The mosaic of habitats of the Seine estuary: Insights from food-web modelling and network analysis

Type Article
Date 2015-09
Language English
Author(s) Tecchio Samuele1, Rius Antonio1, Dauvin Jean-Claude2, Lobry Jeremy3, Lassalle Geraldine3, Morin Jocelyne4, Bacq Nicolas5, Cachera Marie6, Chaalali Aurelie1, 7, Villanueva Ching-MariaORCID8, Niquil Nathalie1
Affiliation(s) 1 : Normandie Univ UNICAEN, UMR BOREA, MNHN, UPMC,CNRS 7208,IRD 207, F-14000 Caen, France.
2 : Normandie Univ UNICAEN, UMR M2C, UCBN, UR,CNRS 6143, F-14000 Caen, France.
3 : IRSTEA, UR EABX Aquat Ecosyst & Global Changes, F-33612 Cestas, France.
4 : IFREMER, F-14520 Port En Bessin, France.
5 : Grp Interet Publ Seine Aval, F-76100 Rouen, France.
6 : IFREMER, Lab Ressources Halieut, F-62321 Boulogne Sur Mer, France.
7 : IFREMER, Fisheries Ecol & Modeling Dept, F-44311 Nantes 3, France.
8 : IFREMER, Lab Biol Halieut, F-29280 Plouzane, France.
Source Ecological Modelling (0304-3800) (Elsevier Science Bv), 2015-09 , Vol. 312 , P. 91-101
DOI 10.1016/j.ecolmodel.2015.05.026
WOS© Times Cited 20
Keyword(s) Trophic network, Estuary, Ecological network analysis, Ecopath with Ecosim, Food web, Ecosystem health indicators
Abstract Ecological network analysis was applied in the Seine estuary ecosystem, northern France, integrating ecological data from the years 1996 to 2002. The Ecopath with Ecosim (EwE) approach was used to model the trophic flows in 6 spatial compartments leading to 6 distinct EwE models: the navigation channel and the two channel flanks in the estuary proper, and 3 marine habitats in the eastern Seine Bay. Each model included 12 consumer groups, 2 primary producers, and one detritus group. Ecological network analysis was performed, including a set of indices, keystoneness, and trophic spectrum analysis to describe the contribution of the 6 habitats to the Seine estuary ecosystem functioning. Results showed that the two habitats with a functioning most related to a stressed state were the northern and central navigation channels, where building works and constant maritime traffic are considered major anthropogenic stressors. The strong top-down control highlighted in the other 4 habitats was not present in the central channel, showing instead (i) a change in keystone roles in the ecosystem towards sediment-based, lower trophic levels, and (ii) a higher system omnivory. The southern channel evidenced the highest system activity (total system throughput), the higher trophic specialisation (low system omnivory), and the lowest indication of stress (low cycling and relative redundancy). Marine habitats showed higher fish biomass proportions and higher transfer efficiencies per trophic levels than the estuarine habitats, with a transition area between the two that presented intermediate ecosystem structure. The modelling of separate habitats permitted disclosing each one's response to the different pressures, based on their a priori knowledge. Network indices, although non-monotonously, responded to these differences and seem a promising operational tool to define the ecological status of transitional water ecosystems.
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Tecchio Samuele, Rius Antonio, Dauvin Jean-Claude, Lobry Jeremy, Lassalle Geraldine, Morin Jocelyne, Bacq Nicolas, Cachera Marie, Chaalali Aurelie, Villanueva Ching-Maria, Niquil Nathalie (2015). The mosaic of habitats of the Seine estuary: Insights from food-web modelling and network analysis. Ecological Modelling, 312, 91-101. Publisher's official version : , Open Access version :