Could refuges from human disturbance stem the decline of Capercaillie in
Scotland?
Abstract
Capercaillie in Scotland have declined in number and contracted in range
since the 1970s, most remaining in Strathspey on the northwest flank of
the Cairngorm mountains. Strathspey, however, is popular for recreation
and suffers anthropogenic disturbance from visitors and their use of new
forest tracks and remote, off-track areas. Disturbance reduces the area
of forest available to Capercaillie. Refuge areas wherein the creation
of new tracks is not allowed, and in which recreation is not encouraged,
are a management option that might mitigate such effects. We simulate
this possibility for the area covered by Forest and Land Scotland’s
Strathspey Land Management Plan. Spatially explicit, stage-based matrix
models assessed the potential of protecting this population with refuges
under ‘optimistic’, ‘central’ and ‘pessimistic’ scenarios based on
observed demographic data. Fifteen potential refuges comprised
less-disturbed areas of forest still used by Capercaillie. We simulated
population growth using combinations of 1, 3, 5, 7, 10, 12 and the full
complement of 15 refuge areas. An increasing Capercaillie population
could be sustained by a network of refuges, but refuges could not arrest
a wider population decline due to causes other than disturbance. This
suggests that refuges could play a role in mitigating the increasingly
damaging effects of disturbance on Capercaillie in the Strathspey LMP
but that the birds’ long-term prospects will depend upon improving their
performance more widely.