Emerging infectious diseases are one of the biggest challenges in a globalized world. To date, resources have been allocated to prevent and control the spread of zoonotic and livestock pathogens. We argue that, in line with the One Health approach, equitable efforts, financial resources, attention, and coordination are required for wildlife-only pathogens to halt biodiversity loss. Deploying the amphibian fungus Batrachochytrium salamandrivorans as a model, we demonstrate the unbalanced efforts among countries in Europe regarding surveillance, disease response, prevention, public outreach, and research. We compare investments with B. salamandrivorans l-free countries such as the United States, concluding that structural resources are urgently needed to curb the effects of this fungus within Europe and beyond. We encourage dialogue among authorities, researchers, and stakeholders and propose a coordinated European Union-level program of €6-10 million over 5-7 years to implement B. salamandrivorans action plans and define structural funding requirements for future wildlife disease mitigation.

ABSTRACT 1- Temporary fences are used to prevent amphibians from accessing dangerous areas. These fences can be built out of different materials and field studies have shown that some of them still allow for trespassing. 2- In this study we compared, in controlled conditions and using experimental arenas, the effectiveness and efficiency of the three most commonly used materials for temporary amphibian fences (polyethylene tarp, polyethylene netting, and wire meshing) and of the presence of an overhang, on two amphibian species with distinct modes of locomotion (walker/short-distance jumper; long-distance jumper). The polyethylene tarp fence, and fences equipped with an overhang, were the only designs able to stop every individual for three consecutive trials. 3- Fences that were not smooth or equipped with an overhang could be crossed at any height by both species. 4- For non-climbable fences, long-distance jumper species required a 60 cm high fence to be stopped while the walker/short-distance jumper species only required 20 cm. 5- The walker/short-distance jumper individuals interacted 1.7 times more with the polyethylene netting and wire meshing than the polyethylene tarp, due to either differences in opacity between materials or the impossibility to climb on the tarp. The long-distance jumper species was not deterred by the tarp fence and interacted equally with all materials. 6- When considering price, durability and ease of use while maintaining effectiveness, the polyethylene netting fences equipped with an overhang were the most efficient option for long-term use. 7- Synthesis and applications: amphibian fences should systematically be equipped with a 10 cm overhang at their top to ensure their effectiveness. Polyethylene tarp is the best option for short-term use while polyethylene netting is the best option for long-term use.

Semi-aquatic mammals lie at the intersection of several key conservation issues such as wetland deterioration or species invasions, and monitoring their distribution in space and time is essential to inform conservation strategies. However, gathering information about their presence is challenging due to their elusive lifestyle and generally low abundance. The Eurasian otter (Lutra lutra), a near-threatened and strictly protected species in Europe, is currently recolonizing part of its historical range. Its high conservation interest, combined with a dynamic more commonly associated with range-expanding or invasive species, makes it a particularly compelling case study. Otter monitoring has traditionally relied on scat surveys, but recent environmental DNA (eDNA) and camera-trapping initiatives have emerged offering promising complementary tools. Yet, these approaches have rarely been formally compared, either to one another or across regions. Here, we compared the efficiency of spraint surveys, camera traps, and eDNA for detecting otters, and assessed how their performance varied among four catchments in southern France where the species is known to be present. All three methods provided otter detections with varying efficiency. Scat surveys were the most effective method, with an average detection probability of 0.71 and no strong variability between catchments. Although camera-traps had the lowest detection rate, they provided detections at two of the four sites where no spraint was found, highlighting the complementarity of these two approaches. Detection rates varied greatly between individual cameras rather than between catchments, underscoring sensitivity to camera placement. eDNA showed important variability between catchments, with detection probabilities differing by roughly sixfold across regions. All in all, our results highlight differences in efficiency between methods and across environmental conditions, and show the value of combining approaches for future monitoring programs.

