Les articles de Carole Leray

Nationwide monitoring of seabirds reveals species- and site-specific legacy PFAS contamination in French coastal areas

Fri, 26 Jun 2026 10:30:17

de Prescillia Lemesle, Alice Carravieri, Gauthier Poiriez, Romain Batard, Aurélie Blanck, Coraline Bichet, Gilles Faggio, Jérôme Fort, Fabrice Gallien, William Jouanneau, et al.
In Environment International, (en ligne) (June, 2026), 110386
En ligne : www.sciencedirect.com[...]

Per- and poly-fluoroalkyl substances (hereafter PFAS) are widespread and persistent compounds that pose a threat to human and wildlife health. Wildlife monitoring is essential to understand the extent of PFAS contamination and its ecological drivers. Seabirds are good bioindicators of PFAS contamination of the marine environment, yet some areas including the French coastlines, remain poorly covered. Here, we quantified 11 legacy PFAS in the plasma of 9 seabird species (n = 340 chicks) from 30 sites along the French Atlantic and Mediterranean coasts. Linear perfluorooctanesulfonic acid was by far the most abundant PFAS. Oceanic piscivorous species (Northern gannets Morus bassanus, black-legged kittiwakes, Rissa tridactyla and Scopoli’s shearwaters Calonectris diomedea) had the highest PFAS concentrations compared to Larus sp. gulls, and shags Gulosus aristotelis. Overall, Mediterranean seabirds had lower perfluoroalkyl sulfonic acid and higher perfluoroalkyl carboxylic acid concentrations compared to Atlantic seabirds. At a finer spatial scale, chicks sampled near estuaries had a slightly higher PFAS burden, suggesting local river inputs. This first large-scale survey of PFAS in French seabirds reveals substantial heterogeneity in PFAS contamination across French coastal environments. Future work should address the sources of this PFAS contamination and quantify its toxicological consequences, given that sampled chicks may be at risk based on previous avian studies reporting PFAS-related health effects.

Yellow legged gulls (Larus michahellis): the bridge between human and environmental carbapenemase-producing Enterobacteriaceae?

Fri, 10 Apr 2026 15:31:57

de Guilhem Conquet, Karen D. McCoy, Marion Vittecoq, Carole Leray, Charly Souc, Marie Noëlle Didelot, Chrislène Laurens, Lokman Galal, Julio A. Benavides, Sylvain Godreuil, et al.
In Science of The Total Environment, 1029 (May, 2026), 181695
En ligne : www.sciencedirect.com[...]

Wildlife is frequently reported as a host of antimicrobial resistant bacteria (AMR), often reflecting anthropogenic contamination. Among them, carbapenemase-producing Enterobacteriaceae (CPE) are one of the most worrying for human health. This study investigated the carriage of CPE in yellow-legged gull chicks (Larus michahellis) from a breeding colony of southern France, where CPE have already been detected, and compared these bacterial strains with isolates from humans hospitalized in Montpellier University Hospital, France. Cloacal swabs from 112 chicks revealed a high CPE carriage rate (12 isolates carried by 10 gulls; 8.9%). Detected species included Escherichia coli (n = 3), Citrobacter portucalensis (n = 1) and members of Enterobacter cloacae complex (n = 8). Whole-genome sequencing revealed that 8/12 isolates produced IMI-type carbapenemases (IMI-4 and NMC-A) inserted within EcloIMEX integrative elements, and 4/12 produced OXA-48 located in IncL plasmids. Human and avian CPE isolates did not have common sequences types, although they harbored identical resistance structures (EcloIMEX-1). Some OXA-48-producing E. coli isolates belonged to high-risk human-associated genotypes (ST10, ST648), confirming the potential AMR transmission to gulls via anthropic activities. Conversely, the predominance of IMI-type carbapenemases, typically associated with aquatic environments and rare in clinical settings, suggests that gulls may also carry multidrug resistant bacteria of environmental origin. Positioned at the interface between aquatic ecosystems and human-impacted areas, gulls could contribute to the dissemination of these pathogens beyond their primary reservoirs. These findings highlight the need to integrate wildlife into One Health surveillance frameworks, not only as indicators of anthropogenic AMR but also as potential sentinels of emerging resistance threats.

