Data/hora: 11/06/2024 02:09:24

Provedor de dados: | 83
País: | Brazil
Título: | Seasonal variation in fish trophic networks in two clear-water streams in the Central Llanos region, Venezuela
Autores: | Peterson,Christopher C.; Keppeler,Friedrich W.; Saenz,David E.; Bower,Luke M.; Winemiller,Kirk O.
Data: | 2017-01-01
Ano: | 2017
Palavras-chave: | Aquatic ecosystem; Flood pulse; Predation; Predator-prey interactions; Trophic niche.
Resumo: | ABSTRACT Food webs are not static entities; consumer resource interactions vary in both time and space, which complicates depiction and comparisons of food web structures. We estimated fish assemblage structure and diets in two clear-water streams in the Venezuelan Llanos region (Charcote and Charcotico) and constructed trophic networks (sub-webs defined by fishes as the principal consumers) during four periods of the annual flood pulse. As stream conditions changed from high-water to low-water, we hypothesized that: 1) the piscivore-non-piscivore ratio would increase; 2) dietary diversity would decrease; 3) interspecific dietary overlap would decline; 4) fewer allochthonous food items would be consumed; and 5) food-web connectance would increase. The piscivore-non-piscivore abundance ratio was higher in both streams during the low-water period. Dietary diversity declined as water levels dropped and availability of aquatic habitats and resources declined, but interspecific dietary overlap was not lower. Contrary to our hypothesis, average interspecific dietary overlap increased at Charcote as the dry season progressed, even though dietary overlap among species was significantly lower than expected by chance. We did not find strong support for our hypotheses regarding seasonal patterns of consumption of allochthonous resources and food web connectance, both of which revealed little seasonal variation.
Tipo: | Info:eu-repo/semantics/article
Idioma: | Inglês
Identificador: | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252017000200215
Editor: | Sociedade Brasileira de Ictiologia
Relação: | 10.1590/1982-0224-20160125
Formato: | text/html
Fonte: | Neotropical Ichthyology  v.15 n.2 2017
Fonte: | info:eu-repo/semantics/openAccess