Rural populations of the red fox Vulpes vulpes show little evidence of reproductive senescence

International audienceThe ageing theory predicts fast and early senescence for fast-living species. We investigated whether the pattern of senescence of a medium-sized, fast-living and heavily-culled mammal, the red fox (Vulpes vulpes), fits this theoretical prediction. We used cross-sectional data from a large-scale culling experiment of red fox conducted over six years in five study sites located in two regions of France to explore the age-related variation in reproductive output. We used both placental scars and embryos counts from 755 vixens’ carcasses aged by the tooth cementum method (age range : 1-10) , as proxies for litter size. Mean litter size per vixen was 4.7 ± 1.4. Results from Generalized Additive Mixed Models revealed a significant variation of litter size with age. Litter size peaked at age 4 with 5. 0 ± 0.2 placental scars and decreased there after by 0.5 cubs per year. Interestingly, we found a different age-specific variation when counting embryos which reached a plateau at age 5-6 (5.5 ± 0.2)and decreased slower than placent al scars across older ages, pointing out embryo resorption as a potential physiological mechanism of reproductive senescence in the red fox. Contrary to our expectation, reproductive senescence is weak, occurs late in life and takes place at an age reached by less than 11.7% of the population such that very few females exhibit senescence in these heavily culled populations

Genetic integrity of European wildcats: Variation across biomes mandates geographically tailored conservation strategies

Hybridisation between domestic and wild taxa can pose severe threats to wildlife conservation, and human-induced hybridisation, often linked to species' introductions and habitat degradation, may promote reproductive opportunities between species for which natural interbreeding would be highly unlikely. Using a biome-specific approach, we examine the effects of a suite of ecological drivers on the European wildcat's genetic integrity, while assessing the role played by protected areas in this process. We used genotype data from 1217 putative European wildcat samples from 13 European countries to assess the effects of landcover, disturbance and legal landscape protection on the European wildcat's genetic integrity across European biomes, through generalised linear models within a Bayesian framework. Overall, we found European wildcats to have genetic integrity levels above the wildcat-hybrid threshold (ca. 83%; threshold = 80%). However, Mediterranean and Temperate Insular biomes (i.e., Scotland) revealed lower levels, with 74% and 46% expected genetic integrity, respectively. We found that different drivers shape the level of genetic introgression across biomes, although forest integrity seems to be a common factor promoting European wildcat genetic integrity. Wildcat genetic integrity remains high, regardless of landscape legal protection, in biomes where populations appear to be healthy and show recent local range expansions. However, in biomes more susceptible to hybridisation, even protected areas show limited effectiveness in mitigating this threat. In the face of the detected patterns, we recommend that species conservation and management plans should be biome- and landscape-context-specific to ensure effective wildcat conservation, especially in the Mediterranean and Temperate Insular biomes.Thanks are due to FCT/MCTES for the financial support to cE3c (UIDB/00329/2020), through national funds, and the co-funding by the FEDER, within the PT2020 Partnership Agreement and Compete 2020. PM was supported by UID/BIA/50027/2021 with funding from FCT/MCTES through national funds. FDR was supported by a postdoctoral contract from the University of Málaga (I Plan Propio de Investigación y Transferencia, call 2020). This study was partly funded by research projects CGL2009-10741, funded by the Spanish Ministry of Science and Innovation and EU-FEDER, and OAPN 352/2011, funded by the Organismo Autónomo Parques Nacionales (Spain). Luxembourg sample collection has been co-funded by the Ministry of Environment, Climate and Sustainable Development of Luxembourg. We would like to thank the Bavarian Forest National Park Administration for the approval and support in collecting samples.Peer reviewe

Les données écologiques disponibles dans le cadre de la procédure de classement des espèces d’animaux susceptibles d’occasionner des dégâts

La démarche réglementaire concernant la procédure de classement des espèces d’animaux susceptibles d’occasionner des dégâts (anciennement animaux susceptibles d’être classés nuisibles) a beaucoup évolué au cours de ces vingt dernières années et nécessite maintenant de justifier ce classement par des critères techniques qui, au fil du temps, ont été précisés par la jurisprudence. À première vue, certains de ces critères peuvent être construits sur la base des connaissances en écologie et en bi..

