European Wild Rabbit Oryctolagus Cuniculus Research Articles

QUARANTINE LENGTH AND SURVIVAL OF TRANSLOCATED EUROPEAN WILD RABBITS

Abstract European wild rabbits (Oryctolagus cuniculus) are frequently translocated for hunting and conservation purposes. Quarantining these animals prior to release reduces the risk of releasing rabbits incubating field infections of myxomatosis or viral haemorrhagic disease (RHD), and it provides a way to vaccinate these animals against both diseases. However the optimal quarantine period needed to achieve these goals is not known. We therefore assessed the effects of quarantine lengths (2, 4, 6, 8 weeks) on rabbit biochemical parameters, immunity induced by vaccination against myxomatosis and RHD, and survival of translocated rabbits. We found that levels of total bilirubin, urea nitrogen, aspartate aminotransferase (AST), and alanine aminotransferase (ALT) enzymatic activities were significantly (P < 0.05) decreased during quarantine, independent of quarantine length, whereas hematocrit levels increased significantly. All pregnant female rabbits aborted or lost litters during quarantine. Seroconversio...

Conservation of European wild rabbit populations when hunting is age and sex selective

Several predator species at risk of extinction in Southwestern Europe are dependent on the population density of European wild rabbits Oryctolagus cuniculus. Rabbit populations in the region, however, have recently undergone dramatic decreases in population density, which may be exacerbated by hunting. Current hunting policies set the autumn–winter season, just before the start of rabbit reproduction, as the main hunting season, and previous theoretical models have estimated that the current hunting season may have the greatest negative impact on rabbit abundance and should be changed. We utilised a model for rabbit population dynamics to determine the effects of the timing of hunting during two seasons, summer and autumn, on the tendency of rabbit populations to be over-harvested and on the number of rabbits hunted. This model included field estimates of age- and sex-selection biases of hunting by shotgun. Scenarios with different hunting rates and sex- and age-selection probabilities of hunting were simulated for populations with different turnover levels and with and without compensatory mortality mechanisms. Field estimations showed that hunting in summer was juvenile-biased whereas autumn hunting was juvenile- and male-biased. In contrast to previous findings, our modelling results suggested that hunting in autumn may be the most conservative option for harvesting of rabbit populations, since these populations were more prone to be over-harvested during the summer. The differences between the two seasons in number of rabbits hunted were dependent on population dynamics and hunting sex- and age-selection probabilities. Our findings suggest that altering of current hunting policies would not optimise the exploitation or conservation of wild rabbit populations, but that the latter may be improved by some changes in the timing of hunting.

Short-term survival and dispersal of translocated European wild rabbits. Improving the release protocol

Translocation of European wild rabbit Oryctolagus cuniculus L. is one of the most frequent management tools to increase rabbit density in Spain, both as prey of several predators that are threatened with extinction and for sport hunting. Nevertheless the elevated short-term mortality by predation makes translocations unsuccessful and increases their biological cost. Information on the factors affecting the short-term survival and dispersal of translocated rabbits is required to improve release management and increase performance of translocated rabbits, and to avoid the use of non-selective lethal methods for predator control. In this study we tested electric fencing and night-shooting as alternative to traditional release protocols, and the effects of vegetation cover and warren fencing on short-term survival and dispersal of rabbits. Night shooting performed during the first nights after release increased significantly the survival of rabbits, by hindering the activity of carnivores in the release area. The use of an electric fence enclosure also increased the performance of rabbits, but was not efficient to constraint rabbit dispersal. Rabbits released in areas with low vegetation cover showed higher mortality and dispersal distances than rabbits released in high cover areas. Warren fencing decreased both the dispersal of rabbits and the adverse impact of predation in low cover areas, but had no effect in high cover areas. Selection of high cover areas or warren fencing in low cover areas seem to be the most advantageous release conditions to decrease the short-term predation impact, reducing the biological cost of rabbit translocations and the risks for endangered predators derived from the use of traditional predator control practices during translocations.

Applicability of rabbit microsatellite primers for studies of hybridisation between an introduced and a native hare species.

