Hazel dormice (Muscardinus avellanarius) in a regenerating clearing: the effects of clear-felling and regrowth thinning on long-term abundance dynamics

The hazel dormouse (Muscardinus avellanarius) is a rare and threatened species in many European countries. However, it is common and widespread in Lithuania where forest management practice, particularly small-scale clear-felling, is considered to be favourable for this species. The long-term study was carried out in regenerating clearing which fell in the area of the dormouse study site. The forest plot was clear-felled in the winter 2001/2002, and regrowth was thinned in 2004, 2007, 2010 and 2014. During 2003–2019, average adult dormouse density in regenerating clearing (1.6 ± 0.7 adults/ha) was significantly higher than average density in the entire area of the study site (1.0 ± 0.3 adults/ha). Clear-felling had only short-term negative effect on dormouse abundance. It increased already in the 3rd year after clear-felling when dormouse density exceeded 2 adults/ha and reached its maximum in the 7th–9th years after clear-felling. Dormouse abundance decreased since the 14th year after clear-felling. Thinning of regrowing woody vegetation had only temporary negative impact on dormouse abundance in the current or next year depending on the timing of thinning in early summer or autumn, respectively. Practice of small-scale clear-felling could be used for the hazel dormouse conservation in countries where this species is endangered.