Ecomorphological variations and food supply drive trophic relationships in the fish fauna of a pristine neotropical stream

Baldasso, Mara Cristina; Wolff, Luciano Lazzarini; Neves, Mayara Pereira; Delariva, Rosilene Luciana

doi:10.1007/s10641-019-00871-w

Cited by 24 publications

(20 citation statements)

References 86 publications

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“…Although both species rely largely on terrestrial invertebrates during the wet season, our findings agree with previous studies from streams (Baldasso et al 2019), rivers (Pini et al 2019) and reservoirs (Delariva et al 2013;Mise et al 2013), suggesting higher consumption of terrestrial invertebrates by P. gymnodontus. Leaves and seeds were consumed in considerable proportions by both species (Fig.…”

Section: Discussionsupporting

confidence: 92%

“…In the Iguaçu river basin (Brazil), there are 12 species of the genera Astyanax and Psalidodon (Haluch and Abilhoa 2005;Abilhoa and Duboc 2007;Pavanelli and Oliveira 2009;Baumgartner et al 2012;Ingenito and Duboc 2014); with Psalidodon bifasciatus (Garavello and Sampaio 2010) and Psalidodon gymnodontus (Eigenmann 1911) among the most common and dominant species (Baumgartner et al 2012;Neves et al 2015;Larentis et al 2016;Delariva et al 2018;Baldasso et al 2019). These species were recently relocated to the genus Psalidodon by Terán et al (2020), previously being recognized as Astyanax gymnodontus and Astyanax bifasciatus.…”

Section: Introductionmentioning

confidence: 99%

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Seasonal feeding plasticity can facilitate coexistence of dominant omnivores in Neotropical streams

Neves

Kratina

Delariva

et al. 2021

Rev Fish Biol Fisheries

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Coexistence of ecomorphologically similar species in diverse Neotropical ecosystems has been a focus of long-term debate among ecologists and evolutionary biologists. Such coexistence can be promoted by trophic plasticity and seasonal changes in omnivorous feeding. We combined stomach content and stable isotope analyses to determine how seasonal variation in resource availability influences the consumption and assimilation of resources by two syntopic fish species, Psalidodon aff. gymnodontus and P. bifasciatus, in the Lower Iguaçu basin. We also tested the impact of seasonality on trophic niche breadth and diet overlap of these two dominant omnivores. Seasonal changes in resource availability strongly influenced the consumption and assimilation of resources by the two fish species. Both species exhibited high levels of omnivory, characterized by high diversity of allochthonous resources in the wet season. Terrestrial invertebrates were the main component of diet during this season. However, in the dry season, both species reduced their isotopic niches, indicating diet specialization. High diet overlap was observed in both seasons, but the isotopic niche overlap was smaller in the dry season. Substantial reduction in the isotopic niche of P. bifascistus and a shift toward aquatic invertebrates can facilitate coexistence during this season of resource shortage. Feeding plasticity allows omnivorous fish to adjust their trophic niches according to seasonality, promoting the exploitation of different resources during periods of greater resource diversity. This seasonal variation could be an important mechanism that contributes to the resource partitioning and coexistence of dominant omnivores in Neotropical streams.

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Section: Discussionsupporting

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Seasonal feeding plasticity can facilitate coexistence of dominant omnivores in Neotropical streams

Neves

Kratina

Delariva

et al. 2021

Rev Fish Biol Fisheries

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“…Due to clear ecological (i.e., trophic, behavioral, microhabitat use) and morphological differences between characid and other taxonomic families, we did not consider other species of Siluriformes and Cyprinodontiformes as potential direct interspecific competitors. In addition, we did not observe any predatory species of Characidae species, as well as in previous studies carried out in streams in the study region (Baldasso et al., 2019; Delariva et al., 2018; Neves et al., 2015).…”

Section: Methodssupporting

confidence: 88%

“…In Neotropical streams, several ecologically similar fish species co‐occur and potentially compete for common resources. How these species interact locally has been widely studied in an interspecific perspective; however, ecological studies have rarely taken into account intraspecific variations (Baldasso et al., 2019; Neves et al., 2015; Pini et al., 2019). Among these similar co‐occurring species, small characids (tetra fish) exhibit a striking diversity in morphology and life history across species, but also conspicuous variation within populations (Bonato et al., 2017; Garita‐Alvarado et al., 2018; Silva et al., 2017).…”