The common spadefoot toad (Pelobates fuscus) is a declining amphibian whose movement patterns and terrestrial habitat use are not well known. The daily positions of 51 common spadefoot toads were monitored by telemetry at two sites along the Lower Rhine valley, France. Fluorescent pigments were used to monitor the nocturnal movements of 91 individuals in three populations in the same area. This study aimed to (i) characterise terrestrial movement patterns and estimate home ranges, and (ii) identify the preferred habitat types of this fossorial amphibian. The median home range size was 0.35 ha. We counted an average of 6.9 burrows per individual and individuals spent an average of 2.7 days in a burrow. The average distance travelled in 24 h was 12.5 m with a maximum of 136.7 m. The average distance to the nearest breeding pond was 245.6 m, and this distance could be up to 777 m. The common spadefoot avoided shrubby areas, preferring forest litter (especially forest edges) and corn fields for its daily burrows. These results highlight the importance of protecting a wide range of habitats for this sedentary species with a predominantly terrestrial lifestyle.

Plastic forms the majority (i.e. 75%) of marine waste with 14.5 million tons per year of dumped into the oceans. Once at sea, sunlight, wind, and wave action break down macroplastic waste into small particles. These microplastics (MPs, particles between 0.1 µm and 5 mm), which can also directly originate from industrial production are ubiquitous and are likely to persist in the marine environment for centuries. Recent studies show that the range of marine animals capable of ingesting these MPs spans the entire marine fauna. The effects of MP ingestion are diverse and vary between taxa: reduced food assimilation efficiency, delayed growth, negative effects on reproduction, reduced energy reserves due to reduced feeding activity, impaired cognitive abilities, decrease of the survival and fecundity rates, increase of the mortality rates, promotion of inflammatory, responses, and disruption of the endocrine system and fomites of pathogens. Due to the complexity of their life history traits (long lifespan, highly migratory species, oceanic or neritic lifestyle depending on life stage) and their feeding habits (visual feeders mistaking their prey for plastic waste), marine turtles appear to be highly vulnerable to plastic contamination. In loggerhead sea turtles, MPs are mostly localized in the intestine, compared to the esophagus and stomach. Despite their importance as key species for monitoring MP contamination and effects, the effect MPs concentratins and composition on the turtle gut microbiota and on their health has never been investigated.The present study aims to i) quantify and characterize the MP contamination in loggerhead turtles, and ii) measure their impact on the gut microbiota and health indices of loggerhead turtles (Caretta caretta) of the western Mediterranean. For this purpose, we collected stool, blood, saliva and scales samples from 112 live loggerhead turtles along the eastern Spanish coast and we related the abundance and composition of MPs to several turtle health indicators such as external parasitosis, nutritional efficiency, immuno-inflammatory response at the intestinal barrier, liver function and chronic stress as well as the diversity of the gut microbiota. Seventy-four percent of the loggerhead turtles in the study were contaminated with microplastics with an average of 7.90 ± 10.89 microplastics per gram of feces. The most common polymers are polyethylene, polyester, and polyamide (44.82%, 27.23% and 12.11% respectively). Several significant relationship between microplastics abundance and the microbial composition of the intestinal microbiota, the abundance of immune cells or glucose levels suggest that MPs have a potential impact on the health of loggerhead turtles, notably by modifying the structure of the bacterial communities of the intestinal microbiota (increase in specific richness) but also by disrupting the immune system and glucolipid metabolism.

Early detection is a crucial tool for identifying the spread of invasive species. In this study, we validated a probe-based quantitative polymerase chain reaction (qPCR) assay for the detection of the invasive Blue Crab, Callinectes sapidus, in the Mediterranean Sea, using 22 initial eDNA environmental samples (eDNA) collected from three coastal lagoons. A subsequent large-scale eDNA sampling campaign (61 samples in 31 sites), conducted in collaboration with local stakeholders, was carried out to map the distribution of C. sapidus along the Occitanie coastline (Western Mediterranean, France). Using eDNA probe-based qPCR, C. sapidus was detected in 32 out of the 61 samples (52%), confirming its presence in 24 out of 31 sites surveyed, including the 13 lagoons where its occurrence had already been reported, as well as two additional lagoons and at sea where no prior records existed. Our results demonstrate the utility of eDNA probe-based qPCR for effective monitoring of the invasive Blue Crab. The integration of eDNA analysis with citizen science observations enhances the monitoring framework, facilitating early detection and contributing to improved management strategies at the very beginning of species colonization when practical actions could be implemented.

