Culling wildlife hosts to control disease: mountain hares, red grouse and louping ill virus.
Culling wildlife hosts is often implemented as a management technique to control pathogen transmission from wildlife to domestic or other economically important animals. However, culling may have unexpected consequences, can be expensive and may have wider implications for biodiversity and ecosystem functioning. We assess the evidence that culling mountain hares Lepus timidus is an effective and practical way to control louping ill virus in red grouse Lagopus lagopus scoticus. Evidence from the available literature is limited, restricting our ability to reliably assess the effectiveness of culling mountain hares to control ticks, louping ill virus, or increase red grouse densities. Furthermore, the information required to assess the cost-benefit of this management strategy is lacking. The population response of mountain hares to culling is not well understood and the possible effects on their conservation status and the upland ecosystem remain unexplored. We conclude that there is no compelling evidence base to suggest culling mountain hares might increase red grouse densities. Synthesis and applications. Widespread culling of wildlife is not necessarily effective in reducing disease or improving economic returns. The use of wildlife culls for disease control should be proposed only when: (i) the pathogen transmission cycle is fully understood with all host-vector interactions considered; (ii) the response of wildlife populations to culling is known; and (iii) cost-benefit analysis shows that increased revenue from reduced disease prevalence exceeds the cost of culling.