Seasonal variation in fish trophic networks in two clear-water streams in the Central Llanos region, Venezuela
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 Charco...
| Main Authors: | , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Sociedade Brasileira de Ictiologia
2017-07-01
|
| Series: | Neotropical Ichthyology |
| Subjects: | |
| Online Access: | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252017000200215&lng=en&tlng=en |
| _version_ | 1818914975962365952 |
|---|---|
| author | Christopher C. Peterson Friedrich W. Keppeler David E. Saenz Luke M. Bower Kirk O. Winemiller |
| author_facet | Christopher C. Peterson Friedrich W. Keppeler David E. Saenz Luke M. Bower Kirk O. Winemiller |
| author_sort | Christopher C. Peterson |
| collection | DOAJ |
| 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. |
| first_indexed | 2024-12-19T23:54:56Z |
| format | Article |
| id | doaj.art-e68411a888f143a8848c15033fd1d8a3 |
| institution | Directory Open Access Journal |
| issn | 1982-0224 |
| language | English |
| last_indexed | 2024-12-19T23:54:56Z |
| publishDate | 2017-07-01 |
| publisher | Sociedade Brasileira de Ictiologia |
| record_format | Article |
| series | Neotropical Ichthyology |
| spelling | doaj.art-e68411a888f143a8848c15033fd1d8a32022-12-21T20:01:03ZengSociedade Brasileira de IctiologiaNeotropical Ichthyology1982-02242017-07-0115210.1590/1982-0224-20160125S1679-62252017000200215Seasonal variation in fish trophic networks in two clear-water streams in the Central Llanos region, VenezuelaChristopher C. PetersonFriedrich W. KeppelerDavid E. SaenzLuke M. BowerKirk O. WinemillerABSTRACT 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.http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252017000200215&lng=en&tlng=enEcossistema aquáticoInterações predador-presaNicho tróficoPredaçãoPulso de inundação |
| spellingShingle | Christopher C. Peterson Friedrich W. Keppeler David E. Saenz Luke M. Bower Kirk O. Winemiller Seasonal variation in fish trophic networks in two clear-water streams in the Central Llanos region, Venezuela Neotropical Ichthyology Ecossistema aquático Interações predador-presa Nicho trófico Predação Pulso de inundação |
| title | 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_short | 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 |
| topic | Ecossistema aquático Interações predador-presa Nicho trófico Predação Pulso de inundação |
| url | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252017000200215&lng=en&tlng=en |
| work_keys_str_mv | AT christophercpeterson seasonalvariationinfishtrophicnetworksintwoclearwaterstreamsinthecentralllanosregionvenezuela AT friedrichwkeppeler seasonalvariationinfishtrophicnetworksintwoclearwaterstreamsinthecentralllanosregionvenezuela AT davidesaenz seasonalvariationinfishtrophicnetworksintwoclearwaterstreamsinthecentralllanosregionvenezuela AT lukembower seasonalvariationinfishtrophicnetworksintwoclearwaterstreamsinthecentralllanosregionvenezuela AT kirkowinemiller seasonalvariationinfishtrophicnetworksintwoclearwaterstreamsinthecentralllanosregionvenezuela |