The hazel dormouse (Muscardinus avellanarius) is protected under both UK and European law. However, populations have sharply declined in the UK despite legal protection and conservation efforts: it is estimated that we have lost over a third of the total population since 2000. Although there are likely to be multiple factors influencing this trend, appropriate management of habitats at existing sites is key to retaining populations. Good habitat management plans could also make more habitats suitable and enable dormice to recolonise areas once lost to them.
A juvenile dormouse
The course was in early October, as this is the peak time to see adults and juveniles from a year’s litters. The Isle of Wight is a national stronghold for the species and the People’s Trust for Endangered Species owns Briddlesford Woods, the largest remaining block of ancient semi-natural woodland on the island. As part of the course, we also visited several other sites dormice use, including a conifer plantation and a very young woodland.
The course provides a unique opportunity to handle dozens of dormice and see every life stage. In one day, we checked 160 nest boxes and found 83 dormice, including newborn ‘pinks’. We quickly had to get to grips with nest boxes containing up to eight lively adults and juveniles and to learn to gather their biometric information efficiently.
It is also the only course in the country to cover species-appropriate habitat management in-depth. Traditional landscape and woodland management techniques such as coppicing, hedge-laying and woodcutting have inadvertently helped to maintain optimal habitats for dormice. Unmanaged old woods tend to have dense canopies where heavy shade reduces the understorey. A dense understorey is crucial for dormice, which prefer to move around above the ground. They will make use of bramble banks, hedges, branches and any other dense vegetation. Species commonly found in woodland understorey such as field maple(Acer campestre), blackthorn (Prunus spinosa) and hawthorn(Crataegus monogyna) also tend to be rich in flowers and fruit that are good food sources.
Although dormice are associated with old woodland sites and are certainly found in ancient woodlands, younger woods with open canopies, sunny glades and a rich understorey are optimal for the species. To prove the point, the wood in which we found 83 dormice was not even 15 years old!
I left the course with excellent dormouse handling skills and armed with information on how to design and adapt habitat management plans for the species. We need to take every opportunity, particularly on landscape-scale projects in southern England, to sensitively manage and enhance habitat for dormice.