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Simple Summary: The emergence of two strains of rabbit haemorrhagic disease (i.e., GI.1 and GI.2) in the1990s and 2010s, respectively, has been the primary determinant for the decline of wild European rabbits within their native range. We compared the impact of both strains on the wild rabbit populations in Spain using national hunting bags. Our findings showed that GI.1 had a greater impact on wild rabbit populations than GI.2. This disparity is likely to be explained by several factors, such as climatic conditions, host resistance improvement, virulence attenuation, and population density, among others. The outbreaks of two strains of rabbit haemorrhagic disease (RHD) (GI.1 and GI.2) in the Iberian Peninsula have caused substantial economic losses in commercial rabbitries and have affected the conservation of rabbit-sensitive predators due to the dramatic decline of their natural populations. However, the assessment of the impact of both RHD strains on wild rabbit populations has been limited to a few small-scale studies. Little is known about the overall impact within its native range. In this study, we described and compared the effects of GI.1 and GI.2 countrywide by using time series of hunting bag data widely available across the country and compared their trend during the first eight years after the first outbreak of GI.1 (i.e., 1998) and GI.2 (i.e., 2011), respectively. We used Gaussian generalised additive models (GAM) with the number of hunted rabbits as the response variable and year as the predictor to evaluate the non-linear temporal dynamics of the population at the national and regional community levels. The first GI.1 caused a population decline of around 53%, affecting most Spanish regional communities where the disease occurred. The positive trend observed after GI.1 in Spain ended with the initial outbreak of GI.2, which did not appear to cause a national population decline. In contrast, we found significant variability in the rabbit population trend among regional communities, where some increased, and others decreased. Such a disparity is unlikely to be explained by a single factor; rather, it appears to result from several factors, such as climatic conditions, host resistance improvement, virulence attenuation, or population density. Our study suggests that a national comprehensive hunting bag series could aid in elucidating the differences in the impact of emerging diseases on a large scale. Future research should focus on national longitudinal serological studies to shed light on the immunological status of rabbit populations in different regions to better understand the evolution of RHD strains and the resistance gained by the wild populations. [ABSTRACT FROM AUTHOR]

• Roads are often used by agricultural pest species as dispersal corridors. • Rabbit damage to agricultural production has increased in Iberian Peninsula. • We assessed the distribution of rabbit warrens in motorway verges. • Rabbit warren presence correlated positively with the presence of olive groves. • Our modelling approach allows identifying high risk motorway stretches. Pest species cause significant ecological, social and economic impacts, and programs to control them usually target specific landscape features when pests use these to disperse. Roads or railways are often used by pest species as dispersal corridors, but little is known about the specific characteristics of these human infrastructures that facilitate pest species dispersal. This is particularly evident in the case of native agricultural vertebrate pests like the European wild rabbit (Oryctolagus cuniculu s) in the Iberian Peninsula (IP). Rabbit damage to agricultural production in IP has increased notably in recent years. This study uses a 'favourability function' to model the extent to which macroecological favourable conditions for rabbits and different fine-scale variables, including environmental, anthropogenic and agricultural factors, favour the presence of rabbit warrens on the verges of a motorway network in southern IP. For this purpose, we collected rabbit warren locations during car transects using CyberTraker 3.0 installed in a pad along 787 km of motorways. Our results revealed that rabbit warren distribution was widespread along the verges. Rabbit warren presence correlated positively with the presence of olive groves and with macroecological favourable conditions for rabbits. Our results provide strong evidence that rabbits use motorway verges, which are likely to act as dispersal corridors across landscapes. Additionally, our innovative approach, based on a rabbit warren index, the favourability function and a combination of local and macroecological predictors, could be used in many other areas where rabbits cause crop damage to make fine-scale predictions of high risk stretches and, therefore, where to apply mitigation measures. [ABSTRACT FROM AUTHOR]