Section: Introductionmentioning

confidence: 99%

Seasonality and interspecific competition shape individual niche variation in co‐occurring tetra fish in Neotropical streams

et al. 2020

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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 and interspecific competition affect the degree of individual trophic specialization and the population niche breadth in tetra fish. We studied the four ecologically similar species (Psalidodon aff. gymnodontus, P. aff. paranae, P. bifasciatus, and Bryconamericus ikaa) in subtropical headwater streams (three sites with two co‐occurring species and three sites with only one species). We sampled fish in two contrasting seasons (winter/dry and summer/wet) and quantified their trophic niches using gut content analysis. Psalidodon bifasciatus was the only species distributed over all the sampled streams. We observed seasonal differences in population trophic niche breadth of P. bifasciatus just when this species co‐occurred with P. aff. gymnodontus. These findings confirm the complex nature of the effects of interspecific competition, depending, for instance, on the identity of the competitor. The degree of individual specialization of P. bifasciatus was higher in the winter, and it was not influenced by the presence of another species. Conversely, the other two Psalidodon species studied presented greater individual specialization in the summer, when fish consumed a higher proportion of allochthonous items (terrestrial insects and seeds), and there were no effects only for B. ikaa. Herein, our results suggest that seasonality in food‐resource availability is a major driver of niche variation and it has the potential to play an important role in how these similar tetra species interact and coexist. Abstract in Portuguese is available with online material.

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“…A total of twenty‐eight morphological measurements (Table 1) related directly or indirectly to feeding were made (Baldasso et al, 2019; Boyle & Horn, 2006; Pease et al, 2018; Shuai et al, 2018). All the measurements (to the nearest 0.01 mm) were made on adult fish species using vernier callipers (Mitutoyo 6” AOS Digital Caliper).…”

Section: Methodsmentioning

confidence: 99%

Role of morphology in shaping the feeding niche of fishes inhabiting Eastern Himalayan torrential rivers of West Bengal, India

Podder

Panja

Chaudhuri

et al. 2021

Ecology of Freshwater Fish

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Ecomorphology and trophic ecology are considered important features in comprehending the feeding structure of fish communities. This study assesses the ecomorphological relationships among 45 fish species inhabiting the Eastern Himalayan torrential rivers, Murti and Jaldhaka by identifying morphological and trophic associations highlighted by prey acquisition strategies and the potential phylogenetic convergence among morphological traits. Two approaches (3‐guild and 5‐guild) were employed for evaluating the prediction accuracy of morphology in classifying the guilds. While the former was based on “troph” (dietary index) values, the later focussed on diet dissimilarity matrix. In terms of phylogenetic relatedness, traits such as caudal peduncle aspect ratio and mouth protrusion showed prominent phylogenetic signal which suggested their evolutionary convergence in certain groups. Subsequent modelling suggested that while linear discriminant model showed morphological traits to have higher accuracy (91.1%) in classifying the three guilds as compared to five guilds (72.31%), redundancy model (explaining 85.26% constrained variance) revealed a morphological association with specific prey type selection. Additionally, linear models showed substantial variation (93.72%) in the dietary index being addressed by the 5‐guild classification as compared to the 3‐guild (79.72%). Results suggested that in terms of prey composition or selectivity, the 5‐guild model was more suited in representing the feeding structure while the morphological traits reflected a broader scheme of classification (3‐guild model). Hence, this provides an ecological insight into the different modes of resource utilisation by the coexisting species which are being expressed in their differentiating morphologies, with certain traits being phylogenetically conserved within specific feeding groups.

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Ecomorphological variations and food supply drive trophic relationships in the fish fauna of a pristine neotropical stream

Cited by 24 publications

References 86 publications

Seasonal feeding plasticity can facilitate coexistence of dominant omnivores in Neotropical streams

Seasonal feeding plasticity can facilitate coexistence of dominant omnivores in Neotropical streams

Seasonality and interspecific competition shape individual niche variation in co‐occurring tetra fish in Neotropical streams

Role of morphology in shaping the feeding niche of fishes inhabiting Eastern Himalayan torrential rivers of West Bengal, India

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