Detection of a Merbecovirus with potential ACE2 usage in France

Tue, 5 May 2026 09:56:18

de Océane Rieu, Stéphane Descorps-Declère, Anaïs Dufau, Jordan Meliani, Lionel Brazier, Marion Vittecoq, Carole Leray, Anthony Olivier, Illich Mombo, Frederic Thomas, et al.
In Emerging Microbes & Infections, (en ligne) (April, 2026), 2651469
En ligne : www.tandfonline.com[...]

A novel Merbecovirus, designated Cam-2023, has been identified in Pipistrellus pipistrellus in France through non-invasive surveillance. Phylogenetic analysis demonstrates that Cam-2023 belongs to a Merbecovirus clade previously associated with ACE2 usage in closely related viruses detected in the Netherlands and Russia. While the receptor usage of Cam-2023 remains to be functionally validated, sequence similarities within the Spike protein, particularly the receptor-binding domain, suggest a putative association with a Merbecovirus clade previously associated with ACE2 usage. This discovery broadens the known host diversity of this lineage and extends its geographical range to Western Europe. Our findings highlight the importance of continuous surveillance in European bat populations to better characterize the distribution and zoonotic potential of such high-risk coronaviruses.

Exposure to a mixture of organic pollutants in a threatened freshwater turtle Emys orbicularis: effects of age, sex, and temporal variation

Wed, 11 Mar 2026 16:05:55

de Leslie-Anne Merleau, Olivier Lourdais, Anthony Olivier, Marion Vittecoq, Fabrice Alliot, Sira Traore, Carole Leray, Aurélie Goutte
In Peer Community Journal, 6 (March, 2026)
En ligne : peercommunityjournal.org[...]

Freshwater ecosystems constitute major sinks for organic contaminants, increasing anthropogenic pressures and threatening the unique biodiversity they harbour. In addition to persistent legacy compounds, such as polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs), various pollutants are less persistent but are chronically released, including polycyclic aromatic hydrocarbons (PAHs), phthalate diesters (PAEs), pyrethroid pesticides, and insect repellent. Heretofore, these pollutants have received insufficient attention in freshwater reptiles, considering their potential to trigger detrimental effects on organisms. During two years (2019 and 2020), we quantified plasma levels of 46 compounds from 7 chemical families in two monitored populations of the protected European pond turtle (Emys orbicularis) in the Camargue wetland, France. PAHs and PAEs were found predominantly and concomitantly, with similar occurrences and levels in the two populations. We observed similar inter-annual variations in PAHs and PAEs with differences between males and females, highlighting the need for a better assessment of the role of sex in the exposure pathway and the toxicokinetics of contaminants, especially in turtles. The negative relationship between PAH levels and age, as well as the high intra-individual variation in levels of both contaminant families, provides further evidence of limited bioaccumulation of these pollutants in the blood of E. orbicularis. This could be explained by the metabolic biotransformation of parent compounds, highlighting the need to quantify the levels of PAH metabolites and phthalate monoesters. Finally, our work underscores the importance of long-term monitoring to better determine the vulnerability of turtle populations already exposed to a wide range of contaminants.

Py-GC-MS/MS quantification of microplastics in vertebrate tissues: Addressing false positives of polyethylene

Wed, 7 Jan 2026 15:52:21

de Florence Nono Almeida, Carole Leray, Magali Albignac, Marion Vittecoq, Karen D. McCoy, Alexandra ter Halle
In Journal of Hazardous Materials, 501 (January, 2026), 140658
En ligne : www.sciencedirect.com[...]

