Evaluation of a long-term method to monitor the gecko Euleptes europaea on Grand Rouveau Island (Embiez Archipelago, Var, France).

Les suivis de population constituent un préalable nécessaire à l’évaluation des tendances démographiques des espèces. Ils sont en outre indispensables à une bonne évaluation des actions de conservation engagées en faveur des espèces menacées. Pour cela, il convient de disposer de méthodes robustes, facilement reproductibles dans le temps. L’étude conduite sur l’île de Grand Rouveau a pour objectif de tester une méthode de suivi applicable à une espèce cryptique et menacée : le Phyllodactyle d’Europe Euleptes europaea. La méthode consiste à confectionner des gîtes artificiels attractifs pour l’espèce, permettant un suivi simplifié de la population. Pour cela, deux types de gîtes ont été testés : des briques alvéolées et plusieurs tuiles rondes recouvertes d’un amas de pierre. Les résultats obtenus montrent que le système composé de 3 tuiles superposées se prête bien aux objectifs poursuivis. Il est à la fois aisé à mettre en place, facile à contrôler et peu soumis aux biais temporels (heure du jour), météorologiques ou biais d’observateur. Les gîtes posés en mai 2014 ont été rapidement et durablement colonisés par l’espèce, comme l’indiquent les quatre premières années de suivi. La méthode devrait permettre dans le futur de préciser les exigences écologiques de l’espèce et d’évaluer les actions de génie écologique engagées sur l’île : élimination de la plante exotique envahissante Carpobrotus edulis et du Rat noir Rattus rattus.Population surveys are a prerequisite for evaluating the demographic trends of species. Moreover, they are indispensable for assessing conservation measures implemented to protect threatened species. Accurate surveys require robust methods that can be easily reproduced over time. The aim of this study conducted on Grand Rouveau Island was to test the applicability of a long-term monitoring method to a threatened cryptic and nocturnal species: the European leaf-toed gecko Euleptes europaea. The method consisted of constructing artificial refuges attractive to the species to simplify monitoring of the population. To this end, two types of shelters were tested: one type was constructed from honeycomb brick and the other from curved ceramic roof tiles covered with piles of stones. The results showed that the system consisting of three superimposed tiles was particularly suitable for the desired objectives. It is simple to construct, easy to monitor and little affected by temporal, meteorological or observer bias. The shelters of this type placed in May 2014 were rapidly colonized by the species on a long-term basis, as indicated during the first four years of monitoring. This method could allow future studies to better define the ecological requirements of this species and to assess the success of the ecological engineering actions carried out on the island, which include the elimination of the invasive exotic ice plant Carpobrotus edulis and the black rat Rattus rattus

Characteristics of the yearly feeding activity of the Ocellated Lizard (Timon lepidus) based on faeces collected on Oleron Island (French Atlantic coast)

The pattern of the yearly feeding activity of the Ocellated Lizard population on Oleron Island was studied during two one-year periods by collecting the lizards’ faeces along a transect. Collected faeces (753 in 2002, 646 in 2006) allowed understanding in more detail the quantity of the lizards’ food catch over a yearly cycle. Population feeding activity starts in the second 10-day period of March and ends in the third 10-day period of October. The peak of feeding activity was in May in 2002, and in June - July in 2006. This is explained mainly by the length of the day and the average temperature, and to a much lesser extent by the amount of sunshine or rainfall (calculated by multiple linear regression analysis). Findings were that in spite of the extreme geographical position of the Oleron Island population, the pattern of feeding activity varies little from that observed in the Ocellated Lizard populations in the south of France and central Spain. With some conditions, the faeces-collection study method could be used for long-term population monitoringL'activité alimentaire du Lézard ocellé a été étudiée durant 2 années sur l'île d'Oléron, à partir de teces collectees le long d'un transect. La collecte de 753 teces en 2002 et 646 en 2006 permet de suivre avec précision l'importance des prises alimentaires au cours du cycle annuel. L'activité alimentaire débute dans la deuxième décade de mars et s'achève dans la troisième décade d'octobre, avec un pic d'activité en mai en 2002 et en juin-juillet en 2006. Elle est principalement expliquée par la durée du jour et par la température moyenne ; peu par la pluviosité (régression multiple). Le rythme d'activité alimentaire de cette population diffère peu de celui observé dans les populations du sud de la France et du centre de l'Espagne malgré la position géographique extrême de cette population. Moyennant certaines précautions, cette méthode pourrait être utilisée pour un suivi à long terme de la population