BACKGROUND Numerous small and medium-sized mammal pests cause widespread and economically significant damage to crops all over the globe. However, most research on pest species has focused on accounts of the level of damage. There are fewer studies concentrating on the description of crop damage caused by pests at large geographical scales, or on analysis of the ecological and anthropogenic factors correlated with these observed patterns. We investigated the relationship between agricultural damage by the European rabbit ( Oryctolagus cuniculus) and environmental and anthropogenic variables throughout Spain. RESULTS Rabbit damage was mainly concentrated within the central-southern regions of Spain. We found that rabbit damage increased significantly between the early 2000s and 2013. Greater losses were typical of those areas where farming dominated and natural vegetation was scarce, where main railways and highways were present, and where environmental conditions were generally favourable for rabbit populations to proliferate. CONCLUSION From our analysis, we suggest that roads and railway lines act as potential corridors along which rabbits can spread. The recent increase in Spain of such infrastructure may explain the rise in rabbit damage reported in this study. Our approach is valuable as a method for assessing drivers of wildlife pest damage at large spatial scales, and can be used to propose methods to reduce human − wildlife conflict. © 2017 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Vaccination campaigns against myxomatosis and rabbit haemorrhagic disease (RHD) are commonly used in translocation programs conducted for the purpose of recovering wild European rabbit populations in Iberian Mediterranean ecosystems. In most cases rabbits are vaccinated ‘blind’ (i.e. without assessing their prior immunological status) for economic and logistic reasons. However, there is conflicting evidence on the effectiveness of such an approach. We tested whether blind vaccination against myxomatosis and rabbit haemorrhagic disease improved rabbit survival in a rabbit translocation program where wild rabbits were kept in semi-natural conditions in three enclosures. We conducted nine capture sessions over two years (2008–2010) and used the information collected to compare the survival of vaccinated (n = 511) versus unvaccinated (n = 161) adult wild rabbits using capture-mark-recapture analysis. Average monthly survival was no different for vaccinated versus unvaccinated individuals, both in the period between release and first capture (short-term) and after the first capture onward (long-term). Rabbit survival was lower in the short term than in the long term regardless of whether rabbits were vaccinated or not. Lower survival in the short-term could be due to the stress induced by the translocation process itself (e.g. handling stress). However, we did not find any overall effect of vaccination on survival which could be explained by two non-exclusive reasons. First, interference of the vaccine with the natural antibodies in the donor population. Due to donor populations have high density of rabbits with, likely, high prevalence of antibodies as a result of previous natural exposure to these diseases. Second, the lack of severe outbreaks during the study period. Based on our findings we argue that blind vaccination of adult rabbits in translocation programs may be often mostly ineffective and unnecessarily costly. In particular, since outbreaks are hard to predict and vaccination of rabbits with natural antibodies is ineffective, it is crucial to assess the immunological status of the donor population before translocating adult rabbits. [ABSTRACT FROM AUTHOR]

We describe the extremely rapid worldwide spread of the Lagovirus europaeus/GI.2/RHDV2/b (henceforth GI.2), the causative infectious agent of the so‐called 'novel' rabbit haemorrhagic disease of the European rabbit (Oryctolagus cuniculus). We tracked down all novel confirmed detections of GI.2 between May 2010 and November 2018 by carrying out a two‐step in‐depth review. We suggest that such spread would not have been possible without anthropogenic involvement. Our results also point out the importance of reviewing and adapting the protocols of virus detection and management in order to control, mitigate and contain properly, not only GI.2, but also new viruses that may emerge in the future. [ABSTRACT FROM AUTHOR]

