The effects of restoring a conifer Plantation on an Ancient Woodland Site (PAWS) in the UK on the habitat and local population of the Hazel Dormouse (Muscardinus avellanarius)

Abstract

The common dormouse is a European protected species that is considered at risk during forest management operations in the UK. Historically, they were believed to exist principally in scrub and broadleaved woodlands, especially hazel coppice, but recent evidence has shown that they are present in some conifer sites at low density. Operations to restore conifer plantations on ancient woodland sites (PAWS) with native broadleaves may be especially hazardous to dormice populations, since dormouse densities are generally lower here so sudden perturbations may cause local extinction. Recent policy for restoring PAWS to broadleaved and the need to comply with European legislation has emphasised the need to devise appropriate but pragmatic forest management protocols involving the phased removal of conifers over time. Dormice were handled and individually marked on a single 12 ha conifer PAWS site from 2000 and a density index calculated from 2002 to 2007. In four adjacent study areas, a different form of PAWS restoration was carried out in 2003 to remove c. 33% of conifers. The effects on dormouse numbers, damage to artificial hibernation nests, and regeneration of suitable habitat were recorded. Monitoring indicated that dormouse populations were sustained in each study area after management, suggesting that at this site, conifer removal operations did not have a significant detrimental effect on the dormouse population. Damage to artificial hibernation nests was significantly different between the four study areas. The least damage occurred in the study area containing large group fells due to potential refuge areas, and worst in the traditional standard overall thinning. Measured differences in shrub vegetation throughout each study area showed that numerous small group fells or a few larger group fells subsequently regenerated to form a better vegetation structure for dormice than the traditional standard overall thinning. The implications for forest managers of the results from this single site are discussed.