European amphibians such as the common spadefoot toad (Pelobates fuscus (Laurenti, 1768)) exhibit alarming declines across large parts of their range, despite extensive legislation aimed at conservation. As knowledge about the genetic background of a species has become crucial for conservation assessment, we investigated nuclear genetic diversity and structure of P. fuscus, based on microsatellite loci. Clustering revealed major groups corresponding to postglacial colonization patterns. Additionally, we found contrasting patterns of genetic diversity across the 66 studied populations, reflecting the conservation status of the species in Europe and with marked genetic impoverishment across most populations in the northwestern part of the species’ distribution range. Our findings provide genetic information on the conservation status of the common spadefoot toad across Europe, emphasizing the need for urgent conservation efforts. We recommend further genetic monitoring, habitat restoration and potential translocations to safeguard the species in the face of ongoing challenges.

In aquatic ecosystems, environmental DNA (eDNA) can be collected from water samples to produce species inventories. One method for this is passive eDNA sampling, whose development for aquatic biodiversity monitoring is in its early stages. While several materials have been successfully tested for passive eDNA samplers (PEDS), methodological advances are still needed to explore their versatility as a complement to the more common method of active filtration. This study tested for the first time a PEDS using human-crafted material in controlled marine mesocosms (1 m3) containing one species, the European seabass (Dicentrarchus labrax) in different conditions of fish density (1, 5, 10, 100 fish per m3) and exposure times (30 min, 2 h, 8 h, 24 h). We then tested the influence of another source of eDNA on the sampler's performance by introducing another species, the Pacific oyster (Magallana gigas). In addition, we compared the efficacy of the method with active filtration. The PEDS we produced consisted of a small electrospun polyacrylonitrile (PAN) membrane encapsulated in a custom-made 3D-printed frame. Each sampler is low-cost, easy to manipulate, highly replicable, and customizable. A specific quantitative polymerase chain reaction-based assay for the seabass was developed. Results were analyzed with multiscale occupancy modeling and continuous response variable modeling. We found that the PAN-PEDS efficiently collected eDNA in a large volume (1 m3) of renewed water (1 m3/h), with a clear positive effect of high fish density on fish detection. The introduction of oysters did not significantly influence detection. Regarding exposure times, a range of results were obtained that could be attributed to the unreached equilibrium between eDNA shedding and degradation. While active eDNA collection (30 L) outperformed PAN-PEDS, the ongoing development of passive methods can provide new insights in aquatic species monitoring when spatio-temporal eDNA collection is required.

Population genetics is a powerful tool for studying evolutionary processes and informing conservation biology. Traditional approaches typically rely on tissue sampling, which poses challenges in aquatic environments where specimen collection is often difficult. Recent efforts to conduct non-invasive studies using environmental DNA (eDNA) have shown promise but face limitations. For instance, the use of a limited number of markers or the unintended capture of DNA fragments from off-target species can hinder their effectiveness for population genetic studies. As a proof of concept of species-specific genome-wide nuclear loci detection from eDNA, we targeted the common frog, Rana temporaria, using a comparative experimental design. Field eDNA replicates were collected from four Alpine ponds, alongside tissue samples from 20 live tadpoles per pond. These tadpoles were also placed in separate tanks to collect eDNA under controlled conditions. Frog DNA from a subset of individuals was analysed through ddRAD genotyping and subsequently used to design custom probes for capturing frog nuclear loci from eDNA samples and individually collected tissues, using a modified hyRAD protocol. Although we observed substantial heterogeneity in the genetic data retrieved across replicates, the number of nuclear loci recovered in eDNA samples using hyRAD was in line with those obtained through classical ddRAD, proving sufficient to investigate genetic variation. We identified a total of 17,617 nuclear single nuclear polymorphisms shared across individual, pond eDNA and tank eDNA samples, enabling us to detect genetic structuring across sampling locations, consistent with individual-based estimates. Our study opens new perspectives and corroborates the potential of eDNA for conducting non-invasive population genomics analyses by using, for the first time, thousands of genome-wide nuclear markers and highlights areas for further improvement.

