Fig. 1. Overview of the dispersal experiment.

A The four dispersal bag treatments contained one of two substrates, either glass slides or grass litter. The Closed treatment, a negative control, was placed on the ground and closed to all dispersal using a 0.22 µm nylon mesh bag. The Elevated treatment was placed on tables 60 cm above the surrounding vegetation in bags open to dispersal from above (2 mm window screen) but not below (0.22 µm nylon). The Overhead treatment was placed on the ground and open to dispersal from above (2 mm window screen) but not below (0.22 µm nylon). The Open treatment was placed on the ground and open to all dispersal (2 mm window screen). B Dispersal routes were isolated by comparing the treatments in a nested manner: contribution by the above surface route was inferred by the difference between the Elevated and Closed treatments; the near-surface route by the difference between the Overhead and Elevated treatments; and the below surface route by the difference between the Open and Overhead treatments.