As plastic production continues to rise and waste accumulates, animal species across the planet are being increasingly exposed. However, the fate of plastics within the vertebrate body, and particularly of small microplastics (SMPs, 10–1000 µm), remains largely unknown due to challenges in reliably quantifying their loads. To address this gap, we developed a method based on pyrolysis gas chromatography coupled with tandem mass spectrometry (Py-GC/MS-MS) to quantify SMPs in the Yellow-legged Gull (Larus michahellis), an opportunistic seabird highly exposed to plastic pollution. Five gull carcasses were necropsied under controlled conditions, isolating four organs of the gastrointestinal tract. Sample preparation was undertaken in seven steps, including a potassium hydroxide digestion. Interference from lipids in quantifying polyethylene (PE), a recognized problem for this type of quantification, was addressed by selecting markers with carbon atom chains longer than the aliphatic chains of common lipids (i.e., >22 atoms), enabling us to effectively distinguish PE from biological matrix components. The use of long markers for PE raised the limit of quantification (LOQ) to 50 µg/g, while the LOQs for PMMA (poly(methyl methacrylate)), PP (polypropylene), and PS (polystyrene) were 1 µg/g. For PET (polyethylene terephthalate), the LOQ was 10 µg/g due to the relatively high level of airborne contamination in negative controls. Using this method, microplastic concentrations in gull digestive tissues was found to range over several 100 µg/g dry weight, with one individual showing particularly high exposure to PS and PE. Our method enables a reliable quantification of microplastics and provides a basis for analyzing their impacts on vertebrates.

Spatiotemporal Dynamics of Blood Parasite Infections and Impacts on Avian Health and Reproduction

Wed, 3 Dec 2025 11:08:08

de Marie Buysse, Mathilde Ollagnier, Charly Souc, Marjorie Bruley, Thomas Blanchon, Carole Leray, Marion Vittecoq, Karen D. McCoy
In Molecular Ecology, (en ligne) (December, 2025), e70178
En ligne : onlinelibrary.wiley.com[...]

Parasitic infections are ubiquitous in nature, but their consequences are often difficult to evaluate in wildlife. This is particularly the case for chronic infections for which fitness impacts can be subtle or confounded with other intrinsic and extrinsic factors. Infections by Babesia (Apicomplexa, Piroplasmidae) are widespread in wildlife, but little is known about their impacts on host health. Here, we evaluated the dynamics and possible fitness consequences of infection by Babesia sp. YLG, a recently described parasite infecting yellow-legged gulls (Larus michahellis). Using a qPCR assay developed for Babesia sp. YLG, we found that prevalence was much higher in chicks compared with adults. In chicks, infection depended on the colony and was tightly related to nest infestation by the tick vector Ornithodoros (Alectorobius) maritimus; this was not the case for adult birds. Infection intensities changed over time in chicks, increasing up to approximately 37 days old and then declining. Infection was associated with reduced body condition and fledging success for adults. In chicks, infection was significantly linked to reduced growth rates, even after accounting for the additive effect of ticks. However, no relationship was detected between infection and fledging date, migration strategy or flight distances measured on a subset of GPS-tagged juvenile birds. Through its subtle effects on fitness and reproductive success, infection by Babesia sp. YLG may have significant consequences for host demography and work focused on long-term dynamics is now called for to better understand how this parasite may shape the ecology and evolution of seabird populations.

High prevalence and diversity of alphacoronaviruses in bats in Southern France

Thu, 28 Aug 2025 11:56:59

de Océane Rieu, Anaïs Dufau, Jordan Meliani, Lionel Brazier, Marion Vittecoq, Carole Leray, Anthony Olivier, Emmanuel Cosson, Frederic Thomas, Eric Leroy, et al.
In EcoHealth, (en ligne) (August, 2025)
En ligne : doi.org[...]