Wildlife must adapt to human presence to survive in the Anthropocene, so it is critical to understand species responses to humans in different contexts. We used camera trapping as a lens to view mammal responses to changes in human activity during the COVID-19 pandemic. Across 163 species sampled in 102 projects around the world, changes in the amount and timing of animal activity varied widely. Under higher human activity, mammals were less active in undeveloped areas but unexpectedly more active in developed areas while exhibiting greater nocturnality. Carnivores were most sensitive, showing the strongest decreases in activity and greatest increases in nocturnality. Wildlife managers must consider how habituation and uneven sensitivity across species may cause fundamental differences in human–wildlife interactions along gradients of human influence.

Spatial and temporal monitoring of species threatened with extinction is of critical importance for conservation and ecosystem management. In the Mediterranean coast, the fan mussel (Pinna nobilis) is listed as critically endangered after suffering from a mass mortality event since 2016, leading to 100% mortality in most marine populations. Conventional monitoring for this macroinvertebrate is done using scuba, which is challenging in dense meadows or with low visibility. Here we developed an environmental DNA assay targeting the fan mussel and assessed the influence of several environmental parameters on the species detectability in situ. We developed and tested an eDNA molecular marker and collected 48 water samples in two sites at the Thau lagoon (France) with distinct fan mussel density, depths and during two seasons (summer and autumn). Our marker can amplify fan mussel DNA but lacks specificity since it also amplifies a conspecific species (Pinna rudis). We successfully amplified fan mussel DNA from in situ samples with 46 positive samples (out of 48) using ddPCR, although the DNA concentrations measured were low over almost all samples. Deeper sampling depth slightly increased DNA concentrations, but no seasonal effect was found. We highlight a putative spawning event on a single summer day with much higher DNA concentration compared to all other samples. We present an eDNA molecular assay able to detect the endangered fan mussel and provide guidelines to optimize the sampling protocol to maximize detectability. Effective and non-invasive monitoring tools for endangered species are promising to monitor remaining populations and have the potential of ecological restoration or habitat recolonization following a mass mortality event.

Many graph-based studies consider just one habitat type (breeding habitat) and one ecological process (dispersal) when measuring connectivity. However, in the course of their life cycle, some species use different habitats and are particularly sensitive to their spatial arrangement. We propose a new graph modeling approach that considers heterogeneous habitats and movements when assessing connectivity. Our hypothesis is that a multiple habitat approach is more relevant than a single habitat approach for studying the relationships between connectivity and composite habitat species occurrence. We constructed a bipartite graph with separate categories of nodes for aquatic and terrestrial habitats and an inter-habitat link set. Different connectivity values were measured from the graph depending on the ecological process under study. We then compared our models against field observation data for amphibian communities and tested whether multiple habitat connectivity models provide better predictions. Multiple habitat connectivity was as effective as single habitat connectivity, and often more so, in explaining the presence, abundance, and species richness of amphibian communities. Application to habitat restoration revealed that connectivity gains vary greatly depending on the ecological process, emphasizing the importance of links connecting habitats of different types. Multiple habitat graphs appear promising for incorporating habitat and movement heterogeneity into ecological network modeling. We encourage further theoretical and empirical work on multiple habitat connectivity to consolidate the results and evaluate its full potential, especially for global change issues.

Climate change is threatening several montane species across the world, including a large number of endemics, needing the development of forward-looking conservation strategies to foster their future survival. In this context, Species Distribution Models (SDMs) represent a useful method to forecast changes in species’ habitat suitability under different scenarios of global warming, often advising conservation frameworks with credible, defensible and repeatable information. In this paper, we estimate the environmental and bioclimatic suitability for an endemic mountain amphibian (Salamandra lanzai) in the western European Alps through an SDM approach, considering both current and future scenarios, to address short- and long-term management and conservation actions, and to update the current IUCN extinction risk assessment. The ensemble model forecasts predict a dramatic decline of the climatically suitable area for the Lanza’s alpine salamander in the next 20–40 years, even considering an optimistic CO2 emissions scenario, leading to a theoretical extinction of this species in 2100 in case the worst global warming prediction will be actualised. This underlines the urgent need for up-to-date conservation and management strategies to ensure the successful mitigation of climate change effects on S. lanzai, especially by adapting and improving the network of protected areas, immediately removing additional threats and identifying possible management actions able to increase fine-scale habitat suitability and connectivity among populations. In addition, a significant range contraction in the future has to be considered when assessing the extinction risk for this species, possibly exacerbating the effect of other threatening factors, such as the spread of lethal pathogens. Keywords: Salamandra lanzai, ensemble models, environmental suitability, bioclimatic suitability, future projections

