 at 14 sites basin, using gillnets different mesh sizes, seines, cast nets electrofishing. In this study, contents 1,253 stomachs analysed from Astyanax dissensus , A. paris saguazu xiru Bryconamericus patriciae . The main...

This study investigated the morphological and dietary relationships of fish assemblage in a stream with an endemic fauna low species richness. The ichthyofauna was sampled quarterly from September 2011 to July 2012, through electrofishing technique. stomach contents 419 individuals belonging seven were analyzed by volumetric method, ecomorphological traits 30 specimens each estimated. main food items consumed detritus, aquatic terrestrial insects, other invertebrates. We observed levels...

Abstract The fish fauna of eight streams with different land uses their watersheds (forested and rural areas) in the lower Iguaçu River basin was inventoried, order to evaluate composition species richness. fishes were sampled quarterly from May 2015 February 2016, using electrofishing technique. In total, 4,239 individuals captured, belonging six orders, 11 families 26 species. orders Siluriformes Characiformes, Characidae Trichomycteridae most specious. Of total sampled, 65% endemic basin,...

Human pressures have been intensely modifying freshwater ecosystems worldwide. We assessed the effects of human pressure on habitat diversity and primary productivity to understand consequences fish fauna in 25 tropical subtropical streams two globally important ecoregions: Iguassu Upper Paraná. hypothesized that increased (urbanization agriculture) stream environments, both at local catchment scales, directly decreases diversity. also triggers changes composition structure. evaluated...

Abstract This study explores the interplay between digestive tract traits, food intake, and assimilation in omnivorous tetra fishes ( Psalidodon bifasciatus , P. aff. gymnodontus Bryconamericus ikaa ) from Iguaçu River basin, an ecologically significant region known for high endemism. We hypothesize that variations tracts across species would be associated with differences diet, isotopic composition fish tissues, overall diet assimilation. To test this, we employed stereoscopic light...

During ontogeny, animals often undergo significant shape and size changes, coinciding with ecological shifts. This is evident in parrotfishes (Eupercaria: Labridae), which experience notable shifts during development, transitioning from carnivorous diets as larvae juveniles to herbivorous omnivorous adults, using robust beaks skulls for feeding on coral skeletons other hard substrates. These ontogenetic mirror their evolutionary history, are known have evolved wrasse ancestors. Parallel at...

Abstract Investigating how multiple invasive fish species with similar ecological traits respond to different environmental conditions is crucial understanding their successful invasion and coexistence. Here, we used stomach content analysis stable isotope analyse the effects of water level fluctuation on trophic niche plasticity three dominant co‐occurring tilapia ( Coptodon zillii , Sarotherodon galilaeus Oreochromis niloticus ) in Shanmei Reservoir, southern China. We found that exhibited...

Abstract The drivers of intraspecific niche variation and its effects on species interactions are still unclear, especially in species‐rich Neotropical environments. Here, we investigated how ecological opportunity interspecific competition affect the degree individual trophic specialization population breadth tetra fish. We studied four ecologically similar ( Psalidodon aff. gymnodontus , P . paranae P. bifasciatus Bryconamericus ikaa ) subtropical headwater streams (three sites with two...

The fish fauna from the Lower Iguaçu River and tributaries upstream of Falls, last free-flowing river stretch, were investigated. Twenty five sites in main channel sampled between 2010 2016 using several kinds fishing gear. species categorized according to their size, origin, conservation status. Species richness abundance compared. In total, 87,702 specimens recorded, comprising 76 species, 25 families, 53 genera, eight orders. Characiformes Siluriformes richest orders, representing 92%...

Abstract: The fish fauna of the Pelotas River, in Upper Uruguay ecoregion southern Brazil was inventoried. Samplings were performed quarterly between August 2013 and May 2014 at 14 sites River its tributaries, using gill nets different mesh sizes, sein nets, cast electrofishing. In total, 7,745 specimens recorded, comprising 46 species, belonging to 13 families five orders. Approximately 80% species belonged orders Characiformes Siluriformes, as well Characidae Loricariidae, which included a...

Trophic interactions represent the routes through which energy flows upwards within ecosystems and understanding of such structuring under varying environmental conditions is still challenging. Here we test hypothesis that differences in variables act as filters on composition trophic structure local fish fauna a subtropical mountain river. We predict occur along river continuum. Main parameters have been measured fishes were sampled quarterly between August 2013 May 2014 at six sampling...

Astyanax bifasciatus Garavelo & Sampaio, 2010 was originally described as endemic to the Iguaçu river basin. Between March 2017 and January 2018, specimens of A. were sampled during expeditions headwater streams Piquiri basin, upper Paraná The identification confirmed both by morphological molecular analyses, representing, therefore, first record species outside basin River. In addition, lack structuring in haplotype network confirms that representatives from...