To study the impact of these depressions on the reproductive success of the frogs, scientists based at the University of Vienna installed a series of plastic bowls to collect rainwater at regular intervals in a patch of rainforest in French Guiana and monitored frog populations in their test and control plots.

It was found that the frog populations expanded rapidly in both the areas with the bowls and nearby plots, from 148 frogs the season before the bowls were installed to 246 frogs two years later, while no increase was seen in plots far away from the man-made peccary wallows.