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Does the invasive plant Elymus athericus modify fish diet in tidal salt marshes?

Laffaille, Pascal and Pétillon, Julien and Parlier, Emmanuel and Valéry, Loïc and Ysnel, Frédéric and Radureau, Alain and Feunteun, Eric and Lefeuvre, Jean-Claude Does the invasive plant Elymus athericus modify fish diet in tidal salt marshes? (2005) Estuarine, Coastal and Shelf Science, Vol. 65 (n° 4). pp. 739-746. ISSN 0272-7714

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Official URL: http://dx.doi.org/10.1016/j.ecss.2005.07.023

Abstract

The invasion of Mont-Saint-Michel Bay salt marshes (France) by a grass species (Elymus athericus) has led to important changes in vegetation cover, which is likely to modify the habitat for many invertebrates. Some of them constitute the main food items for several fish species, such as young sea bass (Dicentrarchus labrax) and sand goby (Pomatoschistus minutus), that feed in salt marsh creeks during high tides. As a result, fish nursery functions of salt marshes could be modified by the E. athericus invasion. In order to test this hypothesis, gut contents of the two most abundant fish species (sea bass and sand goby) were compared before and after E. athericus invasion in the same salt marsh creek and using the same methodology. The accessibility and availability of the main food item, the semi-terrestrial amphipod Orchestia gammarella, were estimated and compared between invaded (dominated by E. athericus) and original areas (dominated by Atriplex portulacoides). Gut content analysis showed a significantly greater percentage of fish leaving with empty guts from E. athericus areas than from A. portulacoides areas. The sea bass diet composition study showed a major shift in the relative importance of the main food items: before E. athericus invasion, diets were dominated by the semi-terrestrial species O. gammarella, whereas after the E. athericus invasion they were dominated by a marine mysid Neomysis integer. The same trend was found for sand gobies, with a shift of the main food item from O. gammarella before invasion to the polychaete Hediste diversicolor after invasion. These trophic changes may be explained by the lower accessibility and availability of O. gammarella in invaded communities than in natural ones. The E. athericus invasion, observed throughout northern Europe, is thus likely to disturb trophic function of natural salt marshes for fish. This preliminary study of the E. athericus invasion is also an illustration that invasive species are an urgent problem in conservation biology.

Item Type:Article
Additional Information:Thanks to Elsevier editor. The definitive version is available at http://www.sciencedirect.com/science/article/pii/S0272771405002398
HAL Id:hal-00793408
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:Other partners > Muséum national d'Histoire naturelle (FRANCE)
Other partners > Fish-Pass (FRANCE)
Other partners > Université de Rennes 1 (FRANCE)
Laboratory name:
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Deposited By: Pascal LAFFAILLE
Deposited On:11 Feb 2013 10:49

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