Effects of invasive seaweeds on feeding preference

Authors: Fiona Tomas Antonio Box Jorge Terrados

Publish Date: 2010/11/30

Volume: 13, Issue: 7, Pages: 1559-1570

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Abstract

The consequences of invasive species on ecosystem processes and ecological interactions remain poorly understood Predator–prey interactions are fundamental in shaping species evolution and community structure and can be strongly modified by species introductions To fully understand the ecological effects of invasive species on trophic linkages it is important to characterize novel interactions between native predators and exotic prey and to identify the impacts of invasive species on the performance of native predators Although seaweed invasions are a growing global concern our understanding of invasive algae—herbivore interactions is still very limited We used a series of feeding experiments between a native herbivore and four invasive algae in the Mediterranean Sea to examine the potential of native sea urchins to consume invasive seaweeds and the impacts of invasive seaweed on herbivore performance We found that three of the four invasive species examined are avoided by native herbivores and that feeding behaviour in sea urchins is not driven by plant nutritional quality On the other hand Caulerpa racemosa is readily consumed by sea urchins but may escape enemy control by reducing their performance Recognizing the negative impacts of C racemosa on herbivore performance has highlighted an enemy escape mechanism that contributes to explaining how this widespread invasive alga which is preferred and consumed by herbivores is not eradicated by grazing in the field Furthermore given the ecological and economic importance of sea urchins negative impacts of invasive seaweeds on their performance could have dramatic effects on ecosystem function and services and should be accounted for in sea urchin population management strategiesThe authors are indebted to R Gradel and the “Palma Aquàrium” staff for providing facilities and invaluable assistance with the experiments We would also like to thank E Ballesteros A Ceballos N Comalada E Infantes FJ Medina A Sureda and S Deudero and her students for help in the field and the laboratory as well as P Fernandez from the “Serveis Científico Tècnics” University of Barcelona for assistance with C/N analyses Financial support was provided by Grant CTM200501434/MAR from the Spanish Ministry of Science and Innovation FT was funded by Juan de la Cierva Postdoctoral Fellowship

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