The effects of induced sterility on the territorial behaviour and survival of foxes

Saunders, Glen; McIlroy, John; Berghout, Mani; Kay, Barry J.; Gifford, E. J.; Perry, Rob; Ven, Remy van de

doi:10.1046/j.1365-2664.2002.00696.x

Cited by 69 publications

(31 citation statements)

References 49 publications

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“…PZP-based immunocontraceptives increased lifespan and body conditions of mares Kirkpatrick and Turner 2007), tubal ligation increased survival in rabbits (Twigg et al 2000;Williams et al 2007) and GonaCon improved body condition of deer (Gionfriddo et al 2011b). Conversely, Saunders et al (2002) observed no differences in survival, dispersal or territory size of surgically sterilised foxes compared with fertile foxes, although sterilised vixens were more likely than fertile females to share their territories with each other.…”

Section: Fertility-control Impact On Wildlife Populationsmentioning

confidence: 50%

Fertility control to mitigate human–wildlife conflicts: a review

2014

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Abstract. As human populations grow, conflicts with wildlife increase. Concurrently, concerns about the welfare, safety and environmental impacts of conventional lethal methods of wildlife management restrict the options available for conflict mitigation. In parallel, there is increasing interest in using fertility control to manage wildlife. The present review aimed at analysing trends in research on fertility control for wildlife, illustrating developments in fertility-control technologies and delivery methods of fertility-control agents, summarising the conclusions of empirical and theoretical studies of fertility control applied at the population level and offering criteria to guide decisions regarding the suitability of fertility control to mitigate human-wildlife conflicts. The review highlighted a growing interest in fertility control for wildlife, underpinned by increasing numbers of scientific studies. Most current practical applications of fertility control for wild mammals use injectable single-dose immunocontraceptive vaccines mainly aimed at sterilising females, although many of these vaccines are not yet commercially available. One oral avian contraceptive, nicarbazin, is commercially available in some countries. Potential new methods of remote contraceptive delivery include bacterial ghosts, virus-like particles and genetically modified transmissible and non-transmissible organisms, although none of these have yet progressed to field testing. In parallel, new species-specific delivery systems have been developed. The results of population-level studies of fertility control indicated that this approach may increase survival and affect social and spatial behaviour of treated animals, although the effects are species-and context-specific. The present studies suggested that a substantial initial effort is generally required to reduce population growth if fertility control is the sole wildlife management method. However, several empirical and field studies have demonstrated that fertility control, particularly of isolated populations, can be successfully used to limit population growth and reduce human-wildlife conflicts. In parallel, there is growing recognition of the possible synergy between fertility control and disease vaccination to optimise the maintenance of herd immunity in the management of wildlife diseases. The review provides a decision tree that can be used to determine whether fertility control should be employed to resolve specific human-wildlife conflicts. These criteria encompass public consultation, considerations about animal welfare and feasibility, evaluation of population responses, costs and sustainability.

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Section: Fertility-control Impact On Wildlife Populationsmentioning

confidence: 50%

Fertility control to mitigate human–wildlife conflicts: a review

2014

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“…Their position in the top of the food webs and their large potential impact on different human activities (game, agriculture, etc..., Saunders et al 1995;Reynolds. and Tapper 1996;Moore et al 1999) make this group especially significant in conservation and management actions.…”

Section: Introductionmentioning

confidence: 99%

Surveying carnivores at large spatial scales: a comparison of four broad-applied methods

Virgós²,

et al. 2006

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Reliable methods to estimate species richness are very important to managers and conservationists because they provide key data to make the right decisions in conservation programmes. In the case of carnivore mammals, traditional methods, such as direct count censuses, are not useful since these animals are usually scarce, elusive and nocturnal. Difficulties in carnivore sampling are compounded when monitoring programmes are developed at large spatial scales, where high economic costs and field efforts are necessary to achieve reliable richness or abundance estimates. These problems have highlighted the need to find more effective carnivore survey methods, especially in regions with high rates of landscape change, such as the Mediterranean basin. The present study, performed in a typical Mediterranean area, was the first in Europe to test simultaneously the relative efficiencies of four broad-applied sampling methods to detect carnivore species at large spatial scales. Sign surveys based on scat detection, scent stations, camera-trapping and livetrapping were investigated. We compared efficiencies using biological parameters and by considering both the logistic and economic costs of each method. Overall, scent stations and sign surveys were the most efficient methods both in economic and logistic terms. In addition, the use of scent stations may be necessary to detect

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“…Evaluating the long-term effectiveness of a contraceptive is needed to predict the effects of fertility control, in terms of proportion of infertile animals and longevity of effect, on population size. For territorial or hierarchically structured species, contraception-induced changes in social behaviour, such as decreased aggressiveness, could lead to disruption of social hierarchies and spacing behaviour and, in turn, affect the impact of fertility control on a population (Saunders et al 2002;Crawford et al 2011). The potential impact of a contraceptive on social behaviour should thus be evaluated before fertility control is used to manage wildlife populations.…”

Section: Introductionmentioning

confidence: 99%

Long-term effects of immunocontraception on wild boar fertility, physiology and behaviour

et al. 2012

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Context. Fertility control appears as a publicly acceptable alternative to lethal methods for limiting population growth in wildlife. Recently developed single-dose immunocontraceptive vaccines have induced infertility in several mammals. However, the potential side-effects and the long-term effectiveness of these contraceptives have been poorly investigated.Aims. We tested the long-term effectiveness and potential side-effects of the single-dose gonadotrophin-releasing hormone (GnRH) vaccine GonaConÔ on captive female wild boar.Methods. We carried out two sequential trials: Trial 1 (n = 6 GonaConÔ-treated and 6 control wild boar) and Trial 2 which started two years later and replicated Trial 1. We assessed the effectiveness of GonaConÔ to cause infertility by measuring GnRH antibody titres, by monitoring the oestrous cycle through the concentration of faecal progesterone and by recording the sows' reproductive output in the 4-6 years following treatment. We evaluated the potential side-effects by monitoring behaviour, bodyweight and haematological and biochemical variables.Key results. GnRH-antibody titres decreased with time but were still detectable in all females six years after vaccination with a single dose of GonaConÔ. In Trial 1 none of the treated females gave birth in the six years after vaccination. In Trial 2, progesterone indicated that two of the six treated females were cycling. One of the cycling treated females gave birth one year after vaccination; the other five, including the second cycling sow, did not reproduce in the four years following vaccination. We found no differences in bodyweight, haematology, biochemistry and behaviour and no obvious sign of injection site reaction.Conclusions. GonaConÔ can suppress reproduction in wild boar with no long-term effects on behaviour and physiology. Therefore, GonaConÔ can be regarded as an effective and safe contraceptive for this species.Implications. The lack of evidence of adverse effects and the longevity of effect of GonaConÔ suggest that this contraceptive could be now tested in field trials and in contexts where culling of overabundant populations of wild boar is unfeasible, illegal or unacceptable. These instances include urban areas, parks, and management of diseases where culling might cause social perturbation and result in increased disease transmission rates.

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The effects of induced sterility on the territorial behaviour and survival of foxes

Cited by 69 publications

References 49 publications

Fertility control to mitigate human–wildlife conflicts: a review

Fertility control to mitigate human–wildlife conflicts: a review

Surveying carnivores at large spatial scales: a comparison of four broad-applied methods

Long-term effects of immunocontraception on wild boar fertility, physiology and behaviour

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