Can the remaining red squirrel (Sciurus vulgaris) population in England be sustained in the face of epidemic squirrelpox disease?

The native red squirrel faces the extirpation of its remaining meta population in mainland England. This severe population decline at a national scale is due to several factors, however, mortality caused by an epidemic of... [ view full abstract ]

The native red squirrel faces the extirpation of its remaining meta population in mainland England. This severe population decline at a national scale is due to several factors, however, mortality caused by an epidemic of squirrel-pox virus disease, carried by the introduced grey squirrel (S carolinensis), is recognised as the primary cause. Hypothesis: As the grey squirrel population advances northward, carrying squirrel-pox virus, where both squirrel species and the virus come in contact, the disease kills red squirrels. The priority is therefore to prevent red squirrel infection by stopping red and grey squirrels coming into contact. The disease in red squirrels has now extirpated the species in most of mainland England. Surveillance for the disease has informed the many conservation efforts to attempt to conserve the red squirrel. Results: Surveillance has demonstrated that disease in red squirrel-only-populations was relatively self-limiting; that disease only occurs where red squirrels co-exist with grey squirrels; and that sero-prevalence of virus infection in grey squirrels was high. Strategic control of grey squirrels has been effective in disease control. The plight of the red squirrel has sparked public concern in Northern England and led to effective actions, to slow down or prevent the loss of the species. Innovation: This presentation will describe how prime red squirrel habitat areas are protected and defended against grey squirrel incursion; how grey squirrel populations are controlled, and what is done when disease strikes isolated populations. It will describe two specific locations where these actions have been successful. Significance: Although relatively early in the attempt to control squirrelpox disease in England, this work demonstrates that epidemic disease in wild species can be controlled to at least allow the survival of selected small populations. Health really matters in sustaining red squirrels in England.