Introduced species may hybridise with relatives in the native fauna or flora and thereby compete for matings and transmit alien DNA. Such interference may contaminate unique genepools, disturb existing ecological balances and may ultimately result in the extinction of the native species. In Sweden, the introduced brown hare (Lepus europaeus Pall.) hybridise with the native mountain hare (L. timidus L.), both relatively common members of the present Swedish fauna. This hybridisation has resulted in the transmission of mitochondrial DNA from the mountain hare to the brown hare, but absence of species differences in karyotype and allozymes have prevented investigations of the amount of nuclear gene flow. More polymorphic genetic markers are needed to analyse evidence of hybridisation in the nuclear genome. The conservation of microsatellite loci across taxa usually enables PCR amplification of microsatellites in closely related species with the same primers. We have used five microsatellite primer pairs, developed for the European wild rabbit (Oryctolagus cuniculus L.) to amplify microsatellites in the two species of hare in Sweden. The obtained allelic variation was used to construct a genetic distance tree based on the amount of shared alleles between all pairs of individuals (shared-allele index). This method offered sufficient differences to arrange all individuals in two groups, one for each species. Identification of individual hybrids based on the number of alleles shared between the species is not possible with these five microsatellite markers.

Influence of herbaceous cover, shelter and land cover structure on wild rabbit abundance in NW Portugal

The European wild rabbitOryctolagus cuniculus (Linnaeus, 1758) populations in the Iberian Peninsula has suffered a serious decline. Therefore, the knowledge about the factors that influence rabbit distribution and abundance is of major interest for conservation and management programmes. Rabbit relative abundance was evaluated by pellet counting in relation to herbaceous ground cover, shelter availability (tall scrub cover and gaps in rocks) and land cover structure in the Peneda-Gerês National Park (PGNP), NW Portugal. Rabbit abundance was higher at intermediate levels of herbaceous cover, but no significant statistical differences were detected. A strong association between the abundance index and tall scrub cover was verified, and when this cover was rare, an association with gaps in rocks was observed. At the land cover level, rabbit abundance was associated with high interspersion sites of rocks with matorral and high interspersion sites of tall scrubland. Evidence from this study highlighted the importance of shelter and the interspersion of open/shelter habitats for rabbits. This pattern could be interpreted as an anti-predator strategy. Therefore, management actions should favour the growing and establishing of tall scrub patches and the selective cutting in highly continuous areas of tall scrub vegetation.

SHORT-TERM NEGATIVE EFFECTS OF VACCINATION CAMPAIGNS AGAINST MYXOMATOSIS AND VIRAL HEMORRHAGIC DISEASE (VHD) ON THE SURVIVAL OF EUROPEAN WILD RABBITS

The capture and handling of live European wild rabbits (Oryctolagus cuniculus) are unavoidable initial steps for immunization by vaccination against viral hemorrhagic disease (VHD) and myxomatosis as a management tool aimed at enhancing wild rabbit populations. We investigated the short-term effects of vaccination campaigns against VHD and myxomatosis on the survival of 206 European wild rabbits in a Spanish population. While no effect was observed on the survival of adult rabbits, young and subadult rabbits (P < 0.001) had higher mortality rates during the first week after handling than in the subsequent 3 weeks. The hazard rate of death from disease was inversely correlated with body condition (P < 0.001) during the first week. Vaccination increased the hazard rate of death due to disease during the first 7 days post-handling, although this detrimental effect was higher in young rabbits (P = 0.012) and modulated by body condition (P = 0.004). The hazard rate of dying from predation during the first week was higher for males than females (P = 0.023) and in subadults compared to young rabbits (P = 0.004). Body condition was inversely related to the predation hazard rate (P = 0.002). Our results suggest that vaccination campaigns had a short-term negative impact caused by the stress of handling in addition to the detrimental effects of vaccination against VHD and myxomatosis. Future studies should consider this negative impact to assess the true efficacy of vaccination campaigns in wild populations.

