Book
Food webs in two neotropical stream systems as revealed by stable isotope ratios
01 Jan 2001
Abstract
Trophic relationships in tropical streams are obscured to some extent by a high degree of omnivory and stable isotopes can be useful in determining the degree of omnivory in such systems. We measured isotope ratios ( delta super(13)C and delta super(15)N) in major trophic levels in three streams of varying trophic complexity that were located at two major neotropical research sites: La Selva Biological Station in Costa Rica and the Luquillo Experimental Forest in Puerto Rico. In all streams, the delta super(15)N values increased with increasing trophic position of the species, as expected. One shrimp species, Macrobrachium, may be more of an omnivore in Costa Rica than in Puerto Rico where it feeds higher in the food web. The two fish species in the Rio Salto, Costa Rica, were also clearly distinguished in their trophic positions by their delta super(15)N values. There was a marked difference in the super(15)N at the base of the food web in two streams in Puerto Rico compared to the one in Costa Rica, which was significantly higher. The Rio Salto in Costa Rica had high super(15)N values for the food base (mean 5.0ppt) compared to the two streams in Puerto Rico (mean 1.7ppt). We concluded that this was because of the larger contribution of remineralized nitrogen to and within the stream in Costa Rica.
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Details
- Title
- Food webs in two neotropical stream systems as revealed by stable isotope ratios
- Creators
- S KilhamC Pringle
- Contributors
- W D Williams (Editor)
- Resource Type
- Book
- Language
- English
- Academic Unit
- [Retired Faculty]
- Identifiers
- 3510540557; 9783510540556; 991019170574704721