Altitude shapes the environmental drivers of large‐scale variation in abundance of a widespread mammal species

International audienc

Estimation of Bait Uptake by Badgers, Using Non-invasive Methods, in the Perspective of Oral Vaccination Against Bovine Tuberculosis in a French Infected Area

International audienceAlthough France is officially declared free of bovine tuberculosis (TB), Mycobacterium bovis infection is still observed in several regions in cattle and wildlife, including badgers ( Meles meles ). In this context, vaccinating badgers should be considered as a promising strategy for the reduction in M. bovis transmission between badgers and other species, and cattle in particular. An oral vaccine consisting of live Bacille Calmette–Guérin (BCG) contained in bait is currently under assessment for badgers, for which testing bait deployment in the field and assessing bait uptake by badgers are required. This study aimed to evaluate the bait uptake by badgers and determine the main factors influencing uptake in a TB-infected area in Burgundy, north-eastern France. The baits were delivered at 15 different setts located in the vicinity of 13 pastures within a TB-infected area, which has been subject to intense badger culling over the last decade. Pre-baits followed by baits containing a biomarker (Rhodamine B; no BCG vaccine) were delivered down sett entrances in the spring (8 days of pre-baiting and 4 days of baiting) and summer (2 days of pre-baiting and 2 days of baiting) of 2018. The consumption of the marked baits was assessed by detecting fluorescence, produced by Rhodamine B, in hair collected in hair traps positioned at the setts and on the margins of the targeted pastures. Collected hairs were also genotyped to differentiate individuals using 24 microsatellites markers and one sex marker. Bait uptake was estimated as the proportion of badgers consuming baits marked by the biomarker over all the sampled animals (individual level), per badger social group, and per targeted pasture. We found a bait uptake of 52.4% (43 marked individuals of 82 genetically identified) at the individual level and a mean of 48.9 and 50.6% at the social group and pasture levels, respectively. The bait uptake was positively associated with the presence of cubs (social group level) and negatively influenced by the intensity of previous trapping (social group and pasture levels). This study is the first conducted in France on bait deployment in a badger population of intermediate density after several years of intensive culling. The results are expected to provide valuable information toward a realistic deployment of oral vaccine baits to control TB in badger populations

Analysis of a multi-type resurgence of Mycobacterium bovis in cattle and badgers in Southwest France, 2007-2019

Abstract Although control measures to tackle bovine tuberculosis (bTB) in cattle have been successful in many parts of Europe, this disease has not been eradicated in areas where Mycobacterium bovis circulates in multi-host systems. Here we analyzed the resurgence of 11 M. bovis genotypes (defined based on spoligotyping and MIRU-VNTR) detected in 141 farms between 2007 and 2019, in an area of Southwestern France where wildlife infection was also detected from 2012 in 65 badgers. We used a spatially-explicit model to reconstruct the simultaneous diffusion of the 11 genotypes in cattle farms and badger populations. Effective reproduction number R was estimated to be 1.34 in 2007–2011 indicating a self-sustained M. bovis transmission by a maintenance community although within-species Rs were both < 1, indicating that neither cattle nor badger populations acted as separate reservoir hosts. From 2012, control measures were implemented, and we observed a decrease of R below 1. Spatial contrasts of the basic reproduction ratio suggested that local field conditions may favor (or penalize) local spread of bTB upon introduction into a new farm. Calculation of generation time distributions showed that the spread of M. bovis has been more rapid from cattle farms (0.5–0.7 year) than from badger groups (1.3–2.4 years). Although eradication of bTB appears possible in the study area (since R < 1), the model suggests it is a long-term prospect, because of the prolonged persistence of infection in badger groups (2.9–5.7 years). Supplementary tools and efforts to better control bTB infection in badgers (including vaccination for instance) appear necessary

Isotopic evidence of individual specialization toward free-ranging chickens in a rural population of red foxes

International audienc

Compensatory immigration challenges predator control: An experimental evidence-based approach improves management

International audienceAttempts to control predator numbers through spatially restricted culling typically faces a compensation process via immigration from surrounding source populations. To extend control effort to avoid this issue is in most instances impractical, both logistically and financially. Evidence-based strategy is therefore required to improve management practices. In close collaboration with local managers and hunters, we manipulated culling effort on red fox (Vulpes vulpes) over 5-6 years in 5 areas measuring 246 AE 53 km 2. We estimated fox density in late February each year by spotlight counts with distance sampling and estimated reproductive performance by post-mortem examination of culled foxes. We then used mixed modeling to assess how culling rate (defined as foxes killed/foxes available) affected fox population growth from year to year, accounting for compensatory feedbacks. We found a strong compensatory density feedback acting through immigration, allowing red fox populations to resist high culling rates. Culling appeared ineffective at reducing late winter densities to below 25-32% of the estimated carrying capacity. On average, an annual culling rate equivalent to about 45% of the pre-breeding population was required to maintain density at 1 fox/ km 2 , given a carrying capacity of 1.5 foxes/km 2 , although there was considerable variation among sites. The required culling rate dropped to 25% if the culling could be performed during winter, after the fox dispersal period. In contrast, culling during the pre-dispersal breeding period was totally compensated for through immigration by the following February. Concentrating culling during the winter could improve the ability of practitioners to control year-to-year trends in fox numbers, taking into account site-specific carrying capacity. A winter strategy would also reduce the number of animals killed and hence the ethical and logistical costs of fox control, given limited financial and human resources. Our study illustrates how collaboration between local practitioners and scientists can make large-scale replicated management experiments achievable, leading to mutually approved guidelines