Species from all major taxonomic groups are experiencing major population declines due to human-driven pressures, including habitat destruction, climate change, pollution, overexploitation, and invasive species. Islands are especially vulnerable, as they host many endemic species with small populations and limited genetic diversity, making them highly sensitive to environmental disturbance. To protect endangered species, conservation actions often focus on the most vulnerable populations through protected areas, population reinforcement, translocations, and invasive species control. Among these strategies, the eradication or control of invasive alien species (IAS) is widespread on islands. Success rates have improved in recent years, even on remote or technically challenging islands. However, removing invasive small mammalian predators remains difficult, as eradication outcomes depend on many interacting factors: technical feasibility, cost, ecological impact, social acceptability, risk of reinvasion, and species behaviour. Trapping efficiency depends heavily on ecological knowledge such as animal density, home range, and movement patterns. Behavioural traits such as trap avoidance can reduce effectiveness, especially in mustelids and other carnivores. In inhabited or poorly isolated areas, reinvasion from surrounding regions can also compromise success, particularly where short dispersal corridors exist, such as land connections. This context is especially relevant for the White-breasted Thrasher ( Ramphocynclus brachyurus ), a bird strictly endemic to the Caravelle peninsula in Martinique, a French Caribbean island. The species occupies about 1,000 hectares and is listed as endangered. One of its main threats is predation by the small Indian mongoose ( Urva auropunctata ), an introduced predator known to prey on eggs, chicks, and probably fledglings and adults. To assess whether mongoose extirpation could be considered a realistic management option, we evaluated different scenarii of control design on simulated mongoose populations by combining field data on the movement of female mongooses and litterature on their population dynamics. We captured and equipped 19 individuals from dry forest patches of the peninsula with GPS devices during the dry season, when control measures are most efficient for reducing population growth. Of these, 16 produced sufficient data to estimate their movement parameters and home ranges. These results were then mobilised to simulate the movements of a hypothetical population of females across the peninsula, to evaluate how trap spacing, trapping duration, and individual behavior regarding traps could influence eradication success. The costs associated with the different successful trapping designs were calculated to determine optimal strategies regarding cost-benefit ratio.

Confronté à un (ou plusieurs) prédateur mammalien introduit, le gestionnaire d’un territoire insulaire est amené à définir une stratégie de lutte, en associant à sa réflexion des scientifiques et des opérateurs extérieurs compétents. Cette stratégie a pour objectif final le retour à une biodiversité et à un fonctionnement de l’écosystème proches de ceux qui précédaient l’arrivée de l’espèce introduite, en éliminant les effets néfastes qu’elle exerce sur les populations ou communautés d’espèces fragiles et rares. Elle s’appuie généralement sur un objectif opérationnel d’éradication, c’est-à-dire d’élimination de tous les individus de la population insulaire concernée. Nous détaillons ici l’historique des opérations d’éradication menées principalement envers des rongeurs, Rat surmulot Rattus norvegicus (Berkenhout, 1769) et Rat noir Rattus rattus (Linnaeus, 1758), et de façon plus limitée des carnivores, Furet Mustela furo Linnaeus, 1758 et Vison d’Amérique Neogale vison (Schreber, 1777), dans des îles de la façade atlantique française appartenant à six départements (Loire-Atlantique, Morbihan, Finistère, Côtes-d’Armor, Ille-et-Vilaine et Manche). Ces opérations ont débuté en 1994. Une ancienne opération, menée au début des années 1950 avec un poison violent sur l’île Rouzic (les Sept Îles), est également rappelée. Après un descriptif de la méthodologie préconisée pour l’éradication, nous détaillons les deux protocoles appliqués successivement dans le cas des rats. Le premier, de 1994 à 2010, était fondé sur l’utilisation d’une lutte mécanique (pièges non vulnérants) suivie d’une lutte chimique (rodenticides anticoagulants). Le second, mis en pratique depuis 2016, recourt uniquement à la lutte chimique. Nous passons en revue les aspects techniques (expertise écologique ; choix de la densité des postes, du type de piège et de la molécule toxique ; nécropsies et prélèvements de matériel biologique ; calcul d’indices d’abondance), ainsi que les normes réglementaires. Alors que 95 % des rats piégés à l’issue de l’opération (premier protocole) le sont en moyenne après onze jours, 95 % des appâts consommés (second protocole) le sont en moyenne après 17 jours. Le résultat des opérations d’éradication sur les îles françaises de la façade atlantique, appliquant l’un ou l’autre des deux protocoles, est de 13 succès sur 18 opérations aux résultats connus (avec une seule opération pour le Rat noir). Une analyse approfondie des échecs montre que les opérations d’éradication du Rat surmulot utilisant l’un ou l’autre des deux protocoles ont toujours été couronnées de succès, sauf dans deux cas. D’une part, lorsque la possibilité d’une recolonisation par l’estran n’avait pas été suffisamment prise en compte, c’est-à-dire si les mesures de biosécurité consécutives au piégeage et/ou à l’appâtage étaient insuffisantes. D’autre part, lorsque les conditions d’application des protocoles n’avaient pas pu être pleinement respectées, en raison de problèmes logistiques et/ou de perturbations anthropiques inévitables. Bien que nous considérions que les deux protocoles ont permis d’obtenir des résultats très satisfaisants, nous préconisons à l’avenir le second, utilisant uniquement la lutte chimique, pour des raisons purement logistiques.

