Study site
Field sampling was carried out in the Central and Southern Black Forest in southwest Germany. The 135 research plots each measured 100 x 100 m in size with a minimum distance of 750 m between plots. These plots belong to the ‘Conservation of forest biodiversity in multiple-use landscapes of Central Europe’ research project (Storch et al. 2020, Fig. 2), and are all located in temperate mountainous forests between 434 m and 1334 m above sea level. The annual average temperature is about 6.9 °C with a yearly average precipitation of 1205 mm (climate station of the city of Titisee-Neustadt, www.climate-data.org , accessed 2020/2/16).
Forests are dominated by Abies alba, Fagus sylvativa andPicea abies growing on cambisol, umbrisol and podzoles. The forest stands are managed with continuous cover forestry (Gustaffson et al. 2019). The bedrock consists of gneiss and granite in the west, with lower Triassic sandstone and middle and upper Triassic limestones towards the east.
We selected the plots to cover a large landscape and forest structure gradient. For the landscape gradient, we set three categories of forest cover within a 25 km radius from the centre of each plot: < 50%, 50–75% and > 75% forest coverage estimated by raster data (state agency of spatial information and rural development of Baden-Württemberg, accessed 2016). Additionally, we obtained the forest structure gradient based on the number of standing dead trees assessed from aerial images ((state agency of spatial information and rural development of Baden-Württemberg, accessed 2016): 0, 1-9, >10. Detailed information can be found in Storch et al. (2020).