Biology subjects

Miaud, C.

Publications and source records attributed to Miaud, C..

6 recordsLinked to original sources

bioRxiv2026

Environmental DNA enables rapid detection of invasive coypu and complements camera trapping

Effective management of invasive species requires surveillance methods that reliably detect populations while minimizing field effort. Environmental DNA (eDNA) offers a potentially rapid alternative to conventional monitoring, but direct comparisons with other non-invasive methods remain limited for invasive mammals. Here, we compared eDNA water sampling and camera trapping for detecting established populations of coypu (Myocastor coypus), an invasive semi-aquatic rodent. Using replicated data collected across Mediterranean river systems in southern France, we estimated detection probabilities conditional on coypu presence using Bayesian generalized linear mixed models and quantified the sampling effort required to achieve high cumulative detection probability. Detection probability was 93.0% (95% credible interval: 72.1-98.9%) for a single eDNA water sample, compared with 52.8% (22.6-91.1%) for 30 camera-trap days, with a 96.9% posterior probability that eDNA detection was higher. Two eDNA samples were sufficient to achieve a median cumulative detection probability above 95%, compared with four 30-day camera-trapping periods. Detection also varied at different spatial scales, with camera-trap detectability being heterogeneous among local camera locations and eDNA detectability varying more among catchments. These results show that eDNA provides a rapid and reliable approach for confirming the presence of established coypu populations, while camera traps provide complementary information on activity, behaviour and habitat use. Combining rapid eDNA screening with targeted camera trapping may therefore provide an efficient surveillance strategy for invasive semi-aquatic mammals.

ecology↗

bioRxiv2026

Comparative efficiency of eDNA, camera traps and scat surveys to detect a semi-aquatic mammal across multiple catchments

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.

ecology↗

bioRxiv2026

Effectiveness and efficiency of temporary fences as mitigation measures for preventing amphibians roadkill

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.

ecology↗

bioRxiv2024

Improving the monitoring of the invasive Blue Crab (Callinectes sapidus): combining environmental DNA and citizen observations

O_LIEarly detection is a crucial tool for identifying the spread of invasive species. C_LIO_LIIn 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. C_LIO_LIA 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 Callinectes sapidus along the Occitanie coastline (Western Mediterranean, France). C_LIO_LIUsing eDNA probe-based qPCR, Callinectes sapidus was detected in 32 out 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. C_LIO_LIOur results demonstrate the utility of eDNA probe-based qPCR for effective monitoring 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. C_LI

ecology↗

bioRxiv2019

Slow life-history strategies are associated with negligible actuarial senescence in western Palearctic salamanders

Actuarial senescence (hereafter \"senescence\") has been viewed for a long time as an inevitable and uniform process. However, the work on senescence has mainly focused on endotherms (especially mammals) with deterministic growth and low regeneration capacity at adult stages, leading to a strong taxonomic bias in the study of aging. Recent studies have highlighted that senescence could indeed display highly variable trajectory shape that correlates with species life history traits. Slow life histories and indeterminate growth seem to be associated with weak and late senescence. Furthermore, a few studies have suggested that high regenerative abilities could make senescence negligible in several ectotherms (e.g., hydra and salamanders). However, demographic data for species that would allow testing of these hypotheses are scarce and fragmented. Here, we investigated senescence patterns in a group of salamanders (i.e. \"true salamanders\") from the Western Palearctic using capture-recapture data and Bayesian modeling. Our results showed that salamanders have slow life histories and that they experience negligible senescence. This pattern was consistent at both intra- and interspecific levels, suggesting that the absence of senescence may be a phylogenetically conserved trait. The regenerative capacities of true salamanders, and urodeles in general, likely explains why these small ectotherms have lifespans similar to that of large endotherms (e.g., ungulates, large birds) and undergo negligible senescence contrary to most amniotes including humans. Our study seriously challenges the idea that senescence is a ubiquitous phenomenon in the living world.

ecology↗

bioRxiv2018

Development and worldwide use of a non-lethal and minimal population-level impact protocols for the isolation of chytrids from amphibians

Parasitic chytrid fungi have emerged as a significant threat to amphibian species worldwide, necessitating the development of techniques to isolate these pathogens into sterile culture for research purposes. However, early methods of isolating chytrids from their hosts relied on killing amphibians. We modified a pre-existing protocol for isolating chytrids from infected animals to use toe clips and biopsies from toe webbing rather than euthanizing hosts, and distributed the protocol to interested researchers worldwide as part of the BiodivERsA project RACE - here called the RML protocol. In tandem, we developed a lethal procedure for isolating chytrids from tadpole mouthparts. Reviewing a database of use a decade after their inception, we find that these methods have been widely applied across at least 5 continents, 23 countries and in 62 amphibian species, and have been successfully used to isolate chytrids in remote field locations. Isolation of chytrids by the non-lethal RML protocol occured in 18% of attempts with 207 fungal isolates and three species of chytrid being recovered. Isolation of chytrids from tadpoles occured in 43% of attempts with 334 fungal isolates of one species (Batrachochytrium dendrobatidis) being recovered. Together, these methods have resulted in a significant reduction and refinement of our use of threatened amphibian species and have improved our ability to work with this important group of emerging fungal pathogens.

ecology↗