Habitat factors related to wild rabbit conservation in an agricultural landscape

Populations of European wild rabbit (Oryctolagus cuniculus) have been decreasing since the 1950s. Changes in agricultural practices have been suggested as reasons for their decline in Mediterranean landscapes. We evaluated the environmental variables affecting rabbit distribution in a semiarid agricultural landscape of Northeastern Spain. Sampling was performed in 147 sites randomly distributed across Zaragoza province. At each site, data were recorded in five 100 m segments along a 1 km transect, following ecotones between crops and natural-vegetation areas. A rabbit abundance index was estimated from latrine count, pellet density and number of plots with pellets. In addition to environmental variables that have been shown to be related to rabbit abundance in other habitats, as climate, soil hardness and topography of the site, we measured landscape components related to agricultural use, such as structure of natural vegetation in remaining areas non-devoted to agricultural use and distances to different types of crops and to ecotone between crop and natural vegetation. Our results showed that rabbit abundance was positively correlated to yearly mean temperature, February and May mean rainfall, and negatively correlated to September and November mean rainfall, hardness of soil, and site topography. In relation to agricultural use, rabbit abundance was positively correlated to the scrub structure of natural-vegetation areas and negatively correlated to distance to edge between cultivated unirrigated cereal crops (wheat or barley) and yearly resting cereal crops. Rabbit abundance increased only when the edge between alternate cereal crops was less than 50 m from the ecotone between crops and natural vegetation.

Effect of vegetation type and environmental factors on European wild rabbitOryctolagus cuniculus counts in a southern Portuguese montado

This study assesses the effect of vegetation and variables related to weather and light conditions on the efficacy of rabbitOryctolagus cuniculus (Linnaeus, 1758) counts carried out in the south of Portugal. Counts were carried out in two years using driven line transects, and correlated with vegetation type and the variables using generalised linear models. The offset was a surveyed area estimated using Distance Sampling Theory as a means of correcting for detectability bias. More rabbits were observed in dense vegetation during day-time counts and in crops during night-time counts. In 1998, day-time counts were higher with higher average daily temperatures, whilst the night-time counts were higher with higher minimum daily temperatures. In 1999, day-time counts decreased with the amount of rainfall in the previous month, and the night-time counts decreased with the accumulated rainfall in the previous two months and with the higher wind speeds. In order to increase efficacy, counts should be carried out either at dawn or at dusk during the post-breeding season, and with greater intensity in dense scrub or open vegetation with high tree cover. During the breeding season and winter, counts should be carried out after dusk and with greater intensity in arable crops.

Modelling hunting strategies for the conservation of wild rabbit populations

Recently, European wild rabbit ( Oryctolagus cuniculus) populations have undergone a sharp decline that may be exacerbated by hunting. We investigate the effects of the timing of hunting on the conservation of wild rabbit using a model for rabbit population dynamics. Scenarios with different hunting rates and age strategies were simulated for different population qualities. We interviewed hunters to ascertain the degree to which they would accept a change in the timing of hunting. We also investigated the hunting pressure applied by hunters and its relationship with rabbit abundance. Modelling results indicate that the current hunting season has the greatest impact on rabbit abundance. Hunting in late spring optimises hunting extraction while conserving rabbit populations. When the rabbit population quality is low the effects of age strategies and the timing of hunting are less important than the effect of the hunting rate applied. Almost half the hunters would agree to policy changes. More than 75% of hunters implemented self-imposed hunting restrictions to improve rabbit populations, that were more frequently applied in high rabbit abundance areas. Therefore, changing the timing of hunting and increasing the participation of hunters in low abundance areas could optimise both the exploitation and the conservation of wild rabbit populations in southwestern Europe.

Warren building by European rabbits (Oryctolagus cuniculus) in relation to cover availability in a sandy area

AbstractWarrens of the wild European rabbit Oryctolagus cuniculus are of concern in the Iberian Peninsula as a way to recover rabbit populations. However, there are no studies on the selection of sites where rabbits build their warrens. Between 1995 and 1997, in addition to warren size (number of entrances), the vegetation characteristics and the occurrence of tree roots in the ground surface occupied by warren entrances in Mediterranean scrubland and pastureland habitats were recorded in a sandy area of the Doñana National Park. Pastureland warrens were about twice as large as warrens in Mediterranean scrubland, and 1.8–1.4 times larger in the first study year than in the other 2 years. Warrens in pastureland were built more between tree roots (13.3–17.8%) than those built in Mediterranean scrubland (0.7–1.8%). In Mediterranean scrubland, most of the ground surface occupied by warren entrances was under tall shrubs (79.7–87.9%), with some under short shrubs (4.5–7.4%). In pastureland, these figures were 2.0–3.8% for tall shrubs, and 17.2–19.8% for short shrubs. Warrens were built between tree roots significantly less than expected in the Mediterranean scrubland, and slightly more than expected in the pastureland. Whereas warren surface was occupied by short shrubs significantly less than expected in the Mediterranean scrubland, the opposite pattern occurred in the pastureland; however, in both habitats tall shrubs were significantly preferred. These results suggest that rabbits may seek protection against collapsing warrens by selecting sites with some supporting structures such as the roots of trees or shrubs. Scrubland vegetation (preferably tall shrubs) should be favoured for medium‐ and long‐term habitat management of areas aimed at supporting large rabbit populations. Furthermore, in sandy areas, some kind of stable ground support and external protection should be provided when creating artificial warrens for rabbits.

