Biology subjects

Mathevet, R.

Publications and source records attributed to Mathevet, R..

3 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↗

bioRxiv2025

Spatial covariation between wild boars and other mammals in peri-urban landscapes: insights for management from southern France

Global urbanization is rapidly increasing, transforming ecosystems and favoring generalist species that adapt to human-modified environments. The wild boar, a highly adaptable species, is expanding its range and increasingly observed in urban and peri-urban areas, where it can cause accidents, damage, and health concerns. To mitigate their presence, non-lethal control strategies such as vegetation clearing in peri-urban parks and wastelands are being implemented to reduce the number of suitable resting sites. However, the ecological consequences of such habitat modifications on other wildlife species remain poorly understood. This knowledge gap limits the development of effective urban wildlife management strategies that seeks to balance ecological, social and economic considerations without harming wild boar populations and urban ecosystems. In this context, we used camera trapping to study the covariation between wild boars and other mammal species in a peri-urban area, with the aim of guiding targeted and effective management strategies. Here, we show a widespread presence of wild boars but no spatial or temporal covariation between the wild boars and the other species. In contrast, we found strong spatial structuring in mammal communities, primarily driven by small carnivores (mustelids, genets, cats, foxes) and a minimal influence of temporal variation, confirming that spatial factors, rather than seasonal changes, largely shaped species distributions. The study of the temporal variation across months indicated minimal seasonal structuring but revealed substantial within-site variability in month-to-month species abundance, with a general abundance gradient driven by common species like wild boar, cat, and fox. In conclusion, our results show that the lack of spatial covariation between wild boar and other species prevents reliable predictions, supporting a targeted rather than general approach to vegetation management.

ecology↗