Fast breeders

Climate change could lead British rabbits to become more susceptible to rabbit haemorrhagic disease

source: Deborah MacKenzie
New Scientist July 28 2001 p15

Rabbit haemorraghic disease (RHD) can affect both captive and wild rabbits, and was linked to the deaths of 64 million farmed rabbits in Italy in 1986. It is thought to have spread from Central Europe, and had reached China by 1984, with 140 million domestic rabbits dying in an outbreak there. Spain has also been affected, and wild rabbits have been imported into Spain due to a shortage for hunters.

RHD has yet to make much impact in Britain, though it was first noted there in 1994. Stirling University’s Peter White argues that this may be due to a natural vaccine in the British rabbit population, in the form of a variant of the RHD virus that does not have much effect on rabbits. Populations with a high average age tend to have more rabbits with immunity from this natural vaccine. Slower rates of reproduction tend to mean a higher average age for rabbits.

Rabbits tend to reproduce faster when it is warm, and this may explain why rabbits are worse affected in southern Europe than in Britain. They are also worse affected in southern England than in Scotland. There will be a smaller percentage of immune, older rabbits in warmer areas, allowing the disease to spread more easily. Global warming could, thus, lead to a decline in rabbit numbers in Britain. White’s research is reported in ‘Philosophical Transactions of the Royal Society B’, volume 356, p1087.