In a victory for conservation groups, Botswana, Namibia, South Africa, and Zimbabwe yesterday withdrew controversial proposals to expand international trade in ivory. In a compromise deal reached at a meeting of the U.N. Convention on International Trade in Endangered Species, delegates agreed that ivory sales will be delayed for at least two years, until a monitoring system can be put in place to prevent poaching. The southern African nations want to sell stockpiles of ivory and use part of the proceeds to fund elephant conservation programs. But Kenya and India argue that any ivory sales lead to increases in elephant poaching.