Cet article a été récemment publié dans la revue Freshwater Biology. Issu des résultats de la thèse de Sébastien Ficheux [1], l’étude se penche sur la question de la dispersion de la Cistude d’Europe en Camargue. Il révèle que seuls les mâles adultes participent au processus de dispersion (environ 3% des mâles par an), tandis que les femelles adultes et les jeunes restent totalement philopatriques. Cette étude a également mis en lumière une légère structuration génétique entre les populations les plus éloignées (>3,5 km), tout en offrant des implications importantes pour la conservation de cette espèce emblématique des milieux aquatiques en Camargue.
Vous pouvez le retrouver sur le portail documentaire de la Tour du Valat [2].
Résumé:
1- Dispersal has major impacts on population dynamics, population genetics and evolution, and also is critical for population management and conservation. Dispersal is frequently sex- and age-specific, but current knowledge is strongly taxonomically biased toward birds and mammals.
2- Here, we provide estimates of dispersal in a threatened freshwater turtle species, the European pond turtle Emys orbicularis. Based on 15 years of capture-mark-recapture (CMR) monitoring and DNA samples from 194 individuals, we quantified both demographic and genetic dispersal between three sites separated by 1.5–3.5 km. We also investigated the effect of age and sex on dispersal.
3- Direct (CMR) and indirect (genetic) approaches provided consistent results, showing that the studied sites are connected with a flow of about one to three dozen migrants per generation. Dispersal was both age- and sex-biased in this species, with frequent dispersal of adult males and a strong philopatry of juveniles (of both sexes) and adult females.
4- The network of canals and marshes allow effective dispersal to occur among the three study sites despite the relatively large distance separating them (≤3.5 km).
5- The strong philopatry of juveniles contrasts with the frequently higher dispersal rate in young birds and mammals and shows the relevance of investigating dispersal in various taxonomic groups. Our results provide useful information for the conservation of European pond turtle populations.
Référence bibliographique : Fay, R., Ficheux, S., Béchet, A., Besnard, A., Crochet, P.-A., Leblois, R., Crivelli, A., Wattier, R., & Olivier, A. (2023). Direct and indirect estimates of dispersal support strong juvenile philopatry and male-biased dispersal in a freshwater turtle species (Emys orbicularis). Freshwater Biology. https://doi.org/10.1111/fwb.14171 [3]