A wolf in sheep's clothing: carnivory in dominant sea urchins in the Mediterranean
| Autor: | C Palacín, Javier Romero, Xavier Turon, Owen S. Wangensteen, Mireia Recasens, Alex Garcia-Cisneros |
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| Přispěvatelé: | Universitat de Barcelona |
| Rok vydání: | 2011 |
| Předmět: |
0106 biological sciences
Eriçons de mar Stable isotope analysis Aquatic Science Population biology Arbacia lixula 010603 evolutionary biology 01 natural sciences Actinia schmidti Paracentrotus lividus Benthic communities Mediterranean Sea Marthasterias 14. Life underwater Sea urchins Ecology Evolution Behavior and Systematics Trophic level Isotope analysis Marine biology Ecology biology Mediterrània (Mar) 010604 marine biology & hydrobiology Coralline algae Biologia marina biology.organism_classification 13. Climate action Biologia de poblacions Omnivore Trophic relationships |
| Zdroj: | Dipòsit Digital de la UB Universidad de Barcelona Digital.CSIC. Repositorio Institucional del CSIC instname Recercat. Dipósit de la Recerca de Catalunya |
| Popis: | 12 páginas, 4 figuras, 6 tablas. Arbacia lixula and Paracentrotus lividus are the dominant sea urchins in the Mediterranean sublittoral, where they are key structuring species due to their grazing activity. It has been commonly accepted that competition between both species is minimized by specializing in different algal foods: A. lixula is considered to feed mainly on encrusting coralline algae, while P. lividus prefers fleshy macroalgae. We used stable isotope analysis to test if these species occupy different trophic positions at three western Mediterranean and one Macaronesian locations. Our results unambiguously show that A. lixula always occupies a higher trophic level than P. lividus, with a δ15N comparable in some locations to strict carnivores such as Actinia schmidti or Marthasterias glacialis. A temporal monitoring at one locality showed that this signature of a higher trophic level is consistent throughout the year. These results are incompatible with the current belief of an herbivorous diet for A. lixula and suggest that it must be considered an omnivore tending to carnivory in Mediterranean ecosystems, feeding at least partially on sessile animals such as Cirripedia, Hydrozoa or Bryozoa. A parallel analysis of gut contents showed a predominance of vegetal items in both species, although A. lixula consistently had a higher abundance of animal components than P. lividus. Our results challenge the validity of using gut content observations alone for characterizing the trophic behaviour of omnivorous marine invertebrates that feed on a variety of food sources with different digestibility. This work has been funded by the projects CTM2007-66635, CTM2010-22218 from the Spanish Government, and the project BIOCON 08-187/09 from BBVA Foundation. |
| Databáze: | OpenAIRE |
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