Effects of restocking for hunting purpose: the Mallard case IUGB 2017 Waterbird population management Jocelyn CHAMPAGNON Pär SÖDERQUIST Johan ELMBERG Jean-Dominique LEBRETON Matthieu GUILLEMAIN
Population dynamics Emigration Immigration Mortality Natality
Case of exploited populations Emigration Immigration Natural mortality + Hunting mortality Natality Management practices to compensate exploitation
Harvest regulations Artificial feeding Restocking Predator control Habitat management
Restocking Immigration Emigration Restocking Natural mortality + Hunting mortality Natality
Galliforms Ungulates Anseriforms Lagomorphs
>3 M captive mallards released annually Portugal 100 000 Great Britain 500 000 Spain > 100 000 France 1 400 000 Denmark 500 000 Germany 100 000 Sweden 200 000 Italy? Finland 10 000 Latvia? Czech Republic 250 000 Hungary 100 000 Morocco? vs 4.5 M breeding pairs
Fate of one released mallard Producers Sold at one day old
Fate of one released mallard Producers Sold at one day old Local game breeders 7 weeks in captivity
Fate of one released mallard Producers Sold at one day old Local game breeders 7 weeks in captivity Hunting managers Released into the wild Artificial feeding
Fate of one released mallard Producers Sold at one day old Local game breeders 7 weeks in captivity Hunting managers Released into the wild Artificial feeding Hunters Harvested
Contents 1. Demography Contribution of released mallards to population 2. Threats of restocking captive mallards Genetics Pathogens
Releases Breeding May June July April Aug Post release Mortality March Sept Feb Oct Hunting Jan Dec Nov Natural Mortality
Methods Ringing of mallards before release Camargue, Brenne, Sweden, Finland
Survival Low annual survival independently to hunting pressure
Depends on baiting, small gizzard, low body condition Champagnon et al. 2012, EJWR
53% of birds shot and reported in Brenne Champagnon et al. 2016, Ibis
Proportion of released mallards In Brenne in the wild at breeding 30 000 mallards released ~ 38% of population with captive origin in February In Camargue 50 000 mallards released ~ 25% of population with captive origin in February
Evidence of breeding Female (code FNR) with 15 chicks on April 2010. Released in July 2009.
Simulation on Camargue data Effect of increase or decrease of hunting harvest on wild individuals? released individuals? Many approximations CONTEXT DEMOGRAPHY CONSEQUENCES Champagnon et al. 2016, DISCUSSION Ornis fennica
Contribution to wild population Group Age Reproductive Values Wild 1A 0.32 Wild +1A 0.44 Released 1A 0.03 Released +1A 0.22
Effect of a change in harvest rate Population very sensitive to change in harvest rate of wild individuals
Index Increase of local hunting bags 2.5 Mallard Hunting Bag - Camargue 2 1.5 1 0.5 0 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 Mondain-Monval, com. pers.
Index Increase in local hunting bags & increase in numbers of mallards counted 2.5 Mallard Hunting Bag & Aerial Count Survey- Camargue 2 1.5 1 0.5 0 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 Suggest harvest was supported mainly by released mallards
Consistent with genetic study High proportion of released mallards in hunting bags Hunting Estates n=41 Nature reserve n=39 CAPTIVE WILD Champagnon et al. 2013, Anim. Conserv.
