<P> Roughly 5,000 species of animals and 29,000 species of plants are protected by CITES against over-exploitation through international trade . Each protected species or population is included in one of three lists, called appendices (explained below). The Appendix that lists a species or population reflects the extent of the threat to it and the controls that apply to the trade . </P> <P> Species may be split - listed meaning that some populations of a species are on one Appendix, while some are on another . Some people argue that this is risky as specimens from a more protected population could be' laundered' through the borders of a Party whose population is not as strictly protected . The African bush elephant (Loxodonta africana) is currently split - listed, with all populations except those of Botswana, Namibia, South Africa and Zimbabwe listed in Appendix I. Those of Botswana, Namibia, South Africa and Zimbabwe are listed in Appendix II . Listing the species over the whole of its range would prevent such' laundering' but also restricts trade in wildlife products by range states with good management practices . There are also species that have only some populations listed in an Appendix . One example is the pronghorn (Antilocapra americana), a ruminant native to North America . Its Mexican population is listed in Appendix I, but its U.S. and Canadian populations are not listed (though certain U.S. populations in Arizona are nonetheless protected under the Endangered Species Act). </P> <P> Species are proposed for inclusion in or deletion from the Appendices at meetings of the Conference of the Parties (CoP), which are held approximately once every three years, the most recent of which was CoP (CoP 17) in Johannesburg, South Africa from 24 September to 5 October 2016 at the Sandton Convention Center . </P> <P> Species in the Appendices may be proposed for addition, change of Appendix, or de-listing (i.e., deletion) by any Party, whether or not it is a range State and changes may be made despite objections by range States if there is sufficient (2 / 3 majority) support for the listing . These discussions are usually among the most contentious at CoP meetings . </P>

Who enforces the convention on international trade in endangered species