Context. European rabbits (Oryctolagus cuniculus) are serious economic and environmental pests in Australia and New Zealand. Since the illegal introduction of rabbit haemorrhagic disease virus (RHDV) in New Zealand in 1997, the disease has persisted in most rabbit populations, with major epizootics occurring usually each autumn. Aims. We evaluated the efficacy of the virus as a biological control agent in the southern South Island. Methods. We used an index of rabbit abundance (kills per hunter) based on a region-wide annual rabbit-hunting competition to evaluate rabbit population trends 7 years before and 16 years after the first outbreak of RHD. We also evaluated the influence of rainfall and temperature in the preceding year on post-RHD trends in the index. Key results. Kill rates declined by 60% following the initial epizootic. They remained low for the following 3 years and then increased steadily to intermediate levels punctuated by occasional declines. The instantaneous rate of increase in kill rates during the increase phase was low, but above zero (0.04 per year). No relationship between kill rates and rainfall was apparent, but there was a negative relationship between kill rates and winter temperature in the preceding season. Conclusions. The kill-rate data obtained from this hunting competition suggest that RHD still appears to be killing rabbits. Every 2-3 years over the past decade, kill rates have been as low as they were when government rabbit-control programs were in place before RHD arrived, but the efficacy of RHD as a biological control agent is waning compared with the first outbreaks of the disease. This concurs with findings based on spotlight counts. Implications. The data collected from this hunting competition are a good example of how 'citizen science' can be used to capture large volumes of pest-monitoring data from a wide geographic region for very little cost. The information is a valuable addition to understanding the effects of a major wildlife disease. [ABSTRACT FROM AUTHOR]

Background: Fast‐spreading diseases affecting wildlife populations threaten biodiversity. Two caliciviruses, Lagovirus europaeus/GI.1 and Lagovirus europaeus/GI.2, caused rabbit haemorrhagic disease virus (RHDV) in wild rabbits. Despite having different characteristics, these variants spread quickly, posing a threat to wild rabbit populations. Methods: In this study, we conducted a thorough review of the scientific literature and reports of international organisations of first detections of both variants of RHDV in the Euro‐Mediterranean region. We concentrated on this area to avoid bias due to intentional human introductions. Results: The estimated mean spread rate of GI.2 was higher than that of GI.1 (GI.2: 479 km/year, range: 47–7346; GI.1: 330 km/year, 37–6248). These differences were not statistically significant. This lack of difference may be due to the interactions between each variant's virulence characteristics. Humans may have a dominant effect on their spread. Potential limitations associated with the observational process could have hindered our ability to identify statistical differences. Conclusions: The lack of difference in the spread patterns of the two variants could be due to a biological cause, human facilitation or a lack of statistical power. Adapting protocols to detect diseases in wildlife using homogeneous criteria will be indispensable in the coming years. [ABSTRACT FROM AUTHOR]

Abstract: Techniques for estimating the age of wild animals are crucial to many aspects of the study of population biology. Accurate estimates of the proportion of different age classes in wild rabbit populations would be very useful, and the possibility that it could be obtained from the pellet size holds great appeal. However, this suggestion has created controversy in the literature as this technique has not been validated. This study involved assessment of whether threshold fecal pellet diameters could be used to differentiate adult and juvenile rabbits. The proportion of adults in four wild rabbit populations living in semi-natural conditions was compared with the proportion of animal pellets greater than threshold diameters of 6 mm and 4 mm. Our results suggest that inferring a relationship between the proportion of pellets >6 mm diameter and the proportion of adults in a population is not applicable to European wild rabbits, and that the use of this method could produce erroneous interpretations. The use of a 4 mm pellet diameter threshold appeared to produce even more inaccurate results. Studies that use this technique should include validation, as the results can vary greatly among individuals and populations. [Copyright &y& Elsevier]

Abstract: Recently, a new method for differentiating juvenile and adult rabbits based on faecal pellet size was published. According to this method, pellets >6 mm diameter are inferred to be deposited by adults, while those <6 mm are inferred to be from juveniles or kittens. In this study, we designed a simple experiment to test the accuracy of this methodology. Twelve adult rabbits were housed in individual outdoor cages and their pellets were removed every day for 10 consecutive days. Pellets were separated using a sieve according to their size and counted. Results showed that adult rabbits produce pellets >6 mm diameter in the same proportion as those <6 mm. We also observed a strong influence of the individual rabbit on pellet size; some rabbits produce a high proportion of pellets >6 mm, whereas others deposit mostly pellets <6 mm in size. Our findings demonstrate that pellet size is unsuitable for aging wild rabbits. Field biologists should therefore be cautious when employing the pellet size method of age determination in other wild animals in the absence of validating studies. [Copyright &y& Elsevier]