The Reeves’ muntjac Muntiacus reevesi is an ungulate native to China and Taiwan that has been released into the wild in several continental European countries and the United Kingdom. We present recent records of the species in mainland France. We also investigated the dispersal rate and density of the established population in the Centre-Val de Loire region. The number of observations of M. reevesi was low in the period 2008–2016, increased sharply until 2019 and then decreased until 2023. From a comparison between the distribution in 2008–2012 and 2013–2017, the dispersal rate was estimated at an average of 3.2 km/year, and 7.6 km/year between 2013–2017 and 2018–2023. Based on a camera trap protocol, the population density was assumed to be very low in forested areas but estimated with a lack of robustness due to a single observation. Further efforts must be made to better assess the risk of an increase in the wild population of Reeves’ muntjac in the Centre-Val de Loire region. To prevent potential impacts, rapid control measures can be put in place in the large area (10,800 km2) where muntjacs are now rapidly spreading.

The eco-epidemiology of tick-borne diseases hinges on the abundance and distribution of hosts that sustain tick populations and the pathogens they carry. Research into the role of bird species in the feeding of Ixodes ricinus ticks, the primary tick species of veterinary and public health importance in Europe, remains scarce. This study endeavors to bridge these knowledge gaps by (i) assessing the density of feeding ticks (DFT) within a bird community to pinpoint species making substantial contributions, and (ii) exploring interannual variations in DFT over an extended timeline. Furthermore, we investigate whether variations in individual tick burden (TB) were more closely associated with the characteristics of bird species or interannual variations affecting the density of questing tick, using interannual TB variation as a surrogate. To fulfill these aims, we conducted a 13-year longitudinal study monitoring I. ricinus ticks feeding on a bird community in a periurban forest in France, covering breeding periods from 2007 to 2019. Within this community, we identified seven principal bird species significantly contributing to I. ricinus tick feeding: the Common Blackbird (Turdus merula), the Song Thrush (Turdus philomelos), the European Robin (Erithacus rubecula), the Dunnock (Prunella modularis), the Eurasian Blackcap (Sylvia atricapilla), the Great Tit (Parus major), and the Common Nightingale (Luscinia megarhynchos). Our results show that the bird community's contribution to tick feeding remained relatively consistent from year-to-year, though certain years displayed higher or lower DFT values related to the average over the study period. Moreover, five out the seven major species accounted for 80 % to 95 % of DFT annually. Consequently, we emphasized the need to broaden the scope of future research on bird contributions to tick population dynamics beyond merely thrushes (Turdidae species), to encompass a more diverse range of species, particularly those common birds that engage in ground foraging activities. Furthermore, variations in individual tick burden were predominantly influenced by the characteristics of bird species rather than by interannual variability in infestation rates. This finding suggests a significant role for species-specific traits in determining tick exposure and susceptibility. In conclusion, our study offers new insights into the medium-term dynamics of tick-bird ecological systems, underscoring the need for future study of tick populations and their interactions with vertebrate hosts to improve our understanding of tick-borne disease circulation.