Zoonotic diseases are increasingly affecting global health, making it crucial to understand viral dynamics in wildlife reservoirs like bats. Bats are well-established coronavirus reservoirs, and their proximity to human habitats in France raises concerns about zoonotic transmission. This study investigates the prevalence, diversity, and phylogenetic relationships of coronaviruses in bats from the Camargue and Eastern Provence, two ecologically distinct regions. A total of 785 bat guano samples were collected non-invasively, with 154 (19.6%) testing positive for coronavirus RNA, among the highest infection rates observed in European studies. Camargue samples were entirely from Pipistrellus bats, with a prevalence of 20.1%, while Provence showed greater genus diversity and prevalence ranging from 1.3% to 35.6%. Phylogenetic analysis identified Alphacoronaviruses in four subgenera: Nyctacovirus, Myotacovirus, Decacovirus, and Minunacovirus, alongside unclassified sequences. No coronavirus related to human-infecting strains (e.g., HCoV-229E) was detected. However, the combination of high prevalence, proximity to humans, and potential for host-switching led to the investigation of coronavirus infection in bats, a topic with limited data in France. These findings highlight the ecological role of bats and the importance of continuous viral monitoring, filling a gap in knowledge about coronavirus circulation in European bat populations.

Blood levels of metallic trace elements are influenced by sex, age and habitat in the European pond turtle (Emys orbicularis)

Fri, 22 Nov 2024 11:34:53

de Leslie-Anne Merleau, Aurélie Goutte, Anthony Olivier, Marion Vittecoq, Paco Bustamante, Carole Leray, Olivier Lourdais
In Science of The Total Environment, 954 (December, 2024), 177487
En ligne : linkinghub.elsevier.com[...]

Metallic trace elements (MTEs) constitute a major source of chemical pollution and represent a threat to aquatic ecosystems and organisms. Important variation in contamination may exist at a local scale in relation to the environment (hydrosystem, trophic ressources) and individual traits (age, sex). Heretofore, the factors influencing MTEs exposure of freshwater reptiles in temperate regions are not fully understood. Freshwater turtles have a relatively high trophic position and a long lifespan, thus being potentially highly exposed due to bioaccumulation and bioamplification processes. We investigated MTE blood concentrations from two populations of the European pond turtle (Emys orbicularis) in the Camargue wetland (France). These populations, monitored since 1997, differ in their habitat and exposure (irrigation versus drainage canal). In this study, we detected 7 MTEs (Cu, Fe, Hg, Mn, Pb, Se, and Zn) which levels depended on site and individual characteristics. Hg was positively related to body size and age, indicating an increase of exposure in older individuals. We found differences between males and females with the interaction with body size for Pb and Se and with age for Pb. Nitrogen and carbon stable isotopes varied only marginally between individuals and were poorly associated with MTEs concentrations, showing that trophic position might not explain MTEs contamination for these populations. At the individual level, Hg, Pb, and Se blood values were repeatable over years. Further studies should concentrate on potential ecophysiological effects to such exposure, especially since we recently evidenced that these populations of E. orbicularis are highly exposed to organic contaminants, which can lead to synergistic effects.

Spatial variation of mercury contamination in yellow-legged gulls (Larus michahellis) in the Western Mediterranean

Thu, 3 Oct 2024 11:30:11

de Laura Patier, Paco Bustamante, Karen D. McCoy, Gaël Guillou, Abdessalem Hammouda, Carole Leray, Gonzalo Fernando Martínez Salcedo, Ana Payo-Payo, Gauthier Poiriez, Raul Ramos, et al.
In Environmental Pollution, 362 (December, 2024), 124992
En ligne : www.sciencedirect.com[...]

