Seasonal variation in fish trophic networks in two clear-water streams in the Central Llanos region, Venezuela
Autor(a) principal: | |
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Data de Publicação: | 2017 |
Outros Autores: | , , , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Neotropical ichthyology (Online) |
Texto Completo: | http://old.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252017000200215 |
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. |
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Seasonal variation in fish trophic networks in two clear-water streams in the Central Llanos region, VenezuelaAquatic ecosystemFlood pulsePredationPredator-prey interactionsTrophic nicheABSTRACT 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.Sociedade Brasileira de Ictiologia2017-01-01info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersiontext/htmlhttp://old.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252017000200215Neotropical Ichthyology v.15 n.2 2017reponame:Neotropical ichthyology (Online)instname:Sociedade Brasileira de Ictiologia (SBI)instacron:SBI10.1590/1982-0224-20160125info:eu-repo/semantics/openAccessPeterson,Christopher C.Keppeler,Friedrich W.Saenz,David E.Bower,Luke M.Winemiller,Kirk O.eng2017-07-06T00:00:00Zoai:scielo:S1679-62252017000200215Revistahttp://www.ufrgs.br/ni/https://old.scielo.br/oai/scielo-oai.php||neoichth@nupelia.uem.br1982-02241679-6225opendoar:2017-07-06T00:00Neotropical ichthyology (Online) - Sociedade Brasileira de Ictiologia (SBI)false |
dc.title.none.fl_str_mv |
Seasonal variation in fish trophic networks in two clear-water streams in the Central Llanos region, Venezuela |
title |
Seasonal variation in fish trophic networks in two clear-water streams in the Central Llanos region, Venezuela |
spellingShingle |
Seasonal variation in fish trophic networks in two clear-water streams in the Central Llanos region, Venezuela Peterson,Christopher C. Aquatic ecosystem Flood pulse Predation Predator-prey interactions Trophic niche |
title_short |
Seasonal variation in fish trophic networks in two clear-water streams in the Central Llanos region, Venezuela |
title_full |
Seasonal variation in fish trophic networks in two clear-water streams in the Central Llanos region, Venezuela |
title_fullStr |
Seasonal variation in fish trophic networks in two clear-water streams in the Central Llanos region, Venezuela |
title_full_unstemmed |
Seasonal variation in fish trophic networks in two clear-water streams in the Central Llanos region, Venezuela |
title_sort |
Seasonal variation in fish trophic networks in two clear-water streams in the Central Llanos region, Venezuela |
author |
Peterson,Christopher C. |
author_facet |
Peterson,Christopher C. Keppeler,Friedrich W. Saenz,David E. Bower,Luke M. Winemiller,Kirk O. |
author_role |
author |
author2 |
Keppeler,Friedrich W. Saenz,David E. Bower,Luke M. Winemiller,Kirk O. |
author2_role |
author author author author |
dc.contributor.author.fl_str_mv |
Peterson,Christopher C. Keppeler,Friedrich W. Saenz,David E. Bower,Luke M. Winemiller,Kirk O. |
dc.subject.por.fl_str_mv |
Aquatic ecosystem Flood pulse Predation Predator-prey interactions Trophic niche |
topic |
Aquatic ecosystem Flood pulse Predation Predator-prey interactions Trophic niche |
description |
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. |
publishDate |
2017 |
dc.date.none.fl_str_mv |
2017-01-01 |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://old.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252017000200215 |
url |
http://old.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252017000200215 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
10.1590/1982-0224-20160125 |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
text/html |
dc.publisher.none.fl_str_mv |
Sociedade Brasileira de Ictiologia |
publisher.none.fl_str_mv |
Sociedade Brasileira de Ictiologia |
dc.source.none.fl_str_mv |
Neotropical Ichthyology v.15 n.2 2017 reponame:Neotropical ichthyology (Online) instname:Sociedade Brasileira de Ictiologia (SBI) instacron:SBI |
instname_str |
Sociedade Brasileira de Ictiologia (SBI) |
instacron_str |
SBI |
institution |
SBI |
reponame_str |
Neotropical ichthyology (Online) |
collection |
Neotropical ichthyology (Online) |
repository.name.fl_str_mv |
Neotropical ichthyology (Online) - Sociedade Brasileira de Ictiologia (SBI) |
repository.mail.fl_str_mv |
||neoichth@nupelia.uem.br |
_version_ |
1752122182607044608 |