Domestic cats (Felis catus), one of the most popular pets, are widespread worldwide. This medium-sized carnivore has well-known negative effects on biodiversity, but there is still a need to better understand the approximate causes of their predation. Based on a citizen science project, we assessed the role of spatiotemporal (i.e., latitude, longitude, and seasons), climatic (i.e., rainfall), anthropogenic (i.e., human footprint, HFI), and individual (i.e., sex and age) variables on the number of preys returned home by cats in metropolitan France. Over the 5048 cats monitored between 2015 and 2022, prey from 12 different classes (n = 36,568) were returned home: 68% mammals, 21% birds, and 8% squamates. Shrews brought home by cats peaked during summer, while rodents were recorded during summer-autumn. Birds brought home by cats peaked in spring-summer and in autumn, and lizards peaked in spring and in late summer. Lower HFI was associated with more voles and mice brought home, and the opposite trend was observed for lizards and birds. Younger cats were more prone to bring home shrews, birds, and reptiles. Although environmental factors play a minor role in prey brought home by cats, some geographical characteristics of prey species distribution partly explains the hunting behaviour of cats.

Abstract At the landscape level, intensification of agriculture, fragmentation, and destruction of natural habitats are major causes of biodiversity loss that can be mitigated at small spatial scales. However, the complex relationships between human activities, landscapes, and biodiversity are poorly known. Yet, this knowledge could help private stakeholders managing seminatural areas to play a positive role in biodiversity conservation. We investigated how water‐abstraction sites could sustain species diversity in vascular‐plant communities and two taxonomic groups of insect communities in a fragmented agricultural landscape. Landscape‐scale variables (connectivity indices and surrounding levels of herbicide use), as well as site‐specific variables (soil type for vascular plants, floral availability for Rhopalocera, and low herbaceous cover for Orthoptera), were correlated to structural and functional metrics of species community diversity for these taxonomic groups, measured on 35 industrial sites in the Ile‐de‐France region in 2018–2019. Rhopalocera and Orthoptera consisted essentially of species with a high degree of dispersal and low specialization, able to reach the habitat patches of the fragmented landscape of the study area. Sandy soil harbored more diverse vascular‐plant communities. Plant diversity was correlated to a greater abundance of Rhopalocera and a lower richness of Orthoptera. Increasing landscape connectivity was related to higher abundance of plants and Rhopalocera, and a higher evenness index for Orthoptera communities. Higher levels of herbicide use were related to a decrease in the biodiversity of plants and Rhopalocera abundance. High levels of herbicide favored high‐dispersal generalist plants, while high levels of connectivity favored low‐dispersal plants. Specialist Orthoptera species were associated with low herbaceous cover and connectivity. Water‐abstraction sites are valuable seminatural habitats for biodiversity. Changing intensive agricultural practices in surrounding areas would better contribute to conserving and restoring biodiversity on these sites.

Understanding the habitat-related hunting behavior of house cats Felis catus is needed to evaluate their potential predatory effect on areas they actively visit within their home range. As part of a citizen science program, 30 neutered cats from 25 households were equipped by their owners during, on average, 2 consecutive days per month between January and November 2016 with a GPS programmed to acquire fixes at 1 to 5 min intervals. Nine cats were located in rural environments, 9 in suburban landscapes, and 12 in urban habitats. For 16 of these cats, preys brought home were recorded daily. Using the recursive distribution movement-based kernel density estimator, rural cats had the largest mean home range area (3.5 +/- 0.3 ha), followed by suburban (2.1 +/- 0.2 ha) and city cats (1.4 +/- 0.1 ha). Moreover, suburban cats enlarged their frequently visited areas in April-June, which corresponded to a peak in small bird preys brought home. Our results suggest that a more diversified landscape may drive domestic cats to increase their home range by benefiting from higher numbers of exploitable areas.