Mercury (Hg) is a global pollutant of major concern in marine and coastal environments. In the Mediterranean Sea, Hg concentrations in biota are higher than in other seas, even when seawater concentrations are similar. Seabirds, as marine top predators, can reflect Hg contamination on a large spatial scale. By sampling seabirds at 17 different breeding colonies, we evaluated Hg concentrations of yellow-legged gulls (Larus michahellis) in the occidental Mediterranean basin in 2021 and 2022. More specifically, we investigated spatial variation of Hg contamination in both chicks and adults as well as associated toxicological risks through the use of blood and feathers, which reflect contamination over different periods of the year. The highest concentrations in chicks were found in Djerba (Tunisia) with blood Hg values of (mean ± SD) 1.69 ± 0.51 μg g−1 dry weight (dw). Adults were most contaminated in Djerba and Dragonera (Balearic Islands, Spain) with blood Hg concentrations of respectively 3.78 ± 2.54 and 5.25 ± 3.73 μg g−1 dw. Trophic ecology was investigated using stable isotope analyses (δ13C, δ15N and δ34S as proxies of feeding habitat and diet), and showed that spatial variation in Hg was mainly driven by foraging habitat in both chicks and adults. Low Hg concentrations were related to the use of anthropogenic food sources. An effect of colony location was also found, suggesting spatial differences in local environmental pollution transfer up to seabirds. Our results also supported the use of δ34S to discriminate between marine and continental foraging habitats in generalist seabirds. This study provides new insights onto the spatial distribution of Hg contamination in a widespread seabird, reporting some of the highest Hg values recorded for this species. Populations with highest concentrations are of potential concern regarding toxicological risks.

Mercury contamination and potential health risk to French seabirds: a multi-species and multi-site study

Mon, 16 Sep 2024 14:08:25

de Prescillia Lemesle, Alice Carravieri, Gauthier Poiriez, Romain Batard, Aurélie Blanck, Armel Deniau, Gilles Faggio, Jérôme Fort, Fabrice Gallien, William Jouanneau, et al.
In Science of The Total Environment, 952 (November, 2024), 175857
En ligne : www.sciencedirect.com[...]

Mercury (Hg) is a naturally occurring, highly toxic element whose circulation in ecosystems has been intensified by human activities. Hg is widely distributed, and marine environments act as its main final sink. Seabirds are relevant bioindicators of marine pollution and chicks are particularly suitable for biomonitoring pollutants as they reflect contamination at short spatiotemporal scales. This study aims to quantify blood Hg contamination and identify its drivers (trophic ecology inferred from stable isotopes of carbon (δ13C) and nitrogen (δ15N), geographical location, chick age and species) in chicks of eight seabird species from 32 French sites representing four marine subregions: the English Channel and the North Sea, the Celtic Sea, the Bay of Biscay and the Western Mediterranean. Hg concentrations in blood ranged from 0.04 μg g−1 dry weight (dw) in herring gulls to 6.15 μg g−1 dw in great black-backed gulls. Trophic position (δ15N values) was the main driver of interspecific differences, with species at higher trophic positions showing higher Hg concentrations. Feeding habitat (δ13C values) also contributed to variation in Hg contamination, with higher concentrations in generalist species relying on pelagic habitats. Conversely, colony location was a weak contributor, suggesting a relatively uniform Hg contamination along the French coastline. Most seabirds exhibited low Hg concentrations, with 74 % of individuals categorized as no risk, and < 0.5 % at moderate risk, according to toxicity thresholds. However, recent work has shown physiological and fitness impairments in seabirds bearing Hg burdens considered to be safe, calling for precautional use of toxicity thresholds, and for studies that evaluate the impact of Hg on chick development.

Among-colony variation in plastic ingestion by Yellow-legged gulls (Larus michahellis) across the western Mediterranean basin

Wed, 5 Jun 2024 15:49:23

de Florence Nono Almeida, Carole Leray, Charly Souc, Sara Scotto, Slaheddine Selmi, Abdessalem Hammouda, Raul Ramos, Alexandra ter Halle, Karen D. McCoy, Marion Vittecoq
In Marine pollution bulletin, 204 (July, 2024), 116508
En ligne : www.sciencedirect.com[...]

The Mediterranean region is both a hotspot for biodiversity and for the accumulation of plastic pollution. Many species are exposed to this pollution while feeding, including a wide diversity of seabirds. Our objective was to investigate spatial variation in the quantity and types of plastic ingested by Yellow-legged gulls using information obtained from regurgitated pellets collected in 11 colonies. Anthropogenic debris, and particularly plastic, was found in pellets from all colonies, but the amount varied considerably. This among-colony difference was stable over the two years of study. The presence of marine prey and the proportion of agricultural area around the colonies significantly influenced the number of ingested plastics. As landfills close and garbage management improves, the availability of anthropogenic waste should decline. Following the response of gulls to these changes will be particularly useful for monitoring plastic pollution and for understanding the response of opportunistic wildlife to environmental modifications.

