Damming in the Madeira River modifies the food spectrum of piscivorous and affects their resource partitioning

Autor: Alessandra Pasian Lonardoni, Cristhiana Paula Röpke, Taís Melo, Gislene Torrente-Vilara
Jazyk: angličtina
Rok vydání: 2021
Předmět:
Zdroj: Neotropical Ichthyology, Vol 19, Iss 3 (2021)
Druh dokumentu: article
ISSN: 1982-0224
DOI: 10.1590/1982-0224-2021-0087
Popis: Abstract Phylogenetic proximity suggests some degree of diet similarity among species. Usually, studies of diet show that species coexistence is allowed by partitioning food resources. We evaluate how visually oriented piscivorous fishes (Characiformes) share prey before and after building the Santo Antônio Hydroelectric Power Plant (HPP) in the Madeira River (Brazil), the largest muddy-water tributary of the Amazon River. Piscivorous species (Acestrorhynchus falcirostris, Acestrorhynchus heterolepis, Hydrolycus scomberoides, and Rhaphiodon vulpinus) were sampled under pristine (pre-HPP) and disturbed (post-HPP) environmental conditions. We analyzed species abundance and stomach contents for stomach fullness and prey composition to check variations between congeneric and non-congeneric species. The percent volume of prey taxa was normalized by stomach fullness and grouped into the taxonomic family level to determine diet, niche breadth, and overlap. Only R. vulpinus abundance increased in post-HPP. There was no significant variation in niche breadth between the periods, while niche overlap decreased in congeneric and non-congeneric species. Our results indicate that river impoundment affected piscivorous fishes in distinct ways and modified their resource partitioning. Therefore, evaluate interspecific interactions is a required tool to understand how fishes respond to river damming.
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