Factors affecting the abundance of rabbits (Oryctolagus cuniculus) in England and Wales

Forecast increase in invasive rabbit spread into ecosystems of an oceanic island (Tenerife) under climate change

The European rabbit (Oryctolagus cuniculus) is a pest and a conservation problem on many islands, where its heavy grazing pressure threatens many endemic plants with extinction. Previous studies in its native and introduced range have highlighted the high spatial variability of rabbit abundance at local and landscape scales, depending on many factors such as the existence of different habitats. Modeling of the species can be useful to better understand spatial patterns and to prioritize actions, especially in those regions in which rabbits have become invasive. Here, we investigate the distribution of the European rabbit in Tenerife (Canary Islands, Spain), where the species was introduced during the 15th century and has subsequently changed vegetation composition. Added to the direct effects of rabbits on vegetation, climate change could also have implications for rabbit populations, especially in the alpine ecosystem. To evaluate that, we estimated rabbit abundance in 216 plots randomly distributed on Tenerife island (61 in the alpine ecosystem), modeled the potential current spatial abundance of the species and considered how it might vary under different climate change scenarios. We associated rabbit abundance to a wide selection of abiotic, biotic, and human variables expected to influence rabbit abundance on the island. We found a positive correlation between rabbit abundance and temperature and a negative correlation in the case of precipitation. Hence, according to the models' projections, climate change is expected to enhance rabbit populations in the future. Current higher densities were related to land disturbance and open areas, and a remarkable increase is expected to occur in the alpine ecosystem. Overall, we consider that this study provides valuable information for land managers in the Canary archipelago as it reveals how global warming could indirectly exacerbate the conservation problems of the endemic flora in oceanic islands.

Seasonality and risk factors for myxomatosis in pet rabbits in Great Britain

Myxomatosis is a highly contagious, frequently fatal viral disease affecting both wild and domesticated European rabbits across many areas of the world. Here we used electronic health records (EHRs) collected from pet rabbits attending a sentinel voluntary network of 191 veterinary practices across Great Britain (GB) between March 2014 and June 2019 to identify new features of this disease's epidemiology. From a total of 89,408 rabbit consultations, text mining verified by domain experts identified 207 (0.23 %) cases where myxomatosis was the only differential diagnosis recorded by the attending practitioner. Cases occurred in all months but February and were distributed across the country. Consistent with studies in wild rabbits, the majority of cases occurred between August and November. However, there was also evidence for considerable variation between years. A nested case control study identified important risk factors for myxomatosis within this pet animal population including season, sex, age, vaccination status and distance to likely wild rabbit habitats. Female entire rabbits were twice as likely to be a case (odds ratio (OR) 1.98, 95 % confidence interval (CI) 1.26-3.13, p = 0.003), suggesting a novel role for behaviour in driving transmission from wild to domesticated rabbits. Vaccination had the largest protective effect with vaccinated rabbits being 8.3 times less likely to be a case than unvaccinated rabbits (OR = 0.12, 95 % CI 0.06-0.21, p = <0.001).

Habitat factors related to wild rabbit population trends after the initial impact of rabbit haemorrhagic disease

The European wild rabbit (Oryctolagus cuniculus) is an introduced pest species in Australia and New Zealand. Rabbits have a devastating negative impact on agricultural production and biodiversity in these countries, and Rabbit Haemorrhagic Disease (RHD) is currently included in control strategies for rabbit populations. On the other hand, the European wild rabbit is a key native prey species in the Iberian Peninsula. Since the arrival of RHD, however, rabbit populations have undergone dramatic decreases and several predator species at risk of extinction are currently dependent on the rabbit population density. Therefore, from the point of view of biodiversity conservation, evaluating habitat correlates and trends of rabbit populations after the first RHD epizootic is of great interest to improve the long-term control or promotion of wild rabbit populations. We estimated the relationship between habitat factors and long-term population trends as well as the relationships between habitat factors and rabbit abundance 2 and 14 years after the arrival of RHD in several Iberian rabbit populations. We observed that only 26% of surveyed populations seemed to experience an increase in rabbit abundance over the last 12 years and that this increase was higher in the low-rabbit-abundance areas of l992, leading to high rabbit abundance in 2004. Our results suggested that short- and long-term impacts of RHD were related to habitat quality. The initial impact of RHD was higher in more suitable habitats, but increasing long-term population trends were positively related to good habitat quality.

The emergence of rabbit haemorrhagic disease virus: will a non-pathogenic strain protect the UK?

Rabbit haemorrhagic disease virus emerged in China in 1984, and has killed hundreds of millions of wild rabbits in Australia and Europe. In the UK there appears to be an endemic non-pathogenic strain, with high levels of seroprevalence being recorded, in the absence of associated mortality. Using a seasonal, age-structured model we examine the hypothesis that differences in rabbit population demography differentially affect the basic reproductive rates (R(0)) of the pathogenic and non-pathogenic strains, leading to each dominating in some populations and not others. The strain with the higher R(0) excluded the other, with the dynamics depending upon the ratio of the two R(0) values. When the non-pathogenic strain dominated, the pathogenic strain caused only transient mortality, although this could be significant when the two R(0) values were similar. When the pathogenic strain dominated, repeated epidemics led to host eradication. Seroprevalence data suggest that the non-pathogenic strain may be protecting some, but not all UK populations, with half being 'at risk' from invasion by the pathogenic strain and a fifth prone to significant transient mortality. We identify key questions for empirical research to test this prediction.