Effects of restocking for hunting purpose: the Mallard case

Transcription

1 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

2 Population dynamics Emigration Immigration Mortality Natality

3 Case of exploited populations Emigration Immigration Natural mortality + Hunting mortality Natality Management practices to compensate exploitation

4 Harvest regulations Artificial feeding Restocking Predator control Habitat management

5 Restocking Immigration Emigration Restocking Natural mortality + Hunting mortality Natality

6 Galliforms Ungulates Anseriforms Lagomorphs

7 >3 M captive mallards released annually Portugal Great Britain Spain > France Denmark Germany Sweden Italy? Finland Latvia? Czech Republic Hungary Morocco? vs 4.5 M breeding pairs

8 Fate of one released mallard Producers Sold at one day old

9 Fate of one released mallard Producers Sold at one day old Local game breeders 7 weeks in captivity

10 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

11 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

12 Contents 1. Demography Contribution of released mallards to population 2. Threats of restocking captive mallards Genetics Pathogens

13 Releases Breeding May June July April Aug Post release Mortality March Sept Feb Oct Hunting Jan Dec Nov Natural Mortality

14 Methods Ringing of mallards before release Camargue, Brenne, Sweden, Finland

15 Survival Low annual survival independently to hunting pressure

16 Depends on baiting, small gizzard, low body condition Champagnon et al. 2012, EJWR

17 53% of birds shot and reported in Brenne Champagnon et al. 2016, Ibis

18 Proportion of released mallards In Brenne in the wild at breeding mallards released ~ 38% of population with captive origin in February In Camargue mallards released ~ 25% of population with captive origin in February

19 Evidence of breeding Female (code FNR) with 15 chicks on April Released in July 2009.

20 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

21 Contribution to wild population Group Age Reproductive Values Wild 1A 0.32 Wild +1A 0.44 Released 1A 0.03 Released +1A 0.22

22 Effect of a change in harvest rate Population very sensitive to change in harvest rate of wild individuals

23 Index Increase of local hunting bags 2.5 Mallard Hunting Bag - Camargue Mondain-Monval, com. pers.

24 Index Increase in local hunting bags & increase in numbers of mallards counted 2.5 Mallard Hunting Bag & Aerial Count Survey- Camargue Suggest harvest was supported mainly by released mallards

25 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.

26 2- Consequences for wild population Genetics Pathogens

27 27

28 Axe 2 Discriminate captive / wild Captive Museum Axe 1

29 Soderquist et al., unpub

30 Transmission of pathogens to wild population? 30

31 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= Circulation of Influenza virus Vittecoq et al. 2012, PlosOne

32 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

33 Recommendation Goal: Limiting gene flow No improve of captive strain Monitoring at European scale 500 km 300 mi Daniel Dalet Released Wild

34 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

35 Controversial practice Necessary debate / framework for this practice Economics interest Game breeders Managers of private hunting estates

36 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

37 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: 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: 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: Čížková, D., V. Javůrková, J. Champagnon, and J. Kreisinger Duck s not dead: Does restocking with captive bred individuals affect the genetic integrity of wild mallard (Anas platyrhynchos) population? Biological Conservation 152: Vittecoq, M., V. Grandhomme, J. Champagnon, M. Guillemain, B. Crescenzo-Chaigne, F. Renaud, F. Thomas, M. Gauthier-Clerc, and S. van der Werf High Influenza A Virus Infection Rates in Mallards Bred for Hunting in the Camargue, South of France. PLoS ONE 7:e Champagnon, J., P.-A. Crochet, J. Kreisinger, D. Čížková, M. Gauthier-Clerc, G. Massez, P. Söderquist, T. Albrecht, and M. Guillemain Assessing the genetic impact of massive restocking on wild mallard. Animal Conservation 16:

38 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 Behav Ecol Champagnon 2011, PhD thesis Soderquist et al. 2013, EJWR