Effect of habitat quality and quantity on the occurrence and persistence of the lesser spotted woodpecker (Dryobates minor) across two time periods

Habitat area, forest characteristics, management practices and protected areas have the potential to profoundly impact biodiversity. This is particularly true for specialist species linked to structural complexity and old forest, like the lesser spotted woodpecker ( Dryobates minor ). This study examines how habitat quality and quantity influence the occurrence of this Near-Threatened species across two periods (1985–1988 and 2019–2021) in Sweden. The study was carried out as a citizen science study in a total of 241 sites, each of 200 ha (1.41 × 1.41 km). During the first period 177 sites were surveyed for lesser spotted woodpeckers and in the second period, 118 of these were revisited and 64 new sites selected. In all sites, woodpecker presence or absence was established, and forest characteristics were also described in most sites. In addition we used national land cover data and a database of protected areas. Occurrence of the species was strongly linked to deciduous forest area, both temperate broadleaved (nemoral) and other deciduous types. In particular, each hectare of unlogged forest (without signs of forestry from the last 20 years) is associated with a more than twofold stronger increase in the probability of woodpecker occurrence compared to logged forest. Sites where the species sustained over time, i.e. occurred in both study periods, were characterized by higher habitat quantity and larger proportions of formally protected forest. Additionally, national population trends show that periods of population decline coincide with high logging volumes of deciduous wood on a national scale.