This internship is part of the national action plan (PNA [1-4]) for the endemic Corsican snail Tyrrhenaria ceratina, a species currently represented by the only relict and threatened population of Campo dell’Oro (Ajaccio region). This PNA aims to promote actions that favour (i) the in situ protection of this unique population whose range is less than two hectares, (ii) the restoration of its habitat, (iii) the reinforcement of the natural population via the translocation of populations to suitable recipient sites.
The proposed landscape genetics approach is a follow-up to the first pioneering genetic study carried out by Camus (2021) [5]. It is based on the signature that environmental and/or demographic changes can leave on the diversity and genetic structure of the metapopulation. The empirical data collected, whether molecular (genotypes, sequences) or environmental (abiotic factors, landscape metrics), will aim to:
– refine the structure of the metapopulation evolving into three distinct genetic groups;
– infer the demographic and phylogeographic history of the metapopulation;
– highlight the underlying mechanisms (evolutionary forces) responsible for the observed genetic divergences;
– identify the environmental variables shaping the dynamics of the metapopulation and promoting gene exchange between the three identified genetic groups. Metrics describing the landscape attributes that are significant for the species will be used to estimate the influence of the permeability of the matrix on the movement of individuals. Structural (migration corridor) and functional (gene flow) connectivity will be compared to assess anthropogenic effects via habitat fragmentation on the Campo dell’Oro metapopulation. This step will make it possible to trace the corridors required for the maintenance/recovery of the metapopulation. It will also allow us to define more precisely the ecological (fundamental) niche of the species, a key information for selecting suitable translocation sites.
Methodology. A sample of approximately 250 individuals (mucus) previously collected in 5 sites of Campo dell’Oro will be analysed using sequences (mitochondrial and nuclear genes) and multilocus microsatellite genotypes (15 loci). DNA extraction and PCRs will be performed in Amiens while sequencing and genotyping will be carried out in Rennes. The functional connectivity and genetic structure of the populations will be investigated by means of classical exploratory and Bayesian analysis methods. The relationship between landscape structure and genetic structure will be assessed using correlative and graph theory approaches.
The internship includes the collection of empirical data, genetic and landscape genetic data analyses, and internship report writing.

[1] Plan National d’Action
[2] Bouchet P., Ripken R. & Recorbet B., 1997. Redécouverte de l’escargot de Corse Helix ceratina au bord de l’extinction. Revue d’Ecologie (La Terre et la Vie), 52: 97-111.
[3] Charrier M., Chevalier L., Paradis G. & Recorbet B., 2005. Field observations on spatial distribution and diet in the terrestrial snail Tyrrhenaria ceratina, an endemic species from Corsica. Notiziario S.I.M., Supplemento al Bollettino Malacologico, 23 (5-8): 8.
[4] Cucherat X., 2019. Mission d’assistance pour le monitoring de l’hélix de corse (Helix ceratina). Arion.idé/CEL Corse. Gondecourt. 29 pp + 5 annexes.
[5]. Camus L., 2021. Intégration de la génétique dans la conservation et la gestion de l’escargot endémique de Corse Equipe de recherche Ecologie et Dynamique des Systèmes Anthropisés Tyrrehanaria ceratina. Rapport de stage de master 2 Ecologie Evolution Génomique, Univ. Clzude Bernard Lyon.

Required study level: We seek a highly motivated and curious candidate. Strong interest in molecular biology, population genetics, landscape ecology, evolution and biostatistics are recommended, meaning that a good background in those domains is desired, but not mandatory. Those skills will be developed during the internship.

– Supervisor(s):
Annie GUILLER1 (PU):
Michel DELAUGERRE2 (Chargé de Mission) :
Jonathan LENOIR1 (CR) CNRS:

– Institute: 1 EDYSAN UMR CNRS 7058, Université Picardie Jules Verne ; 2 Conservatoire du littoral, Délégation Corse ; DREAL de Corse.

The student will be hosted at the research unit EDYSAN (Ecologie et Dynamique des Systèmes Anthropisés, UMR 7058 CNRS – UPJV), 33 rue Saint Leu, 80000 Amiens, France,

Duration: 6 months; starting date (flexible): from February 1, 2022
Salary: traineeship grant (600/month)

Applications (letter, CV and 2 contacts for references) should be sent to Michel DELAUGERRE, Annie GUILLER and Jonathan LENOIR before the 15th of January 2021.

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