Les invasions biologiques

International audienceCet « article » est la transcription - par Christine Silvy - d'une émission radiophonique de France Culture, La Science et les hommes (Atelier du savoir), préparée et animée par Françoise Breton (désignée par FB). Lancés sur les ondes le 2 avril 1997, les propos des cinq invités et de la productrice sont reportés ici sans réarrangement ni réécriture de fond. Un débat livré en différé (dont les arguments n'ont pas vieilli) auquel on a voulu conserver sa spontanéité et son langage parlé

Increase of the fecundity in Hermann’s Tortoise Testudo hermanni hermanni in insular conditions: an opposite case of the insular syndrome?

Increase of the fecundity in Hermann 's Tortoise Testudo hermanni hermanni in insular conditions: an opposite case of the insular syndrome? - The reproductive parameters of the Hermann's Tortoise Testudo hermanni were studied by radiography in Corsica (Porto-Vecchio -island population-) and in Provence (Maures Massif -mainland population-). The following parameters were measured: number of eggs per clutch, clutch frequency, annual fecundity (eggs produced per female per year) and size of the eggs. There was a significantly higher fecundity in the island area, i.e. more eggs per clutch (4 against 3), a higher clutch frequency (1.9 against 1.4) and a global fecundity of 7.7 eggs/female/year as compared to 4.2 eggs/female/year in the mainland area. This increase in fecundity did not change also after taking into account the size of the females, which were larger in the island area. Indeed, female size does not influence the size of the eggs. The observed increase in fecundity contradicts the theory of the insular syndrome which predicts a decrease in fecundity in insular conditions. This dissension may be the result of the originality of tortoises at the ecophysiological level (long lifetime herbivore species) or may partially depend on distinct local adaptations.The reproductive parameters of the Hermann’s Tortoise Testudo hermanni were studied by radiography in Corsica (Porto-Vecchio –island population–) and in Provence (Maures Massif –mainland population–). The following parameters were measured: number of eggs per clutch, clutch frequency, annual fecundity (eggs produced per female per year) and size of the eggs. There was a signifi cantly higher fecundity in the island area, i.e. more eggs per clutch (4 against 3), a higher clutch frequency (1.9 against 1.4) and a global fecundity of 7.7 eggs/female/year as compared to 4.2 eggs/female/year in the mainland area. This increase in fecundity did not change also after taking into account the size of the females, which were larger in the island area. Indeed, female size does not infl uence the size of the eggs. The observed increase in fecundity contradicts the theory of the insular syndrome which predicts a decrease in fecundity in insular conditions. This dissension may be the result of the originality of tortoises at the ecophysiological level (long lifetime herbivore species) or may partially depend on distinct local adaptation

A long-term monitoring program of the ocellated lizard (Timon lepidus) population on Oléron Island