An individual-based model of rabbit viral haemorrhagic disease in European wild rabbits ( Oryctolagus cuniculus)

We developed an individual-based model of Rabbit Viral Hemorrhagic Disease (RVHD) for European wild rabbits ( Oryctolagus cuniculus L.), representing up to 1000 rabbits in four hectares. Model output for productivity and recruitment matched published values. The disease was density-dependent and virulence affected outcome. Strains that caused death after several days produced greater overall mortality than strains in which rabbits either died or recovered very quickly. Disease effect also depended on time of year. We also elaborated a larger scale model representing 25 km 2 and 100,000+ rabbits, split into a number of grid-squares. This was a more traditional model that did not represent individual rabbits, but employed a system of dynamic equations for each grid-square. Disease spread depended on probability of transmission between neighboring grid-squares. Potential recovery from a major population crash caused by the disease relied on disease virulence and frequency of recurrence. The model's dependence on probability of disease transmission between grid-squares suggests the way that the model represents the spatial distribution of the population affects simulation. Although data on RVHD in Europe are lacking, our models provide a basis for describing the disease in realistic detail and for assessing influence of various social and spatial factors on spread.

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Summary19. Neuroinflammatory circuits in Alzheimer's disease: Interleukin-1 induces cyclooxygenase 2 in human neuroblastoma cells20. Neuroinflammatory circuits in Alzheimer's disease: Prostaglandin E-2 induces astroglial interleukin-6 synthesis independent of cAMP formation21. Autonomic dysfunction in patients with multiple sclerosis and fatigue22. Behaviorally conditioned immunosuppression23. Influence of stress on immune-competent cells in patients suffering from ulcerative colitis24. Fatigue and regulation of the hypothalamo-pituitary-adrenal axis (HPA axis) in multiple sclerosis (MS)25. Magnocellular hypothalamic neurohypophysial system under acute inflammation26. Diurnal variations of interleukin 6 plasma levels during sleep and wakefulness: Effects of particularities of blood drawing27. Orgasm-induced circulation of lymphocyte subsets28. Bronchodilatation by antidepressants in allergen sensitized guinea pigs29. Adrenergic modulation of cytokine production during MOG-induced EAE30. The suppressive effect of acetylcholine on monocyte activation is mediated by nicotinergic receptors31. G protein coupled receptors and neuroendocrine signalling in autoimmunity32. Local immune response in the spleen: Regulation by the nervous system and effects on behavior33. The critical first year in the life of European wild rabbits (Oryctolagus cuniculus)34. SLE and RA patients differ from healthy controls in their cytokine pattern after stress exposure35. Stress-induced increment on bronchoalveolar cell count in OVA-sensitized mice is mediated by tachykinin NK1 receptor36. Quantitative analysis of cytokine mRNA expression patterns in the disease course of adolescent patients with anorexia nervosa37. CD26 mutant rats: A model for psycho-neuro-immune interactions38. Failure of α-melanocyte stimulating hormone to attenuate cerebral complications in experimental pneumococcal meningitis39. Neuronal plasticity is mediated by neurotrophin receptor p75NTR in a murine model of allergic bronchial asthma

Improving translocation success: an experimental study of anti‐stress treatment and release method for wild rabbits

AbstractTranslocation is an important tool in conservation biology. However, translocation success is generally low for numerous animal species, therefore experiments are required for improvement. We carried out an experimental translocation of European wild rabbits (Oryctolagus cuniculus). The results may be of great interest for conservation biology, although we used a common species. As rabbits are known to experience a high mortality during the first days following release, it was necessary to assess the influence of handling trauma and environment novelty, respectively, and ways of suppressing them. Both tranquillization treatment during handling and a ‘soft’ release protocol (acclimatization pens in the new territory) were tested. Tranquillization did not increase survival, while the effect of acclimatization depended on sex. Females survived better when acclimatized, while males showed the opposite tendency. This difference is discussed in terms of sex‐specific social behaviour, which is possibly an important correlate of translocation success. Finally, environmental stress seemed to override handling stress in determining the level of early survival for translocated wild rabbits.

