A device for protecting an area against terrestrial gastropods includes at least one barrier that includes a base for securing the barrier to the periphery of the area to be protected, a ceiling wall connected to the base, a grid extending along and spaced apart from the ceiling wall, a space between the ceiling wall and the grid, and at least one blocking means for preventing the gastropods, of the size category targeted by the barrier, from crawling in the said space. Barriers targeting small gastropods can be integrated into barriers targeting large gastropods.