Modelling the distribution of the Ocellated Lizard in France : implications for conservation

The Ocellated Lizard, Timon lepidus (Daudin 1802) occupies the Mediterranean regions of southwestern Europe (Portugal, Spain, France, and the extreme northwest of Italy). Over the last decades, a marked decline in its population has been observed, particularly on the northern edge of its distribution. As a result, it is currently considered a threatened species, especially in France and Italy. In France, a national action plan for its conservation has been put in place. In this study, ecological niche modelling (ENM) was carried out over the entire area of France in order to evaluate the species' potential distribution, more accurately define its ecological niche, guide future surveys, and inform land use planning so this species can be better taken into consideration. The modelling used data representing 2,757 observation points spread over the known range of the species, and 34 ecogeographical variables (climate, topography, and vegetation cover) were evaluated. After removing correlated variables, models were fitted with several combinations of variables using eight species distribution model (SDM) algorithms, and then their performance was assessed using three model accuracy metrics. Iterative trials changing the input variables were used to obtain the best model. The optimized model included nine determining variables. The results indicate the presence of this species is linked primarily to three climate variables: precipitation in the driest month, precipitation seasonality, and mean temperature in the driest quarter. The model was checked by a sample dataset that was not used to fit the model, and this validation dataset represented 25% of the overall field observations. Of the known occurrence locations kept aside to check the results, 94% fell within the presence area predicted by the modelled map with a presence probability greater than 0.7, and 90% fell within the area with a presence probability ranging from 0.8 to 1, which represents a very high predictive value. These results indicate that the models closely matched the observed distribution, suggesting a low impact of either geographical factors (barriers to dispersal), historical factors (dispersal process), or ecological factors (e.g., competition, trophic resources). The overlap between the predicted distribution and protected areas for this species reveals that less than 1% of the potential distribution area is protected by strong regulatory measures (e.g., national parks and natural reserves). The knowledge obtained in this study allows us to recommend some guidelines that would favor the conservation of this species.Peer reviewe

3000 ans de modifications des environnements littoraux à Kition Bamboula (Larnaca, Chypre, Méditerranée Orientale) [3000 years of coastal evolution of Kition Bamboula (Larnaca, Cyprus, Mediterranean sea)]

The Paleo-environmental reconstruction of the coastal sector of Kition Bamboula demonstrates that this area was an open bay that became separated from the Mediterranean sea. The evolution has been basically led by relative sea-level variations, tectonic mobility and variations in sediment supply. Coupled with archeological data, the cores stratigraphy emphasizes six distinct environments of deposition since 3000 years B.P. (A) Around 3000 BP, an open marine embayment is characterized by a calm sedimentation. The influences of external dynamics are mitigated by the presence of a Postdoma reef barrier. This first type of environment was used as a mycenian harbour between XIV-XIIIth centuries BC. (B) Between 2000 BP and 1600 BP, a lagoon is characterized by marine juvenile molluscs dying quickly in this environment that corresponds to a «leaky lagoon». The initial marine embayment was then partially closed by a spit and used as a Phoenician military harbour. (C) After 1600 BP, an hypersaline lagoon with sporadic dessication, formed as the consequence of the almost complete closure of the lagoon which could be due either to tectonic uplift or sedimentary processes. Gypsum was formed by either subaqueous or interstitial crystallisation. Restricted connections with the open sea were discontinuous. Pelagic foraminifera were introduced during occasional marine floodings probably related to storms. (D) A re-opening of the coastal pan converted the sabkha into a brackish lagoon. This lagoon was used by Romans as a port. This re-opening might be linked to relative sea-level rise. (E) Finally, the lagoon was partially closed, transformed in marshland and described by travellers as the ancient harbour. (F) Since British colonization, an artificial filling-up of the coastal plain has transformed the quite steady paludal wetland into an urban complex.Dans le cadre de la fouille archéologique du port de Kition Bamboula à Larnaca, nous avons pu mettre en évidence six phases de modifications littorales depuis 3000 ans. (A) Vers 3000 ans BP, un golfe marin est protégé par des herbiers de posidonies. Il a servi de zone portuaire au Bronze Récent (XIVème et XIIIème siècles avant J.-C). (B) Après 2000 ans BP, l'environnement devient lagunaire. (C) A partir de 1600 ans BP, le milieu correspond à une lagune côtière hypersaline à ennoyage intermittent. Cette ouverture peut s'expliquer par l'obturation d'un grau ou un soulèvement tectonique éventuel du secteur étudié. (D) On assiste ensuite à une réouverture du milieu qui se transforme en lagune en voie de colmatage. (E) Finalement, les marécages côtiers sont bonifiés par l'administration coloniale britannique et le trait de côte est totalement artificialisé, en relation avec la croissance urbaine récente (F).Morhange Christophe, Goiran Jean Philippe, Bourcier Michel, Carbonel Perre, Kabouche Benjamin, Le Campion Joël, Prone André, Pyatt Bryan, Rouchy Jean Marie, Sourisseau Jean Christophe, Yon Marguerite. 3000 ans de modifications des environnements littoraux à Kition Bamboula (Larnaca, Chypre, Méditerranée Orientale) [3000 years of coastal evolution of Kition Bamboula (Larnaca, Cyprus, Mediterranean sea)]. In: Quaternaire, vol. 10, n°2-3, 1999. pp. 133-149