Disease reservoirs in complex systems: a comment on recent work by Laurenson et al.

Abstract

L.), anda vector of the louping-ill virus. They go on to showthat a reduction in hare density was coincident with areduction in tick numbers, a reduction in louping-illseroprevalence in grouse and an increase in grousebreeding success. They concluded that, in the presenceof mountain hares, ‘it may not be possible to take largeharvests of red grouse’, and make moorland manage-ment for grouse uneconomic. Their case for mountainhares being important in the persistence of louping-illis weakened by the lack of a rigorous experimentaldesign but, moreover, they have failed to demonstratethat the removal of mountain hares has any effect onthe potential harvest of red grouse, making their con-clusions unreliable. We argue that the impact of loupingill on grouse dynamics, and the role that hares play inthis, needs further investigation before any firm con-clusions can be drawn or recommendations made forgrouse-moor management with respect to the cullingof mountain hares.