No detrimental effects of wing-harnessed GPS devices on the breeding performance of Yellow-legged Gulls (Larus michahellis): A multi-colony evaluation

Wed, 26 Jun 2024 16:19:01

de Charly Souc, Carole Leray, Thomas Blanchon, Thomas Dagonet, Marion Vittecoq, Raul Ramos, Karen D. McCoy
In Ibis, (en ligne) (June, 2024)
En ligne : onlinelibrary.wiley.com[...]

A recent study revealed that wing-harnessed tracking devices negatively affected reproductive success of Great Black-backed Gulls Larus marinus. To evaluate the generality of this effect in large gulls, we investigated the reproductive performance associated with the same type of GPS-mounted system in four Mediterranean breeding colonies of the Yellow-legged Gull Larus michahellis in 2022. We found no significant difference in reproductive parameters among adults handled with a mounted device, adults handled with no device, and controls, and no interaction with colony of origin. The impact of the GPS harness system on short-term reproduction is therefore not generalizable among larid species, and should be tested and reported whenever a new tracking programme is employed.

Pesticide concentrations in a threatened freshwater turtle (Emys orbicularis): Seasonal and annual variation in the Camargue wetland, France

Tue, 21 Nov 2023 15:28:58

de Leslie-Anne Merleau, Olivier Lourdais, Anthony Olivier, Marion Vittecoq, Gabriel Blouin-Demers, Fabrice Alliot, Louisiane Burkart, Yvann Foucault, Carole Leray, Emmanuelle Migne, et al.
In Environmental Pollution, Online November (November, 2023), 11
En ligne : linkinghub.elsevier.com[...]

Wetlands are among the most threatened ecosystems on the planet and pollution is a major factor causing the decline of wetland biodiversity. Despite the increasing use of pesticides, their fate and effects on freshwater reptiles remain largely unknown. We studied the European pond turtle (Emys orbicularis), a long-lived species at risk with a high exposure potential to pesticides. Between 2018 and 2020, we measured 29 pesticides and metabolites in 408 blood samples of turtles from two populations in the Camargue wetland (France). We were able to quantify 24 compounds and at least one pesticide or one degradation product in 62.5% of samples. Pesticide occurrences and concentrations were low, except for a herbicide widely used in rice cultivation and locally detected in water: bentazone that reached high blood concentrations in E. orbicularis. The occurrence and the concentration of pesticides in E. orbicularis blood depended mainly on the site and the sampling date in relation to pesticide application. Individual characteristics (sex, age, body condition) did not explain the occurrence or the concentration of pesticides found in turtle blood. Assessing the exposure of aquatic wildlife to a cocktail of currently-used pesticides is a first and crucial step before studying their effects at the individual and population levels.

A soft tick vector of Babesia sp. YLG in Yellow-legged gull (Larus michahellis) nests

Mon, 11 Dec 2023 14:18:11

de Claire Bonsergent, Marion Vittecoq, Carole Leray, Maggy Jouglin, Marie Buysse, Karen D. McCoy, Laurence Malandrin
In Peer Community Journal, 3 (August, 2023)
En ligne : peercommunityjournal.org[...]

