Reproduction of the red fox Vulpes vulpes in western France: does staining improve estimation of litter size from placental scar counts?

Ruette, Sandrine; Albaret, Michel

doi:10.1007/s10344-010-0465-y

Cited by 11 publications

(20 citation statements)

References 41 publications

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“…The density of the studied population was estimated at 1.00 adults/km 2 (0.87–1.16) and 0.57 adults/km 2 (0.45–0.71) for the pre‐mange and mange periods, respectively. Although higher densities have been reported for an urban fox population in Bristol (7.8–25.8 adults/km 2 for the pre‐mange period and 0.7–37.0 adults/km 2 for the mange period; Soulsbury et al ), the current estimates agree with other reports of 0.46–1.04 adults/km 2 in Germany (Stubbe ), 0.57–2.76 adults/km 2 in Britain (Heydon et al ), 0.21–2.23 adults/km 2 in Britain (Webbon et al ), 0.9–2.2 adults/km 2 in France (Ruette and Albaret ), and 0.01–2.8 adults/km 2 around the latitude of 45°N in Eurasia (Bartoń and Zalewski ). Therefore, we consider that our analyses yielded reliable estimates.…”

Section: Discussionsupporting

confidence: 83%

“…The average (95% credible interval) of estimated population size in the Nemuro Peninsula was 340.3 (298.8-392.2) for the pre-mange period and 197.6 (148.2-255.4) for the mange period. The mating system of the red fox is basically monogamous (Iossa et al 2008), the average litter size is estimated at around 5 (Stubbe 1980, Harris 1981, Ruette and Albaret 2011, and the mean of observed numbers of cubs at den sites in this study was Table 1. Partial regression coefficient estimates (PRC), standard deviation (SD), and other statistical values of explanatory variables in the generalized linear model for natural mortality [natural morality (year t) $ adult numbers (t) þ culling mortality (t À 1) þ birth rate (t) þ mange (t)] and birth rate [birth rate (t) $ adult numbers (t) þ culling mortality (t À 1) þ natural morality (t À 1) þ mange (t)].…”

Section: Population Estimationmentioning

confidence: 72%

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Demographic analyses of a fox population suffering from sarcoptic mange

et al. 2014

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We reconstructed a red fox population through a cohort analysis based on age-specific numbers of culled individuals between 1987 and 2008, a timeframe that covers the pre-mange and mange periods, and analyzed the impact of sarcoptic mange on the fox population in Nemuro, Japan. In the process of the reconstruction, we estimated annual mortality (caused by natural factors and culling) and birth rates by referring to the annual change in an index of population abundance and the recovery of tagged individuals. The estimated total population size decreased greatly from 303.2 to 70.8 between 1996 and 2000 in the study area (136.5 km 2 ); the first mange-infected individual was found in 1997. The natural mortality estimate (0.613) in 1998 was high, and it was also high in 1997 and 1999 (0.504 and 0.507, respectively), whereas mortality caused by culling did not show any particular change in these years. The birth rate (number of cubs per adult) was high in 1998 and 1999 despite the mange prevalence. Although the infection rate (number of infected individuals per inspected fox) decreased after the peak in 1999, foxes were found infected with mange in every study year between 1997 and 2013, except for 2002. Natural mortality was higher during the mange period (1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008) than during the pre-mange period (1987)(1988)(1989)(1990)(1991)(1992)(1993)(1994)(1995)(1996), whereas we did not detect a significant difference in birth rates between the periods. A generalized linear model analysis showed significant effects of adult density and birth rate on natural mortality together with the effects of mange. We interpreted higher natural mortality in years with higher birth rates as simply a result of the population in those years including more cubs with higher mortality. The positive effect of adult density during the pre-mange period on natural mortality can be explained by competition for territory, whereas high adult density may also have contributed to the spread of mange for the mange period, causing higher mortality. This study shows that the use of cohort analysis can be extended to estimating demographic parameters by referring to external data. Ó 2014 The Wildlife Society.

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Section: Discussionsupporting

confidence: 83%

Section: Population Estimationmentioning

confidence: 72%

Demographic analyses of a fox population suffering from sarcoptic mange

et al. 2014

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“…Uteri horns were opened longitudinally and examined for placental scars (Elmeros et al, 2003;Lindström, 1994). When the evaluation of litter size was questionable, we used a staining method to facilitate the identification of active placental scars (Ruette and Albaret, 2011).…”

Section: Reproductive Parametersmentioning

confidence: 99%

“…with a singular aspect when compared to others from the same uterus or from other uteri at the same period of examination. However it does not permit the distinction of scars that could have persisted from earlier pregnancies from those that have been due to resorption or abortion (Ruette et Albaret, 2011). So, we did not estimate resorption rates from atypical placental scars counts.…”

Section: Reproductive Parametersmentioning

confidence: 99%

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

et al. 2017

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To cite this version:Nicolas Lieury, Nolwenn Drouet-Hoguet, Sandrine Ruette, Sébastien Devillard, Michel Albaret, et al.. Rural populations of the red fox Vulpes vulpes show little evidence of reproductive senescence. Please cite this article as: Lieury, Nicolas, Drouet-Hoguet, Nolwenn, Ruette, Sandrine, Devillard, Sébastien, Albaret, Michel, Millon, Alexandre, Rural populations of the red fox Vulpes vulpes show little evidence of reproductive senescence.Mammalian Biology http://dx.Abstract: 222 Word count: 5561 Figures: 2 Tables: 3Reproductive senescence in the red fox AbstractThe 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 thereafter 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 placental 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.

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

et al. 2015

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Attempts 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. Ó 2015 The Wildlife Society.

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Reproduction of the red fox Vulpes vulpes in western France: does staining improve estimation of litter size from placental scar counts?

Cited by 11 publications

References 41 publications

Demographic analyses of a fox population suffering from sarcoptic mange

Demographic analyses of a fox population suffering from sarcoptic mange

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

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

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