What durable food sources replace fresh growth in the water vole's winter diet?

Roots, rhizomes, and the bark from woody stems and shrubs

When the readily available supply of soft, tender leaves and green stems disappears as seasons change, the water vole is compelled to shift its foraging strategy dramatically to survive the leaner winter period. This shift involves turning toward tougher, less palatable, yet more durable components of the surrounding vegetation. Specifically, their winter diet must include excavated roots and rhizomes, which supply essential stored carbohydrates and calories that the plants have sequestered underground for dormancy. Additionally, they consume the bark found on nearby woody stems and shrubs, although this is generally considered a survival measure rather than a preferred dietary staple due to its higher lignin and cellulose content.