How pine marten recovery in Britain is benefiting red squirrels by suppressing grey squirrel populations through predation.
Pine marten recovery represents a remarkable example of natural predator-prey dynamics providing conservation benefits. The mechanism - grey squirrels are more ground-dependent than red squirrels, making them more vulnerable to marten predation - is producing measurable conservation outcomes. Individual grey squirrels killed by pine martens experience predation death, which is a welfare harm but one within natural ecological processes rather than from human management. The conservation benefit for red squirrels - reduced competitive exclusion and disease pressure - represents a population welfare improvement. Pine marten recovery is also beneficial for their own welfare, with expanding populations having access to more natural territory.