1. Stable isotope niche convergence in coexisting native and non-native salmonids across age classes
- Author
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Cucherousset, Julien, Zavorka, Libor, Ponsard, Sergine, Cereghino, Regis, and Santoul, Frederic
- Subjects
Fishes ,Trout ,Earth sciences - Abstract
Niche divergence resulting from coevolution is commonly believed to favour coexistence among competing species; however, recent investigations have demonstrated that an unexpected niche convergence can occur when native and non- native species coexist. Yet, our understanding of the ontogenetic characteristics of this niche convergence remains limited. In the present study, we quantified the stable isotope niche of native brown trout (Salmo trutta) in allopatry and sympatry with non-native brook trout (Salvelinusfontinalis) across four age classes. Our results demonstrated that brown trout displayed a stable isotope niche closer to brook trout in sympatry than in allopatry, which was likely driven by an increased consumption of terrestrial invertebrates by sympatric brown trout. Stable isotope niche overlap was the strongest for young-of-the- year individuals and the intensity of overlap between sympatric native brown trout and non-native brook trout decreased during ontogeny. These findings indicate that niche convergence between the species occur at the earliest age class of the native species and are maintained across ontogeny. La divergence de niche est une mecanisme qui favorise la coexistence des especes mais des travaux recents ont demontre qu'une convergence de niche pouvait se produire lorsque des especes natives et non-natives coexistaient. Ace jour, notre connaissance de la mise en place de cette convergence au cours de l'ontogenie reste neanmoins limitee. Dans cette etude, nous avons quantifie la niche isotopique de quatre classes d'age d'une espece native, la truite commune (Salmo trutta), vivant en allopatrie et en sympatrie avec une espece non-native, l'omble de fontaine (Salvelinusfontinalis). Nos resultats demontrent que la truite commune presente une niche isotopique plus semblable a celle des ombles de fontaine en sympatrie par rapport a sa niche isotopique en allopatrie et que cela est probablement cause par une plus forte consommation d'invertebres terrestres par les truites communes en sympatrie. Le chevauchement des niches isotopiques est le plus important pour les juveniles de l'annee, et l'intensite du chevauchement entre truites communes et ombles de fontaine en sympatrie diminue au cours de l'ontogenese. Ces resultats indiquent que la convergence de niches se produit des la toute premiere classe d'age de l'espece native et se poursuit durant toute la vie des individus., Introduction Biological invasions can provide new insights into our understanding of species coexistence because co-evolutionary history is lacking in novel communities resulting from human introductions of non-native species (Cadotte et [...]
- Published
- 2020
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