Although black (Rattus rattus) and brown (Rattus norvegicus) rats are among the most widespread synanthropic wild rodents, there is a surprising scarcity of knowledge about their ecology in the urban ecosystem. In particular, relatively few studies have investigated their helminth species diversity in such habitat. We followed the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) guideline to synthesize the existing published literature regarding the helminth fauna of urban rats in developed countries (North America, Europe, Australia, New Zealand and Japan). We aimed at describing the species diversity and richness of urban rat helminths, the species prevalence and associations, the methods of investigation, the pathological changes observed in the hosts, the risk factors of infection and the public health significance of rat-borne helminthiases. Twenty-three scientific papers published between 1946 and 2019 were reviewed, half of them were conducted in Europe. Twenty-five helminth species and eight genera were described from the liver, digestive tract, lungs and muscles of urban rats. The most commonly reported parasite was Calodium hepaticum. Prevalence and risk factors of helminth infection in urban rats varied greatly between studies. Observed pathological findings in the rat host were generally minor, except for C. hepaticum. Several rat helminths can parasitize humans and are therefore of public health significance. The lack of references to identification keys and the rare use of molecular tools for species confirmation represent the main limitation of these studies. Knowledge gap on this topic and the needs for future research are discussed.

Forests constitute one of the most important feeding and foraging habitats for bats. Because bat populations are declining, most likely due to habitat loss or fragmentation, it is imperative to understand the issues concerned with timber exploitation on bat conservation. We investigated the foraging activity of edge- and open-space foragers in relation to stand and vegetation structure, characteristics that are commonly affected by forestry. Acoustic surveys, culminating to 713 point count sites were undertaken covering 46 different forest massifs across mainland France over 6 years. We used generalized linear mixed models to analyse the activity of ten species: 6 edge-habitat and 4 open-habitat foragers. Pipistrellus pipistrellus was the most detected edge-habitat forager, while Nyctalus leisleri was the most recorded of the open-habitat foragers. Eptesicus serotinus and P. pipistrellus responded positively to heterogeneous vertical vegetation volume. In addition, P. kuhlii and P. nathusii responded negatively to tree basal area. Barbastella barbastellus, Hypsugo savii, and P. nathusii were associated with either ground deadwood and/or logging tracks and minor-traffic roads, confirming the importance of edge space. Finally, B. barbastellus, E. serotinus, and P. nathusii were positively linked to the presence of tree microhabitats. This study demonstrates that bat use in forests is complex and multifaceted. Maintaining ground deadwood and heterogeneity of vegetation, at the forest plot scale, should ensure the ecological functioning of exploited forest systems and the conservation of edge- and open-habitat foraging bats.

The house mouse (Mus musculus domesticus), as a successful invasive species worldwide, has to forage a variety of resources. Subantarctic mice display among the most notable diet shift from the usual omnivorous-granivorous diet, relying on a larger proportion of terrestrial animal prey. In agreement, a recent study of their mandible morphology evidenced an evolution of their mandible shape to optimize incisor biting and hence seize preys. Here, the incisors themselves are the focus of a morphometric analysis combined with a 3D study of their internal structure, aiming at a comparison between subantarctic populations (Guillou island, Kerguelen archipelago) with a range of western European continental, commensal mice. The predatory foraging behavior of Guillou mice was indeed associated with a sharper bevel of the lower incisor, which appears as an efficient morphology for piercing prey. The incisor of these mice also displays a reduced pulp cavity, suggesting slower eruption counterbalancing a reduced abrasion on such soft food material. The dynamics of the ever-growing incisor may thus allow adaptive incisor sculpting and participate to the success of mice in foraging diverse resources.