Babesia sp. YLG has recently been described in Yellow-legged gull (Larus michahellis) chicks and belongs to the Peircei clade in the new classification of Piroplasms. Here, we studied Babesia sp. YLG vectorial transmission by ticks in the simplified environment of a single seabird breeding colony where the Yellow-legged gull is the sole vertebrate host, Ornithodoros maritimus (syn. Alectorobius maritimus) the sole tick species, and Babesia sp. YLG is the only blood parasite species detected in chicks of the colony. We collected ticks over four years, maintained certain individuals through moulting or oviposition, and dissected fresh ticks to isolate different organs and test for the presence of the parasite using molecular assays. We report the first strong evidence of a Piroplasmidae transmitted by a soft tick. Indeed, Babesia sp. YLG DNA was detected in the salivary glands of nymphs, females and males, a necessary organ to infect for transmission to a new vertebrate host. Parasite DNA was also found in tick ovaries, which could indicate possible transovarial transmission. Our detection of Babesia sp. YLG DNA in several male testes and in endospermatophores, and notably in a parasite-free female (uninfected ovaries and salivary glands), raise the interesting possibility of sexual transmission from infected males to uninfected females. Future work in this system will now need to focus on the degree to which the parasite can be maintained locally by ticks and the epidemiological consequences of infection for both O. maritimus and its avian host.

Field margins as substitute habitat for the conservation of birds in agricultural wetlands

Mon, 21 Aug 2023 15:21:50

de Pierre Mallet, Arnaud Béchet, Clelia Sirami, François Mesléard, Thomas Blanchon, Francois Calatayud, Thomas Dagonet, Elie Gaget, Carole Leray, Thomas Galewski
In Peer Community Journal, 3 (August, 2023)
En ligne : peercommunityjournal.org[...]

Breeding birds in agricultural landscapes have declined considerably since the 1950s and the beginning of agricultural intensification in Europe. Given the increasing pressure on agricultural land, it is necessary to identify conservation measures that consume little productive land. We tested the compensation hypothesis which states that field margins may represent substitute habitats for bird species in agricultural wetlands. We monitored bird species in 86 crop fields in rice paddy landscapes of Camargue (southern France), a wetland of international importance for birds. We investigated whether the area of three types of field margins (reed strips, grass strips and hedgerows) within a 500 meter buffer around the centroid of each crop fields had an effect on the abundance of bird species from three groups defined based on their primary habitat (reedbeds, grasslands, and forest edge species). We controlled for the area of each type of semi-natural habitat (wetlands, grasslands, and woodlands), crop diversity (rice, wheat, alfalfa, rape, and market gardening) and mean crop field size. Results show partial support of the compensation hypothesis with species-dependent responses to primary and substitute habitat area. Some species within the reedbed and grassland bird guilds are favored by the area of their primary habitat as well as by the area of field margins, in line with the compensation hypothesis. Eurasian reed warbler is favored by the area of both wetlands and reed strips. Corn bunting is favored by grassland and grass strip areas. We could not confirm the compensation hypothesis for other species. However, this may be due to the fact that most of these species did not respond to their primary habitat. These results therefore suggest that field margins may represent substitute habitats for some species but further studies, in contexts where species are strongly associated with their primary habitat, would be needed to confirm the generality of this hypothesis. Our results also suggest that species response to increasing the area of a field margin type may vary among guilds and even within guilds. Therefore, it may be difficult to favor all species within a given landscape and management actions may need to be tailored to whichever species are locally associated with the highest conservation priority. To tackle this challenge, it may be necessary to design landscape management actions at different spatial scales.

Changes in plastic ingestion by yellow-legged gulls (Larus michahellis) over the breeding season

Fri, 20 Jan 2023 16:13:56

de Florence Nono Almeida, Carole Leray, Justine Boutry, Alexandra ter Halle, Marion Vittecoq, Jennifer F. Provencher, Karen D. McCoy
In Marine pollution bulletin, 187 (February 2023), 9
En ligne : www.sciencedirect.com[...]

Gulls can be particularly vulnerable to ingesting plastics when using anthropogenic food sources, with potential consequences for survival and reproductive success. Although birds are known to switch foraging habitats over the breeding season to provide higher quality food for chick provisioning, it is unclear what this means regarding the ingestion of plastics. Here, we tested whether breeding gulls decrease the amount of plastic ingested during reproduction by collecting pellets from a series of monitored nests at a large yellow-legged gull (Larus michahellis) colony in southern France. We found at least one plastic item in 83.9 % of the analyzed pellets, with the most abundant plastic type being polyethylene-based sheet plastic. As predicted, we found a slight decrease in the number of plastic items in pellets at chick hatching. These results suggest that gulls, like other birds, may adjust foraging habits to provide more digestible, less risky, food to chicks.