The Ocellated Lizard Timon lepidus (Sauria ; Lacertidae) has declined throughout most of its range. Today it is difficult to assess the extent of this decline. The Ocellated Lizard population of Oléron Island (Charente- Maritime, France) is the subject of a long-term monitoring study established in 2007. This study is repeated every 3 years to follow the population evolution. The population is confined to a long-shore dune of 140 ha. The monitoring method consists of 70 plots (50 x 50 m) randomly placed within a study area divided into six distinct zones. Three surveys were conducted in the study area over the spring season (April, May and June). Results were analysed with PRESENCE 3.0 (Beta) and R 2.8.1. The Ocellated Lizard has a highly heterogeneous distribution on Oléron Island. The site-occupancy model allows us to conclude that the probability of detecting the species in the plots increases over the field. In 2010, this probability was 0.78 in April and 0.97 in May and June. The estimated proportion of occupied sites was 0.83 in 2010 and 0.76 in 2007. Colonization and local extinction are the consequences of the evolution of available shelters (colonization if this resource increases and extinction if it disappears) and of the coastal erosion (habitat loss). The relative abundance of Ocellated Lizards on the island (modeling with the N-mixture model) can be principally explained by the presence of permanent shelters (used both during winter and the lizards’ active period), including rabbit and rodent burrows and artificial shelters. Rabbits are essential and their maintaining is crucial for the Ocellated Lizard conservation. The Ocellated Lizard population size was estimated to be 1025 individuals (95 % CI: 695-1355) in 2010. This monitoring survey will be replicated in 2013. Results will help us in evaluating and guiding management and conservation measuresLe Lézard ocellé Timon lepidus subit un déclin marqué sur l'ensemble de son aire de répartition. Il est cependant difficile d'évaluer quantitativement ce déclin sans la mise en place de protocoles de suivi valides. Dans ce but, un suivi à long terme a été initié en 2007 sur l'île d'Oléron. Celui-ci a été répété en 2010. La méthodologie retenue s'appuie sur la technique dite de « site occupancy ». Elle consiste à réaliser trois visites d'une heure au cours du printemps sur 70 placettes de suivi de 2500 m2 réparties sur les 140 hectares de dunes occupés par l'espèce. En 2010, la probabilité de détection de l'espèce sur l'ensemble des placettes a été de 0,78 (0,05) pour la première visite puis de 0,97 (0,02) pour les deux suivantes. Le taux d'occupation des placettes a été de 0,76 (0,05) en 2007 et de 0,83 (0,04) en 2010. Les colonisations et extinctions locales du Lézard ocellé sur certaines placettes sont dues à l'évolution de la ressource en gîtes (terriers de lapins pour l'essentiel) et à l'érosion littorale (perte d'habitats favorables). Les gîtes permanents (terriers de lapins, trous de rongeurs et gîtes artificiels) sont les variables environnementales qui expliquent le mieux les abondances du Lézard ocellé. Le Lapin de garenne joue donc un rôle primordial dans le maintien de la population de lézards. L'estimation des effectifs de la population réalisée par la technique de « site occupancy » donne des valeurs proches pour les deux périodes de suivi: 1018 (compris entre 602 et 1355) en 2007 et 1025 individus en 2010 (compris entre 695 et 1355). Une troisième session du suivi sera réalisée en 2013. La méthodologie mise en place semble bien adaptée aux objectifs poursuivis. Elle devrait permettre de mieux orienter les actions de gestion mises en œuvre depuis plusieurs années sur cette population

High Genetic Differentiation Among French Populations of the Orsini's Viper (Vipera ursinii ursinii) Based on Mitochondrial and Microsatellite Data: Implications for Conservation Management

The Orsini's viper (Vipera ursinii) is one of the most threatened snakes in Europe due to its highly fragmented distribution and specific open environment (steppic habitat) requirement. French populations are isolated on top of mountain massifs of the southern Prealps/Alps. Mitochondrial sequences (cytochrome b) and 6 microsatellite loci have been used to estimate the levels of genetic diversity and isolation within and among 11 French fragmented populations (a total of 157 individuals). Eleven cytochrome b haplotypes with a limited divergence were observed (mean divergence between haplotypes: 0.31%). However, we detected considerable genetic differentiation among populations (global FST = 0.76 and 0.26 for mitochondrial and nuclear DNA, respectively). Results indicate that 3 populations possibly went through a bottleneck and 1 population showed low genetic diversity compared with the others. Although a significant isolation by distance was detected for both markers, strong differentiation was also observed between geographically close populations, probably due to the ragged landscape that constitutes a serious barrier to gene flow owing to the limited dispersal capability of the viper. Despite some discrepancies between the 2 markers, 8 Management Units have been identified and should be considered for future management project

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

Decline of a Hermann’s Tortoise (Testudo hermanni hermanni Gmelin, 1789) population in forest. Combined effects of several anthropogenic factors

