The Convention on International Trade in Endangered Species (CITES) is a treaty to protect wild animals and plants against over-exploitation through commercial trade.
The signatories of the treaty, which came into force in 1975, are 182 countries and the European Union, with 5,600 animal and 30,000 plant species on their radar.
The Johannesburg conference starting Saturday will sift through 62 proposals to tighten or loosen trade restrictions on some 500 species.
Species can be listed on three CITES appendices to ensure that trade is legal, sustainable and traceable.
Appendix I outright bans international trade in species facing extinction
Appendix II allows trade, under stringent conditions, of species that may become threatened if no steps are taken
Appendix III is a list of species named unilaterally by countries that want other nations' cooperation to prevent illegal or unsustainable exploitation
Among the high-profile cases expected to draw attention in Johannesburg are:
Trade in elephant ivory is strictly forbidden, but Namibia and Zimbabwe want the ban lifted so they can sell stockpiles and fund community elephant conservation initiatives. The radical move contradicts proposals put forward by a coalition of 29 other African countries that want a complete end to ivory trade.
Swaziland submitted a last-minute proposal that would allow it to sell its stockpile of around 330 kilograms (730 pounds) of rhino horns and thereafter 20 kilograms annually from legally and non-lethally harvested horns.
But activists fear this may exacerbate the current rhino poaching crisis and CITES has recommended that the controversial proposal be rejected.
The elusive scaly ant-eating animal is critically endangered and ranked as the most trafficked mammal on earth with more than a million poached in the past decade.
Several proposals have been submitted by 19 countries to have trade in all nine pangolin species in Africa and Asia be totally banned.
Nine west African countries want a ban in the commercial trading of lions. Numbers of African lions have declined more than 40 percent in two decades due to habitat loss and prey shortages.
But populations have increased 12 percent in Botswana, Namibia, South Africa and Zimbabwe due to good wildlife management.
Sharks are often viewed as fierce predators but are in decline due to overfishing spawned by a growing appetite for their fins to make fin soup, an Asian delicacy.
The fins are sliced off while sharks are still alive and the fish are tossed back into the water. There are proposals to add silky and thresher sharks to the 10 species of sharks and rays under appendix II.
Commercial demand for rosewood, a highly valuable timber, has escalated in Asia, fuelling a massive, cross-border criminal network.
There are five proposals that could affect the trees that are threatened with legal and illegal logging around the world.