Characterization and diversity of Babesia sp. YLG, a new member of the Peircei group infecting Mediterranean yellow-legged gulls (Larus michahellis)

Mon, 25 Oct 2021 14:36:39

de Claire Bonsergent, Marion Vittecoq, Carole Leray, Louisiane Burkart, Karen D. McCoy, Laurence Malandrin
In Ticks and Tick-borne Diseases, Online (October, 2021), 101852
En ligne : www.sciencedirect.com[...]

Avian infecting piroplasms are largely under-studied compared to other hemoparasites, and this paucity of information has blurred our phylogenetic and biological comprehension of this important group as a whole. In the present study, we detected and characterized Babesia from yellow-legged gull (Larus michahellis) chicks from a colony in southern France. Based on morphological and molecular characterizations, a new Babesia species belonging to the Peircei group, a clade of avian-specific piroplasms, was identified. Due to the complexity of species delineations and the low number of parasites characterized in this clade to date, a species name was not yet attributed; we refer to it for now as Babesia sp. YLG (Yellow-Legged Gull). High prevalence (85% and 58% in 2019 and 2020, respectively) and high parasitemia (up to 20% of parasitized erythrocytes) were recorded in chicks, without any obvious clinical signs of infection. Although the 16 isolates had identical 18S rRNA gene sequences, 6 genetic variants were described based on partial cox1 sequencing, with evidence of chicks co-infected by two variants. Transmission of Babesia sp. YLG via the soft tick Ornithodoros maritimus is discussed.

Genetic diversity and relationships of the liver fluke Fasciola hepatica (Trematoda) with native and introduced definitive and intermediate hosts

Wed, 4 Nov 2020 13:41:51

de Antonio A. Vázquez, Emeline Sabourin, Pilar Alda, Clémentine Leroy, Carole Leray, Eric Carron, Stephen Mulero, Céline Caty, Sarah Hasfia, Michel Boisseau, et al.
In Transboundary and Emerging Diseases, 68(4) (November, 2020)
En ligne : onlinelibrary.wiley.com[...]

Fasciolosis is a worldwide spread parasitosis mainly caused by the trematode Fasciola hepatica. This disease is particularly important for public health in tropical regions, but it can also affect the economies of many developed countries due to large infections in domestic animals. Although several studies have tried to understand the transmission by studying the prevalence of different host species, only a few have used population genetic approaches to understand the links between domestic and wildlife infections. Here, we present the results of such genetic approach combined with classical parasitological data (prevalence and intensity) by studying domestic and wild definitive hosts from Camargue (southern France) where fasciolosis is considered as a problem. We found 60% of domestic hosts (cattle) infected with F. hepatica but lower values in wild hosts (nutria, 19%; wild boars, 4.5%). We explored nine variable microsatellite loci for 1,148 adult flukes recovered from four different populations (non-treated cattle, treated cattle, nutria and wild boars). Populations from the four groups differed, though we found a number of migrants particularly non-treated cattle and nutria. Overall, we detected 729 different multilocus genotypes (from 783 completely genotyped individuals) and only 46 genotypes repeated across samples. Finally, we experimentally infected native and introduced intermediate snail hosts to explore their compatibility with F. hepatica and assess the risks of fasciolosis expansion in the region. The introduced species Galba truncatula and Pseudosuccinea columella attained the higher values of overall compatibility in relation to the European species. However, concerning the origin, sympatric combinations of G. truncatula were more compatible (higher prevalence, intensity and survival) than the allopatric tested. According to our results, we should note that the assessment of epidemiological risks cannot be limited to a single host–parasite system, but should focus on understanding the diversity of hosts in the heterogeneous environment through space and time.