Many of the most persistent ant pests are not native to this country. Two of these, Argentine ants and red imported fire ants, are well known to drive out less aggressive native ants, often resulting in severe consequences to the ecosystem.
This has been well documented with red imported fire ants, and more recently with Argentine ants. A study showed that the coast horned lizard in California is threatened because the Argentine ant has taken over areas where native harvester ants use to live. Harvester ants are the primary food for the lizard. The lizard wont eat Argentine ants, apparently because they taste bad.
Another study in South Africa showed that native ants bury large seeds of many kinds of native plants. When a fire comes through, these buried seeds germinate and new plants emerge. But when Argentine ants take over, they don’t bury plant seeds. Any fire coming through burns most plant seeds that are above ground. There is a ten-fold drop in the number of large-seeded plants that germinate after a fire in areas infested by Argentine ants.