WP1 - Experimental design
WP1 is dedicated to 1) selection of paired study landscapes along landscape gradients and 2) experimental enhancement of honeybee densities.

1. Selection of paired study landscapes along the landscape gradients
For this purpose, 32 study landscapes (radius 2000m) are selected along two independent gradients: 1. the area percentage of organic farming and 2. the area percentage of semi-natural habitats used as nesting sites and foraging habitats by bees.

Figure 1: Along the independent gradients of the area contents of organic farming and near-natural habitats, landscapes with and without flower strips are selected respectively (schematic representation shows the respective end points of the gradients). The study landscapes have a radius of 2000 m, the inner circle represents a radius of 500m, in which the transect surveys are conducted.

2. Experimental increase of honeybee densities.
In 2022, the effects of increased honeybee densities on wild bee abundance, plant-pollinator interactions, and pathogen transmission along both landscape gradients will be studied experimentally. For this purpose, eight of the original 16 landscape pairs will be selected, which represent very well the gradients of area shares of organic agriculture and semi-natural habitats.