Improving translocation success: an experimental study of anti-stress treatment and release method for wild rabbits

Translocation is an important tool in conservation biology. However, translocation success is generally low for numerous animal species, therefore experiments are required for improvement. We carried out an experimental translocation of European wild rabbits (Oryctolagus cuniculus). The results may be of great interest for conservation biology, although we used a common species. As rabbits are known to experience a high mortality during the first days following release, it was necessary to assess the influence of handling trauma and environment novelty, respectively, and ways of suppressing them. Both tranquillization treatment during handling and a ‘soft’ release protocol (acclimatization pens in the new territory) were tested. Tranquillization did not increase survival, while the effect of acclimatization depended on sex. Females survived better when acclimatized, while males showed the opposite tendency. This difference is discussed in terms of sex-specific social behaviour, which is possibly an important correlate of translocation success. Finally, environmental stress seemed to override handling stress in determining the level of early survival for translocated wild rabbits.

Influence of prey densities in the distribution and breeding success of Bonelli's eagle (Hieraaetus fasciatus): management implications

Diet, prey availability, and breeding success were studied in a population of Bonelli's eagle (Hieraaetus fasciatus) in the province of Granada, SE Spain. The densities of the main prey species, European wild rabbit (Oryctolagus cuniculus), red-legged partridge (Alectoris rufa), wood pigeon (Columba palumbus), and rock dove (Columba livia), representing 90.2% of the biomass, were analysed in 19 territories occupied by pairs of Bonelli's eagles and 15 potential territories that were unoccupied but appropriate for nesting. We found no significant differences in prey density between the two types of territories. Contrary to other raptor species, we found no significant relationship between the density of their main prey species and the distance of the neighbouring pairs, either between that density and breeding success. These findings, together with the prior knowledge of nest-site selection of this eagle in the study area, can be used for proper planning of conservation strategies. These should avoid unnecessary effort to increase the eagle's food supply, and should promote the reintroduction of individuals to suitable sites for Bonelli's eagle.

Evaluation of the Association of Parasitism with Mortality of Wild European Rabbits Oryctolagus cuniculus (L.) in Southwestern Australia

Abundances of the parasitic nematodes Trichostrongylus retortaeformis and Passalurus ambiguus, and 8 Eimeria species were estimated by fecal egg and oocyst output in 12 discrete free-ranging populations of wild rabbits (Oryctolagus cuniculus) in southwestern Australia. Comparisons of parasite egg and oocyst counts were made between those rabbits known to have survived at least 2 mo after fecal samples were collected and those rabbits that did not survive. There were significant negative relationships between parasite egg and oocyst counts and survival when all age groups and collection periods were pooled for several species of coccidia and for T. retortaeformis. However, when the same comparisons were made within rabbit age groups and within collection periods, there were very few significant differences even where sample sizes were quite large. The differences indicated by the pooled analysis for coccidia were most likely due to an uneven host age distribution with respect to survival, combined with an uneven distribution of the oocyst counts with rabbit age. The result for T. retortaeformis was similarly affected but by a seasonal pattern. Parasitism by nematodes and coccidia did not appear to be an important mortality factor in these rabbit populations, at least at the range of host densities we examined. This suggests that other factors must have been responsible for the observed pattern of density-dependent regulation in these rabbits.