This study investigates the evolution of a population of Hermann’s tortoises, located on the edge of the massif des Maures, over a period of 30 years through capture–recapture monitoring. It shows a considerable decline of 73 % in the number of adult tortoises between the early 1980s and 1999; then from 1999, the population stabilized at around 100 adult tortoises. The fall in numbers during the first period seems to be linked to several factors. The 22 % increase in forest cover between 1983 and 1995 increased the concentrations of eggs laid in some open areas, making it easier for the species’ natural predators to find them. Mechanized clearance of undergrowth carried out in 1989 and 1994 has undoubtedly reduced the size of the population. The presence of dogs has posed an additional threat (97 % of the adult tortoises have bite marks and 7 % are missing limbs). In addition, the impact of dog bites on the tortoises’ shells has, over time, removed individual markings, thereby distorting survival estimates. The stabilization of numbers over the last decade seems to be due to the discontinuation of certain practices (notably mechanized undergrowth clearance). However, the demographic structure (with almost no juveniles) could soon lead to another decrease in population. This situation seems to be specific to this particular population and cannot be applied generally to all the populations in ProvenceCette étude analyse l'évolution d'une population de Tortue d'Hermann située en marge du massif des Maures sur une période de 30 années, sur la base de suivis par capture―recapture. Elle montre une baisse considérable des effectifs adultes (73 %) entre le début des années 1980 et 1999, puis une stabilisation de la population aux alentours de 100 individus adultes à partir de 1999. Cette chute des effectifs sur la première période semble liée à une addition de facteurs. L'augmentation de 22 % du couvert forestier entre 1983 et 1995 accroît la concentration des pontes sur quelques zones ouvertes, ce qui favorise leur découverte par les prédateurs naturels de l'espèce. Des débroussaillages mécaniques conduits en 1989 et 1994 ont certainement amoindri les effectifs de la population. La pression exercée par les chiens (actuellement 97 % des sujets adultes présentent des traces de crocs et 7 % des amputations de membres) vient ajouter une menace supplémentaire. De plus, les impacts de crocs de chien sur les carapaces de tortues ont provoqué une perte des marques individuelles au cours du temps, biaisant ainsi les estimations de survie. La stabilisation des effectifs depuis une dizaine d'années semble due à l'arrêt de certaines pratiques (débroussaillages mécaniques notamment). En revanche, la structure démographique (quasi absence de juvéniles) laisse craindre un effondrement prochain de la population. Cette situation semble propre à cette population et non généralisable à l'ensemble des populations de la Provence

Cartographie des savoirs locaux et gouvernance territoriale multi-niveaux : regards croisés Nord / Sud

Large information systems used by international organizations and central governments are inadequate to meet local development issues. We show through a series of case studies in Northern and Southern situations diverse interest of using local knowledge through mapping. Technological innovations in the field of geomatics and ICT represent a promising approach to enhance the position of this kind of knowledge alongside conventional expertise. (Résumé d'auteur

Plague Circulation and Population Genetics of the Reservoir Rattus rattus: The Influence of Topographic Relief on the Distribution of the Disease within the Madagascan Focus.

International audienceBACKGROUND: Landscape may affect the distribution of infectious diseases by influencing the population density and dispersal of hosts and vectors. Plague (Yersinia pestis infection) is a highly virulent, re-emerging disease, the ecology of which has been scarcely studied in Africa. Human seroprevalence data for the major plague focus of Madagascar suggest that plague spreads heterogeneously across the landscape as a function of the relief. Plague is primarily a disease of rodents. We therefore investigated the relationship between disease distribution and the population genetic structure of the black rat, Rattus rattus, the main reservoir of plague in Madagascar. METHODOLOGYPRINCIPAL FINDINGS: We conducted a comparative study of plague seroprevalence and genetic structure (15 microsatellite markers) in rat populations from four geographic areas differing in topology, each covering about 150-200 km(2) within the Madagascan plague focus. The seroprevalence levels in the rat populations mimicked those previously reported for humans. As expected, rat populations clearly displayed a more marked genetic structure with increasing relief. However, the relationship between seroprevalence data and genetic structure differs between areas, suggesting that plague distribution is not related everywhere to the effective dispersal of rats. CONCLUSIONSSIGNIFICANCE: Genetic diversity estimates suggested that plague epizootics had only a weak impact on rat population sizes. In the highlands of Madagascar, plague dissemination cannot be accounted for solely by the effective dispersal of the reservoir. Human social activities may also be involved in spreading the disease in rat and human populations