Eurasian red squirrels (Sciurus vulgaris) in the British Isles are the most recently discovered animal reservoir for the leprosy bacteria Mycobacterium leprae and Mycobacterium lepromatosis. Initial data suggest that prevalence of leprosy infection is variable and often low in different squirrel populations. Nothing is known about the presence of leprosy bacilli in other wild squirrel species despite two others (Siberian chipmunk [Tamias sibiricus], and Thirteen-lined ground squirrel [Ictidomys tridecemlineatus]) having been reported to be susceptible to experimental infection with M. leprae. Rats, a food-source in some countries where human leprosy occurs, have been suggested as potential reservoirs for leprosy bacilli, but no evidence supporting this hypothesis is currently available. We screened 301 squirrel samples covering four species [96 Eurasian red squirrels, 67 Eastern gray squirrels (Sciurus carolinensis), 35 Siberian chipmunks, and 103 Pallas's squirrels (Callosciurus erythraeus)] from Europe and 72 Mexican white-throated woodrats (Neotoma albigula) for the presence of M. leprae and M. lepromatosis using validated PCR protocols. No DNA from leprosy bacilli was detected in any of the samples tested. Given our sample-size, the pathogen should have been detected if the prevalence and/or bacillary load in the populations investigated were similar to those found for British red squirrels.

Introduced Siberian chipmunks Eutamias sibiricus have been reported to be important reservoirs for human Lyme disease, as they may host high numbers of hard ticks carrying Borrelia spp. and other pathogens. In the present study, we assessed the prevalence of Borrelia spp. and other pathogenic bacteria in ectoparasite arthropod species infesting Siberian chipmunks and coexisting native small rodents. Small rodents were trapped with Sherman traps in Veneto (NE Italy), where the largest Italian populations of chipmunks occur. A total of 14 individual ticks were found on 223 rodents, with 6 more ticks obtained from stored dead chipmunks from the same study area. Ectoparasites were screened for pathogens by molecular analyses including species-specific PCR amplifications. Rickettsia monacensis, Borrelia lusitaniae, and Anaplasma platys were present in the parasites of both native rodents and introduced chipmunks. The present findings suggest a role for the invasive species E. sibiricus in the maintenance of the Ixodes ricinus life cycle, which may result in the modification of the transmission dynamics of tick-borne pathogens. Moreover, the presence of Rickettsia in urban populations of chipmunks may represent a serious risk for human health and should be investigated further.

Reproduction costs depend on the general life-history strategies employed by organisms for resource acquisition, the decision rules on resource allocation, and the resource availability. Although the predictability of resource availability is expected to influence the breeding strategy, the relationship between predictability and strategy has rarely been investigated at the population level. One reason is that, while the resource availability is commonly variable in space and time, their predictability is generally assumed constant. Here, we addressed the temporal variation of the breeding strategy and its associated survival cost in a hibernating population of Tamias sibiricus, in which food resources vary in their availability between years and in their predictability within years. Based on 11 years of mark–recapture data, we used multi-event modelling to investigate seasonal variations in reproduction costs of female chipmunks that breed twice a year (spring and summer). In summer, during which a large variety and quantity of resources is available (income breeding strategy), the proportion of breeding females was consistent across years and reproduction yielded no mortality cost. In contrast, in spring, the proportion of breeding females was positively correlated with the amount of resources available for hibernation (partial capital breeding strategy). Spring reproduction yielded no immediate cost, but induced a delayed mortality cost over the next winter if future unknown conditions were unfavorable. Our findings highlight complex temporal reproductive patterns in a short-lived species: not only does the modality of resource acquisition vary among seasons, but also the decision rule to breed and its associated cost.