Factors Influencing the Fecal Egg and Oocyst Counts of Parasites of Wild European Rabbits Oryctolagus cuniculus (L.) in Southern Western Australia

Abundance of intestinal parasites was monitored by fecal egg and oocyst counts for samples of wild rabbits Oryctolagus cuniculus with different levels of imposed female sterility from 12 populations in southwestern Australia. Differences in egg counts of Trichostrongylus retortaeformis between seasons and age groups were dependent on the sex of the host. Pregnancy may have been responsible for these differences because egg counts were consistently higher in intact females than in females surgically sterilized by tubal ligation. Egg counts for Passalurus ambiguus were influenced by season and host age but there were no differences between sexes or between intact and sterilized female rabbits. No differences were detected in the oocyst counts of the 8 species of Eimeria between male and female rabbits or between intact and sterilized females. Seasonal differences were detected in oocyst counts of Eimeria flavescens and Eimeria stiedai. The overwhelming determinant of coccidian oocyst counts was host age, with 6 species being much more abundant in rabbits up to 4 mo of age. There was a suggestion that egg counts of T. retortaeformis and oocyst counts of several species of Eimeria were reduced in populations where rabbit numbers had been depressed for at least 2 yr, but there was no evidence that short-term variations in rabbit numbers had a measurable effect on parasite abundance.

From population structure to individual behaviour: genetic analysis of social structure in the European wild rabbit (Oryctolagus cuniculus)

The European wild rabbit (Oryctolagus cuniculus) lives in stable, territorial breeding groups, with male-biased natal dispersal, female philopatry, and a polygynous mating system. It was introduced into Britain in the 11th century and kept in captive warrens as a food and fur resource. Populations expanded in the wild in the 18th century. Microsatellite markers were employed to examine the genetic structure of wild rabbit populations on three spatial scales: macrogeographic structure of 17 populations in East Anglia, microgeographic structure of a tagged population in the grounds of the University of East Anglia over four consecutive years, and pairwise kinships and individual movement within this tagged population. Populations across East Anglia were found to be genetically distinct, and heterozygote deficits were observed at all loci indicating sub-division within sampled populations. Analysis of the tagged population confirmed that rabbit populations are genetically sub-divided among social groups. Studying this population over four consecutive years revealed that as the population size increased, the number of social groups increased. Analysis of individual pairwise relatedness of females indicated that individuals did not necessarily group with kin, and behavioural data indicate that an optimum group size may exist which maximizes reproductive success.

From population structure to individual behaviour: genetic analysis of social structure in the European wild rabbit (Oryctolagus cuniculus)

Abstract The European wild rabbit ( Oryctolagus cuniculus ) lives in stable, territorial breeding groups, with male-biased natal dispersal, female philopatry, and a polygynous mating system. It was introduced into Britain in the 11th century and kept in captive warrens as a food and fur resource. Populations expanded in the wild in the 18th century. Microsatellite markers were employed to examine the genetic structure of wild rabbit populations on three spatial scales: macrogeographic structure of 17 populations in East Anglia, microgeographic structure of a tagged population in the grounds of the University of East Anglia over four consecutive years, and pairwise kinships and individual movement within this tagged population. Populations across East Anglia were found to be genetically distinct, and heterozygote deficits were observed at all loci indicating sub-division within sampled populations. Analysis of the tagged population confirmed that rabbit populations are genetically sub-divided among social groups. Studying this population over four consecutive years revealed that as the population size increased, the number of social groups increased. Analysis of individual pairwise relatedness of females indicated that individuals did not necessarily group with kin, and behavioural data indicate that an optimum group size may exist which maximizes reproductive success.

Population structure and genetic variation of european wild rabbits (Oryctolagus cuniculus) in east anglia

The European wild rabbit (Oryctolagus cuniculus) is an introduced species in Britain, and populations have been profoundly influenced by both man and disease. In stable environmental conditions, distinct social behaviour is observed, and this social structure leads to significant genetic structuring at the intrapopulation level. In this study, European wild rabbits were sampled from 17 sites across the East Anglian region of Britain and genotyped with nine microsatellite loci. Genotypical proportions deviated significantly from Hardy-Weinberg equilibrium, reflecting a degree of population subdivision and non-random mating. Several estimates of measures of population genetic structure revealed that populations are genetically distinct and have small effective population sizes. These distinctive properties are seen to be the combined effects of the social structure and random drift acting on bottlenecked populations after myxomatosis. It is concluded that the genetic structure seen in rabbit populations today is unlikely to reflect historical structuring present before myxomatosis, but that it results from recent events.