The most efficient defence against invasive alien species is prevention — basically a border patrol blocking new species.
Is é an modh cosanta is éifeachtaí i gcoinne speicis choimhthíocha ionracha ná iad a chosc — níl i gceist go bunúsach ach teorainn a chruthú chun cosc a chur ar scaipeadh na speiceas nua.