2- Consequences for wild population Genetics Pathogens
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Axe 2 Discriminate captive / wild Captive Museum 0.8 0.6 0.4 0.2 0-1 -0.5 0 0.5 1 1.5 2-0.2-0.4-0.6-0.8-1 Axe 1
Soderquist et al., unpub
Transmission of pathogens to wild population? 30
Amplification role 2009 Elevage 1; N=222 Low Pathogenic Avian Influenza H10N7 Secreting Elevage 1; N=99 Not Infected Elevage 2; N=100 Elevage 3; N=100 Elevage 4; N=100 2010 Circulation of Influenza virus Vittecoq et al. 2012, PlosOne
Schematic representation of mallard population Released Wild Low survival / reproduction Harvested Few in protected areas Constant survival since 70s Less harvested during hunting Use of protected areas Low contribution of released birds to demography Limited introgression
Recommendation Goal: Limiting gene flow No improve of captive strain Monitoring at European scale 500 km 300 mi Daniel Dalet Released Wild
Potential adverse effect on biodiversity Releases often practiced as an easy way to obtain game for harvest vs. Cost intensive management of wetlands to attract wild birds Adverse impact of restocking
Controversial practice Necessary debate / framework for this practice Economics interest Game breeders Managers of private hunting estates
Acknowledgements Grants: ONCFS, Tour du Valat, Ecole doctorale SIBAGHE Collaborators: Michel Gauthier-Clerc, Jean-Baptiste Mouronval, François Cavallo, Pierre-André Crochet, Olivier Devineau, Pierre Legagneux, Marion Vittecoq, Karin Folkesson, Dasa Ciskova, Jakub Kreisinger, Guillaume Souchay, Pierre Legagneux, William Sutherland, Isabelle Olivieri, Jean-Michel Gaillard. Help with analyses: Olivier Gimenez, Roger Pradel, Rémi Choquet Marais du Vigueirat nature reserve Hunting estate managers Museum and Private collectors Mallard breeding farms managers Trainees and all those that participate in ringing, DNA sampling, nasal saddles resightings, advices Thanks for your attention
References Champagnon, J., J. Elmberg, M. Guillemain, M. Gauthier-Clerc, and J.-D. Lebreton. 2012a. Conspecifics can be aliens too: A review of effects of restocking practices in vertebrates. Journal for Nature Conservation 20:231 241. Champagnon, J., M. Guillemain, J. Elmberg, G. Massez, F. Cavallo, and M. Gauthier-Clerc. 2012b. Low survival after release into the wild: assessing the burden of captivity on Mallard physiology and behaviour. European Journal of Wildlife Research 58:255 267. Champagnon, J., M. Guillemain, J.-Y. Mondain-Monval, G. Souchay, P. Legagneux, V. Bretagnolle, L. Van Ingen, F. Bourguemestre, and J.-D. Lebreton. 2016a. Contribution of released captive-bred Mallards to the dynamics of the natural population. Ornis Fennica 93:3 11. Champagnon, J., P. Legagneux, G. Souchay, P. Inchausti, V. Bretagnolle, F. Bourguemestre, L. Van Ingen, and M. Guillemain. 2016b. Robust estimation of survival and contribution of captivebred Mallards Anas platyrhynchos to a wild population in a large-scale release programme. Ibis 158:343 352. Čížková, D., V. Javůrková, J. Champagnon, and J. Kreisinger. 2012. Duck s not dead: Does restocking with captive bred individuals affect the genetic integrity of wild mallard (Anas platyrhynchos) population? Biological Conservation 152:231 240. Vittecoq, M., V. Grandhomme, J. Champagnon, M. Guillemain, B. Crescenzo-Chaigne, F. Renaud, F. Thomas, M. Gauthier-Clerc, and S. van der Werf. 2012. High Influenza A Virus Infection Rates in Mallards Bred for Hunting in the Camargue, South of France. PLoS ONE 7:e43974. Champagnon, J., P.-A. Crochet, J. Kreisinger, D. Čížková, M. Gauthier-Clerc, G. Massez, P. Söderquist, T. Albrecht, and M. Guillemain. 2013. Assessing the genetic impact of massive restocking on wild mallard. Animal Conservation 16:295 305.
Low dispersal Sweden: 523 km (n=138) Finland: 157 km (n=17) Brenne: 0.7 km (n=316 / 3733) Camargue: 0.6 km (n = 861 / 5085) Legagneux et al. 2009. Behav Ecol Champagnon 2011, PhD thesis Soderquist et al. 2013, EJWR