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Using an individual-based model to inform estuary management in the Baie de Somme, France

  • Sarah E.A. Le V. dit Durell (a1), Richard A. Stillman (a1), Patrick Triplet (a2), Michel Desprez (a3), Cédric Fagot (a4), Nicolas Loquet (a3), François Sueur (a4) and John D. Goss-Custard (a1)...

Conservation managers need to be able to assess and prioritize issues that may affect their target habitats and species. In the Baie de Somme, France, conservation issues affecting overwintering shorebirds include hunting pressure, cockle fishing, recreational disturbance, Spartina encroachment, and changing sediment levels. We used an individual-based model to predict the effect of these issues on the survival of three shorebird species: dunlin Calidris alpina, oystercatcher Haematopus ostralegus and curlew Numenius arquata. In the model, removing hunting from the mudflats in the eastern part of the estuary had the greatest positive effect on shorebird survival. Oystercatcher survival decreased markedly when stocks of large cockles were reduced to <250 m-2 or numbers of fishermen per day were doubled. Short-term disturbance events, such as walkers, had more effect on shorebird survival than long-term events, such as fishermen. Dunlin, as a protected species, were able to feed outside the Réserve Naturelle and were unaffected by disturbance within the Réserve. Oystercatcher survival decreased when the number of disturbance events within the Réserve exceeded one h-1, and curlew survival when disturbance events exceeded six h-1. Spartina encroachment caused dunlin survival to decline steadily as feeding habitat was lost. Dunlin were also the species most affected by changes in sediment levels, likely to occur through either sedimentation or sea level rise.

