The loss and mismanagement of suitable habitat, fragmentation of smaller woods and the grubbing out of hedgerows are the main factors threatening Muscardinus avellanarius.
Climate adds to the overall problem, as dormice prefer a clear distinction between seasons. Mild winters cause hibernation to be interrupted and the animal loses energy, while cool summers mean that less food is available at critical times.
Predominantly nocturnal, dormice prefer the woodland edge with a wide range of shrubs and trees, especially small sections of old, coppiced hazel cut in a long rotation of around 12 to 15 years. This type of habitat best provides their favoured diet: berries, nectar, insects, nuts. flowers and catkins.
The range of the hazel doormouse covers Europe from Turkey and Russia to the United Kingdom.
Muscardinus avellanarius is considered as a "Lower Risk" sub-category "near threatened" species by the IUCN Red List.