Figure 1. Map of the field site and study design at Jordbärsmuren.

The mother colony was situated in the centre: pots were placed at 1, 5, 10, 30, 50, 80, 150, 300 and 600 m in each direction at in total 36 sampling stations. Note: The area with the sampling stations from 50 m and inwards are represented by a large white circle. Background aerial photographs: © Lantmäteriet Gävle 2011 (Permit I 2011/0094).