Dynamics and genetics of the European pond turtles (Emys orbicularis) population

Defended on the 20th December 2013

Funding: région Bourgogne (60%), Tour du Valat (40%)

Supervisors: François Bretagnolle (université de Bourgogne), Rémi Wattier (université de Bourgogne), Alain Crivelli (Tour du Valat)

Started in October 2010

Abstract

Dispersal, characterized by the movements of individuals in space leading to gene flows, allows populations to connect. The study of dispersal has become of essential importance to predict the consequences of global changes on the population structures and dynamics. Species with limited dispersal, such as chelonians, are particularly threatened by these phenomena. Our study aimed at analyzing the dispersal of the European pond turtle (Emys orbicularis), in decline in Europe, in a habitats fragmentation context and determining the causes of this behavior through analysis of population dynamics and genetics. Our results show, firstly, that the slow generation time in Emys orbicularis (about 12 years) may slow the genetic erosion by drift. This slow erosion is accentuated with large populations such as Kerkini populations, even with a strong fragmentation. On the other hand, selection would have favored philopatry in females in habitats with few nesting site and deers, because they have the advantage of territoriality. In contrast, the cost of dispersal decreases for males because this behavior allows inbreeding avoidance. The European pond turtles seem very sensitive to intra-specific competition. Indeed, the relaxation of adult density-dependence allows for a significant recruitment of juveniles. This dynamic promotes an unexpected rapid response of the population after a major disturbance, because chelonians are long-lived animals with a late age of first reproduction and very high generation time, therefore, the time of resilience to perturbations is also expected to be high.

Keywords

capture-mark-recapture, conservation, density-dependence, dispersal, dynamics, Emys orbicularis, fragmentation, genetics, metapopulation.

Jury

Roger Pradel, CEFE, Montpellier, France – rapporteur
Olivier Verneau, CEFREM, Perpignan, France – rapporteur
Albert Bertolero, IRTA, Barcelone, Espagne – examinateur
Loïc Bollache, INRA, Dijon, France – président du jury
Alain Crivelli, Tour du Valat, Arles, France – codirecteur
Rémi Wattier, université de Bourgogne, Dijon, France – encadrant

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Dynamics and genetics of the European pond turtles (Emys orbicularis) population

Defended on the 20th December 2013

Funding: région Bourgogne (60%), Tour du Valat (40%)

Supervisors: François Bretagnolle (université de Bourgogne), Rémi Wattier (université de Bourgogne), Alain Crivelli (Tour du Valat)

Started in October 2010

 

Abstract

Dispersal, characterized by the movements of individuals in space leading to gene flows, allows populations to connect. The study of dispersal has become of essential importance to predict the consequences of global changes on the population structures and dynamics. Species with limited dispersal, such as chelonians, are particularly threatened by these phenomena. Our study aimed at analyzing the dispersal of the European pond turtle (Emys orbicularis), in decline in Europe, in a habitats fragmentation context and determining the causes of this behavior through analysis of population dynamics and genetics. Our results show, firstly, that the slow generation time in Emys orbicularis (about 12 years) may slow the genetic erosion by drift. This slow erosion is accentuated with large populations such as Kerkini populations, even with a strong fragmentation. On the other hand, selection would have favored philopatry in females in habitats with few nesting site and deers, because they have the advantage of territoriality. In contrast, the cost of dispersal decreases for males because this behavior allows inbreeding avoidance. The European pond turtles seem very sensitive to intra-specific competition. Indeed, the relaxation of adult density-dependence allows for a significant recruitment of juveniles. This dynamic promotes an unexpected rapid response of the population after a major disturbance, because chelonians are long-lived animals with a late age of first reproduction and very high generation time, therefore, the time of resilience to perturbations is also expected to be high.

 

Keywords

capture-mark-recapture, conservation, density-dependence, dispersal, dynamics, Emys orbicularis, fragmentation, genetics, metapopulation.

 

Jury

Roger Pradel, CEFE, Montpellier, France – rapporteur
Olivier Verneau, CEFREM, Perpignan, France – rapporteur
Albert Bertolero, IRTA, Barcelone, Espagne – examinateur
Loïc Bollache, INRA, Dijon, France – président du jury
Alain Crivelli, Tour du Valat, Arles, France – codirecteur
Rémi Wattier, université de Bourgogne, Dijon, France – encadrant