Some of the legal principles and tools contained in these agreements and guidelines include the precautionary approach, prevention of harm, prior-informed consent, and risk assessment. They must do all they can to find out the consequences of their action. Permits, certificates and other administrative procedures and measures are required by a number of agreements, especially with regards to quarantine. The IPPC requires phytosanitary certificates between the national plant protection offices of importing and exporting countries. The Antarctic treaty requires permits to be issued before the importation of certain animals and plants, especially those not native to the Antarctic Treaty Areas.
Precaution dictates a comprehensive approach to risks across sources and media.
From a legal perspective, once a prima facie case is made that a risk of harm exits, the burden is on the polluter or introducer of an alien species to minimise or eliminate the risk. Whenever certain risks are established, prevention is mandatory, even when no cause-effect relationship between an activity and its environmental effects have been established. The agreements that require the application of risk assessment for national regulations include, for example, the GATT Agreement on Sanitary and Phytosanitary Measures. While by no means complete, this chart provides examples of activities in the international and regional arena on alien invasive species. It also provides an opportunity for discussion on the synergies between and among these and other international agreements and institutions on the development of effective tools and mechanisms on the introduction, control and eradication of alien invasive species.