Corresponding author
§Centre for Ecology and Hydrology Dorset, Winfrith Technology Centre, Dorchester, Dorset, DT2 8ZD, UK. E-mail
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Atkinson P.W., Clark N.A., Bell M.C., Dare P.J., Clark J.A. & Ireland P.L. (2003) Changes in commercially fished shellfish stocks and shorebird populations in the Wash, England. Biological Conservation, 114, 127141.
Caldow R.W.G., Beadman H.A., McGrorty S., Stillman R.A., Goss-Custard J.D., Durell S.E.A. Le V. dit et al. . (2004) A behavior-based modeling approach to reducing shorebird-shellfish conflicts. Ecological Applications, 14, 14111427.
Cramp S. & Simmons K.E.L. (eds) (1983) Handbook of the Birds of Europe, the Middle East and North Africa. The Birds of the Western Palearctic, Vol. III. Oxford University Press, Oxford, UK.
Cresswell W. & Whitfield D.P. (1994) The effects of raptor predation on wintering wader populations at the Tyninghame estuary, southeast Scotland. Ibis, 136, 223232.
Davidson N.C., Lafoley D. d'A., Doody J.P., Way L.S., Gordon J., Key R. et al. . (1991) Nature Conservation and Estuaries in Britain. Nature Conservancy Council, Peterborough, UK.
Desprez M. (1995) Etude sur le fonctionnement et la productivité biologique de l'écosysteme Baie de Somme. GEMEL, St Valery, France.
Durell S.E.A. Le V. dit, McGrorty S., West A.D., Clarke R.T., Goss-Custard J.D. & Stillman R.A. (2005a) A strategy for baseline monitoring of estuary Special Protection Areas. Biological Conservation, 121, 289301.
Durell S.E.A. Le V. dit, Stillman R.A., Caldow R.W.G, McGrorty S., West A.D. & Humphreys J. (2006) Modelling the effect of environmental change on shorebirds: a case study on Poole Harbour, UK. Biological Conservation, 131, 459473.
Durell S.E.A. Le V. dit, Stillman R.A., Triplet P., Aulert C., Ono dit Biot D., Bouchet A. et al. . (2005b) Modelling the efficacy of proposed mitigation areas for shorebirds: a case study on the Seine estuary, France. Biological Conservation, 123, 6777.
Goss-Custard J.D. & Moser M.E. (1988) Rates of change in the number of dunlin, Calidris alpina, wintering in British estuaries in relation to the spread of Spartina anglica. Journal of Applied Ecology 25, 95109.
Goss-Custard J.D., Stillman R.A., West A.D., Caldow R.W.G., Triplet P., Durell S.E.A. Le V. dit et al. . (2004) When enough is not enough: shorebirds and shellfishing. Proceedings of the Royal Society of London, Series B: Biological Sciences, 271, 233237.
Goss-Custard J.D., Triplet P., Sueur F. & West A.D. (2006a) Critical thresholds of disturbance by people and raptors in foraging wading birds. Biological Conservation 127, 8897.
Goss-Custard J.D., West A.D., Yates M.G., Caldow R.W.G., Stillman R.A., Castilla J. et al. . (2006b) Intake rates and the functional response in shorebirds (Charadriiformes) eating macro-invertebrates. Biology Reviews, 81, 129.
Gray A.J. & Benham P.E.M. (eds) (1990) Spartina anglica - A Research Review. HMSO, London, UK.
Grimm V. & Railsback S.F. (2005) Individual-based Modelling and Ecology. Princeton University Press, Princeton, USA.
Horwood J.W. & Goss-Custard J.D. (1977) Predation by the oystercatcher, Haematopus ostralegus L. in relation to the cockle Cerastoderma edule L. fishery in the Burry Inlet, South Wales. Journal of Applied Ecology, 14, 139158.
McClusky D.S., Desprez M., Elkaim B. & Duhamel S. (1994) The inner estuary of the Baie de Somme. Estuarine Coastal and Shelf Science, 38, 313318.
Prater A.J. (1981) Estuary Birds of Britain and Ireland. Poyser, Calton, UK.
Sogreah/EDF (1995) Etude sédimentologique de la Baie de Somme. Synthèse des données naturelles, analyse des mécanismes d'évolution sédimentaire et paramètres à retenir pour la modèle réduit. Conseil General de la Somme, DDE de la Somme, France.
Stillman R.A., Goss-Custard J.D., West A.D., Durell S.E.A. Le V. dit, McGrorty S., Caldow R.W.G. et al. . (2001) Predicting shorebird mortality and population size under different regimes of shellfishery management. Journal of Applied Ecology, 38, 857868.
Stillman R.A., West A.D., Durell S.E.A. Le V. dit, Caldow R.W.G., McGrorty S., Yates M.G. et al. . (2005a) Estuary Special Protection Areas - Establishing Baseline Targets for Shorebirds. Final Report. English Nature, Peterborough, UK.
Stillman R.A., West A.D., Goss-Custard J.D., McGrorty S., Frost N.J., Morrisey D.J. et al. . (2005b) Predicting site quality for shorebird communities: a case study on the Humber estuary, UK. Marine Ecology Progress Series, 305, 213217.
Stroud D.A., Mudge G.P. & Pienkowski M.W. (1990) Protecting Internationally Important Bird Sites. Nature Conservancy Council, Peterborough, UK.
Sueur F. & Triplet P. (1999) Les Oiseaux de la Baie de Somme. SMACOPI/GOP/CDL/RNBS, Abbeville, France.
Triplet P., Bacquet S., Lengignon A., Oget E. & Fagot C. (1999) Effets de dérangements sur l'Huîtrier-pie (Haematopus ostralegus) en Baie de Somme. Gibier Faune Sauvage, 15, 4564.
Triplet P., Méquin N., Prévost A., Erlinger D. & Sueur F. (2003) Rythme d'activité diurne de l'Huîtrier-pie Haematopus ostralegus, du Courlis cendré Numenius arquata et du Bécasseau variable Calidris alpina en Baie de Somme. Alauda, 71, 459468.
Triplet P. & Rousseau S. (2001) Plan de gestion de la Réserve Naturelle de la Baie de Somme 2001-2005. SMACOPI, Abbeville, France.
West A.D., Goss-Custard J.D., Durell S.E.A. Le V. dit & Stillman R.A. (2005) Maintaining estuary quality for shorebirds: towards simple guidelines. Biological Conservation, 123, 211224.
West A.D., Goss-Custard J.D., McGrorty S., Stillman R.A., Durell S.E.A. Le V. dit, Stewart B. et al. . (2003) The Burry shellfishery and oystercatchers: using a behaviour-based model to advise on shellfishery management policy. Marine Ecology Progress Series, 248, 279292.
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