By increasing tree cover in the tundra region.
Tundra is a biome in which the growth of trees is prohibited by the low heat of the area. The tundra region remains under the cover of ice till summer arrives. The vegetation of the Tundra region incorporates shrubs, grasses, lichens etc. Due to contemporary environmental changes, there is an increment in tree cover in the region. The increased tree cover pulls the red foxes from the south.
As red foxes belong to the category of omnivore animals an improvement in tree covers would expand the quantity of food available. For example, kernels, legumes, grasses, birds including squirrels, mice, and rabbits.