Skeletochronology was used to determine the ages of 30 loggerhead sea turtles ( Caretta caretta) found in French Mediterranean waters. Histological sections were performed with 30 humeri collected on stranded C. caretta on the coast of Provence and the Gulf of Lion. Lines of arrested growth (LAGs) were used to evaluate age, considering only one period of arrested growth per year. Two successive LAGs delimit an interval that is proportional to the individual's body growth. In a first step, we created a skeletogram for each individual that identified its LAGs. Secondly, we measured the areas delineating successive intervals to determine individual growth patterns over the years. Two methods were used to deduce sea turtle age from histological sections: the correction factor (CF) method and the growth rate (GR) method, the latter using Von Bertalanffy growth function. Age estimations varied from 4.3 to 24.7 years (mean f SD = 10.1 f 4.8) with the CF method and from 6.2 to 25.6 years (mean f SD = 12.2 f 5.2) with the GR method, with no significant difference between the methods. The study sample was thus mostly composed of juveniles, which is also the most frequent life stage observed in the study area. The annual curved carapace length growth rate calculated with every LAG interval varied from 1.0 to 6.9 cm/year (mean f SD = 3.5 f 1.4, n = 115). High variability in interindividual growth rates were observed, which is of interest in understanding the complex lifecycle of these long-lived marine reptiles.

Riparian and wetland ecosystems (RWEs) are home to many biphasic species, such as amphibians, whose life cycles require both terrestrial and aquatic habitats. This “turquoise infrastructure” has emerged only recently and, because it is complex, little is known to date about how to evaluate its functionality. This paper presents an innovative graph-based model for assessing the connectivity of composite habitats. The model is applied to amphibians at the migration and dispersal ranges in the Essonne department (France). We evaluate the impacts of recent and future (i.e., planned urbanization and drying-up of water bodies due to climate change) landscape transformations on multi-habitat connectivity for these species. Aquatic and terrestrial habitats jointly contribute significantly to the overall habitat connectivity of biphasic species, and changes in landscape configuration can significantly affect composite habitat networks. We find that past land-cover changes had greater negative impacts than those expected from future urbanization. Conversely, the potential future disappearance of ponds because of, for example, climate change could be far more devastating if more than one in four ponds is lost. Turquoise infrastructure supports species with a biphasic lifestyle and makes their multi-habitat networks resilient to urbanization and climate change. In this context, we argue the multi-habitat models can be used relevantly for enhancing and restoring breeding sites, planning, and designing ecological corridors, and/or establishing new protection areas at the landscape scale.

Revue Sciences Eaux & Territoires - Vient de paraître en ligneLa fragmentation du paysage se matérialise par une rupture de connexion au sein des réseaux écologiques. Le concept de trame verte et bleue est apparu comme un outil de protection et de restauration des continuités écologiques dans les territoires. De nouvelles trames écologiques ont récemment été proposées pour identifier d’autres discontinuités écologiques effectives. C’est notamment le cas de la trame turquoise associant la trame bleue et la partie de la trame verte en interaction fonctionnelle. La trame turquoise regroupe ainsi différents types d’habitats aquatiques et terrestres dont dépendent de nombreuses espèces d’amphibiens, d’odonates et autres invertébrés ou encore de chiroptères. Cette nouvelle trame bénéficie d’une attention croissante dans le monde opérationnel, alors même que sa définition et les méthodes de caractérisation ne sont pas encore stabilisées. Cet article propose de contribuer à une meilleure définition et compréhension de la trame turquoise. S’appuyant sur la méthode des graphes paysagers, aujourd’hui largement utilisée pour modéliser les réseaux écologiques et mesurer leur connectivité, le projet INTERFACE a permis le développement d’un protocole innovant de réseau multi-habitats pour tenir compte de l’hétérogénéité des habitats dans l’évaluation de la connectivité de la trame turquoise. Il permet ainsi d’aller au-delà de la délimitation d’une zone tampon autour des cours d’eau et d'identifier les zones fonctionnelles à préserver, les zones vulnérables et les points de conflits où il serait intéressant de restaurer des habitats aquatiques et/ou terrestres pour améliorer les connectivités.