Convergent evolution in similar environments constitutes strong evidence of adaptive evolution. Transported with people around the world, house mice colonized even remote areas, such as Sub-Antarctic islands. There, they returned to a feral way of life, shifting towards a diet enriched in terrestrial macroinvertebrates. Here, we test the hypothesis that this triggered convergent evolution of the mandible, a morphological character involved in food consumption. Mandible shape from four Sub-Antarctic islands was compared to phylogeny, tracing the history of colonization, and climatic conditions. Mandible shape was primarily influenced by phylogenetic history, thus discarding the hypothesis of convergent evolution. The biomechanical properties of the jaw were then investigated. Incisor in-lever and temporalis out-lever suggested an increase in the velocity of incisor biting, in agreement with observations on various carnivorous and insectivorous rodents. The mechanical advantage related to incisor biting also revealed an increased functional performance in Sub-Antarctic populations, and appears to be an adaptation to catch prey more efficiently. The amount of change involved was larger than expected for a plastic response, suggesting microevolutionary processes were evolved. This study thus denotes some degree of adaptive convergent evolution related to changes in habitat-related changes in dietary items in Sub-Antarctic mice, but only regarding simple, functionally relevant aspects of mandible morphology.

The crossing of host species barriers, through the spreading populations of introduced pet animals that become established in the wild, sets the stage for zoonotic pathogen (re)emergence. A literature review on pathogens that are hosted by the ring-necked parakeet (Psittacula krameri), a worldwide introduced pet, highlighted local infections of captive birds by chlamydial agents with high sanitary risk for human health in its introduced range. We searched for these pathogens through cloacal swabs collected from 85 individuals in an invasive population established in the suburban areas of Paris (Ile-de-France) from 5 localities during the winter seasons between 2011 and 2014. Based on quantitative PCR analysis, Chlamydiaceae shedding was detected at too low levels for species identification in 5 birds, but 1 parakeet (found dead) was positive for Chlamydiaceae typed as Chlamydia avium. The only known hosts recorded for C. avium in Europe are feral pigeons (Columba livia) and captive psittacines. This result raises the question of the sanitary risks associated with new pathogen transmission from exotic pets released in the wild, which could locally affect birds and potentially people who feed birds.

In March 2013, we discovered a population of skinks on Île Tintamarre located northeast of Saint-Martin.All individuals observed in 2013 and 2014 were found in a network of dry stone walls.Genetic and morphological analyses unambiguously show that this population belongs to Spondylurus powelli, which also lives on Anguilla and Saint-Barthélemy, and not to S. martinae, the species of adjacent Saint-Martin.This unexpected pattern of distribution is similar to that of at least one other species of squamate reptile and further supports the distinction of these two recently described species of skinks.The population size is estimated at only 40-50 adult individuals.Threats are specified and we recommend necessary measures for the conservation of this population.

Brown rats are one of the most widespread urban species worldwide. Despite the nuisances they induce and their potential role as a zoonotic reservoir, knowledge on urban rat populations remains scarce. The main purpose of this study was to characterize an urban brown rat population from Chanteraines park (Hauts-de-Seine, France), with regards to haematology, population genetics, immunogenic diversity, resistance to anticoagulant rodenticides, and community of parasites. Haematological parameters were measured. Population genetics was investigated using 13 unlinked microsatellite loci. Immunogenic diversity was assessed for Mhc-Drb. Frequency of the Y139F mutation (conferring resistance to rodenticides) and two linked microsatellites were studied, concurrently with the presence of anticoagulant residues in the liver. Combination of microscopy and molecular methods were used to investigate the occurrence of 25 parasites. Statistical approaches were used to explore multiple parasite relationships and model parasite occurrence. Eighty-six rats were caught. The first haematological data for a wild urban R. norvegicus population was reported. Genetic results suggested high genetic diversity and connectivity between Chanteraines rats and surrounding population(s). We found a high prevalence (55.8%) of the mutation Y139F and presence of rodenticide residues in 47.7% of the sampled individuals. The parasite species richness was high (16). Seven potential zoonotic pathogens were identified, together with a surprisingly high diversity of Leptospira species (4). Chanteraines rat population is not closed, allowing gene flow and making eradication programs challenging, particularly because rodenticide resistance is highly prevalent. Parasitological results showed that co-infection is more a rule than an exception. Furthermore, the presence of several potential zoonotic pathogens, of which four Leptospira species, in this urban rat population raised its role in the maintenance and spread of these pathogens. Our findings should stimulate future discussions about the development of a long-term rat-control management program in Chanteraines urban park.