Current red squirrel conservation strategies in Ireland that include the planting of non-native conifer trees are likely to have a negative impact on the species survival, according to newly published research led by Queen’s University Belfast and St Andrews University. Rather, native predators in native woodland are vital for the continued survival of the species in Ireland and Britain.
The work to inform the study was carried out by researchers from Queens’ and St. Andrews together with Ulster Wildlife and citizen scientists, and utilised camera traps to study over 700 sites across Northern Ireland over a five year period for red squirrel, grey squirrel and pine marten activity.
The continued recovery of the pine marten has been previously linked with the recovery of the red squirrel, due to it being an effective predator of the grey squirrels which outcompete reds in many habitats and can also spread a lethal disease to reds, which they themselves are immune to. Red squirrels are generally better able to escape pine martens in complex woodland and forest habitat; however, in conifer plantation habitat this does not appear to be the case, and plantations planted with the intention of protecting red squirrels are “likely to have a damaging impact on the species survival” according to the study. This is likely due to the lack of grey squirrels as alternative prey for pine martens in conifer plantation habitats, as well as the fact that the simplified nature of the landscape means that there is a lack of 3D structure for the squirrels to use to their advantage and a lack of suitable crevices in trees to provide them with refuge.
Consequently plantation habitats, thought to have been advantageous for red squirrels due to the lack of greys, which aren’t able to take advantage of the small seeded cones of the conifers, may in fact leave them very vulnerable to predation.
Whilst the restoration of native predators is vital to a healthy ecosystem, and is of particular benefit to red squirrels in terms of suppressing the non-native grey squirrel, it is now clear that this must also be done in conjunction with the restoration and protection of native, structurally diverse, multi-layered woodland.