Abstract The authors have requested that this preprint be removed from Research Square.

Environmental policies, including the European Marine Strategy Framework Directive (MSFD), generally rely on the measurement of indicators to assess the good environmental status (GES) and ensure the protection of marine ecosystems. However, depending on available scientific knowledge and monitoring programs in place, quantitative GES assessments are not always feasible. This is specifically the case for marine turtle species, which are listed under the Biodiversity Descriptor of the MSFD. Relying on an expert consultation, the goal of this study was to develop indicators and a common assessment approach to be employed by European Union Member States to evaluate the status of marine turtle populations in the frame of the MSFD. A dedicated international expert group was created to explore and test potential assessment approaches, in coherence with other environmental policies (i.e. Habitats Directive, OSPAR and Barcelona Conventions). Following a series of workshops, the group provided recommendations for the GES assessment of marine turtles. In particular, indicators and assessment methods were defined, setting a solid basis for future MSFD assessments. Although knowledge gaps remain, data requirements identified in this study will guide future data collection initiatives and inform monitoring programs implemented by EU Member States. Overall this study highlights the value of international collaboration for the conservation of vulnerable species, such as marine turtles.

Comparative studies of mortality in the wild are necessary to understand the evolution of aging; yet, ectothermic tetrapods are underrepresented in this comparative landscape, despite their suitability for testing evolutionary hypotheses. We present a study of aging rates and longevity across wild tetrapod ectotherms, using data from 107 populations (77 species) of nonavian reptiles and amphibians. We test hypotheses of how thermoregulatory mode, environmental temperature, protective phenotypes, and pace of life history contribute to demographic aging. Controlling for phylogeny and body size, ectotherms display a higher diversity of aging rates compared with endotherms and include phylogenetically widespread evidence of negligible aging. Protective phenotypes and life-history strategies further explain macroevolutionary patterns of aging. Analyzing ectothermic tetrapods in a comparative context enhances our understanding of the evolution of aging.

Linear transport infrastructure can alter the viability of populations and wildlife passages are used to mitigate their impacts. The assessment of their outcomes is often limited to recording the use of the tunnels by a focal species. For amphibians, the effectiveness of tunnels is poorly evaluated with little information about whether certain features encourage individuals that may be reluctant to pass through tunnels. One study showed that acoustic enrichment with anuran calls can increase the crossing of tunnels by newts. This study recorded the behavior of three European amphibian species in three tunnels, tracking them with PIT tags and detection with four RFID antennas installed on the floor of the tunnels. We tested (1) the effectiveness of the antennas in detecting the species, (2) the effect of the length of the tunnels, and (3) the effect of acoustic enrichment. Using a multi-state capture–recapture model, we evaluated the probability of an individual advancing between the tunnel sections. The effectiveness of the antennas varied according to species, higher for Urodela species than for Anuran species. Several types of paths were detected (constant and varying speeds, halt, and back-and-forth movements). The fire salamander and the great crested newt individuals exhibited a similar variety of movements in the tunnels (21 and 40 m length). Triturus cristatus made similar movements in the tunnels with and without acoustic enrichment. In water frogs, all the individuals (n = 16) made a complete crossing in the tunnel with enrichment vs. 75% (n = 71) in the tunnel without enrichment. In T. cristatus, the probability of going forward at the entrance of the tunnel was 18% higher with enrichment in one tunnel. No significant effect of acoustic enrichment was observed in two others tunnels for this species. In Pelophylax esculentus, this probability was 78% higher in the tunnel with enrichment. This multi-antenna RFID system was able to provide valuable information on the behavior of these small animals when traversing the tunnels, as well as to test the effectiveness of tunnel features. The findings indicate that acoustic enrichment to attract animals to specific locations holds promise as a new conservation tool.