14 DAY TRIAL // Usually the snails live peacefully on the Louisiana grass, but since the 1999-2001 drought the snails have reproduced out of control and the grass has become more sensitive to various parasites carried by the snails.
Furthermore, climatologists predict that due to global warming the area will suffer an increasing number of droughts.
Brian Silliman from Forida University, the author of a study on this subject published in the last issue of Science magazine, has counted in a wetland in Louisiana around 2,000 snails on square meter. "There were snails on every inch of grass", Brian Silliman said.
In the last six years more than 100 000 hectares of US southern cost has disappeared. Although human activity is a major reason for this in some areas, it appears that the snails' activity isn't negligible either.
In order to prove this Silliman and his colegues have created snail-free zones in marshes by caging out the creatures. Grass flourished in these areas but died outside of them. The researchers also mimicked the effects of drought by increasing the salinity of patches of marsh. In these areas, the grass became sickly and the snails thrived.