The updated status of the threatened garden dormouse Eliomys quercinus

The garden dormouse (Eliomys quercinus), a native European rodent species, has disappeared from large parts of central and eastern Europe and is considered extinct in some countries. We reviewed national red lists and the available information on the occurrence and distribution of the species in all countries where it was previously reported. The garden dormouse is considered regionally extinct in Estonia, Finland, Latvia, Lithuania, Slovakia, Belarus, Poland, and Ukraine, and is classified as endangered or critically endangered in the Czech Republic, Flanders (Belgium), Germany, and the Netherlands. Even in Western Europe, an area considered a stronghold for the species, the garden dormouse is Near Threatened in Portugal and Italy, and there are reports of local declines or extinctions in Spain, France, and Switzerland. The current understanding cannot account for the significant reduction in the garden dormouse’s range in central and eastern Europe. This decline is probably due to the interplay of various factors, such as the considerable decline of insect biomass (a main food resource for the species), exposure to rodenticides used in pest control operations, and the bioaccumulation of pesticides and other pollutants. Therefore, it is crucial to develop an Action Plan for the species at the European level and swiftly implement conservation interventions.