Nouabalé-Ndoki National Park, in northern Republic of Congo, consists of sixteen hundred square miles of Central African rain forest and is jointly administered by the Congolese ministry of forests and the Wildlife Conservation Society, of the Bronx. Lying just east of the Sangha River, the park is home to significant populations of western lowland gorillas, chimpanzees, giant forest hogs, and, above all, to some five thousand forest elephants. Like elephants everywhere in Africa, those in the park are, increasingly, under siege. Two years ago, when I visited, the park’s technical adviser, Tomo Nishihara, told me that the numbers of elephants in the park and its surrounding buffer zones had fallen from ten thousand to five thousand in just five years. “That gives us five more years before they’re gone,” he said.

Elephant ivory fetches eleven hundred dollars a kilo on Asian markets, and, in recent years, Nouabalé-Ndoki has been battling increasingly professionalized poachers. On July 25th, a group of newly trained rangers were patrolling the Ndoki River in a buffer zone around the park periphery when they came upon a poachers’ camp. The poachers opened fire with AK-47s, but the rangers, who had been trained in small-unit tactics, were able to spread out, fire back, and eventually take the camp. They recovered six pairs of elephant tusks, an AK-47, and six empty magazine clips, and promptly used their satellite phones to alert a rapid-reaction unit to set up roadblocks along nearby logging roads. There they captured not the fleeing poachers (who got away) but a man named Samuel Pembele, who park officials say is a main player in one of the most notorious ivory-trafficking groups in northern Congo, a group locally known as 2Pac (named for one of its founders). Pembele, who denounced others in the group, including another ringleader, will go on trial, on November 15th, in the Sangha River town of Ouésso, on charges of killing an endangered species. He could get five years.

Mark Gately, the director of the Wildlife Conservation Society’s Congo program, in Brazzaville, described these events to me by phone and e-mail and told me that, in response to pressure from poachers, Nouabalé-Ndoki had been forced to “professionalize and better arm the park’s rangers.” He credited the success to the use of “real-time communications” involving a control room at park headquarters, satellite phones in the field, and, especially, to a new Wildlife Crime Unit, in Ouésso, under the direction of Jean Robert Onononga, a Congolese wildlife biologist. Onononga and his staff do undercover work against poaching rings and also track cases through the courts to make sure they come to justice.

The arrest of a key member of the 2Pac group is a bright spot in an otherwise complicated season for African elephants. In late August, Paul Allen, the investor and philanthropist, announced the results of a “Great Elephant Census,” funded by his Vulcan foundation. The census, a two-year aerial and ground survey designed to calculate the numbers of Africa’s elephants, found them in drastic decline, having dropped by almost a third between 2007 and 2014, largely due to poaching. The survey found that only some three hundred and fifty thousand elephants remain, with more than a third of those in one country, Botswana, which, until recently, has been largely undisturbed by poaching.

Allen’s survey was released in time for a meeting of the Convention on International Trade in Endangered Species, or CITES, a treaty signed by a hundred and eighty-two countries, which sets international rules governing the trade of endangered animals and plants. This year, the meeting, which ended on October 5th, was held in Johannesburg, and John Scanlon, the organization’s head, described it as “one of the largest and most critical meetings in the forty-three-year history of the convention.”

At the top of the agenda was a proposal—put forward by the African Elephant Coalition, a group of twenty-nine African nations whose members cover eighty per cent of the present elephant range—to ban the sale of ivory from the few remaining areas of Africa where elephants are not yet seriously endangered. CITES regulates the trade in species by grouping them in appendices, corresponding to the degree to which an animal is considered threatened. Most African elephants are Appendix 1, which means they are considered critically endangered and have a status that bans the international trade of their ivory altogether. But four southern African nations —South Africa, Namibia, Zimbabwe, and Botswana—still contain threatened, but relatively healthy elephant populations, and they are listed in Appendix 2, which means that the trade of their ivory has to be strictly regulated. As part of this designation, CITES allowed the southern African countries to make two supervised “one-off” ivory sales, in 1999 and 2008. The two sales were deeply controversial, and critics—including the African Elephant Coalition nations—have argued that the one-off legal ivory introduced into international markets provided cover for the subsequent infusions of poached, illegal ivory.

The proposal put forward by the African Elephant Coalition would have “uplisted” the status of southern Africa elephants to Appendix 1. South Africa, Zimbabwe, and Namibia strongly objected to the proposal—though Botswana, which has lately experienced a significant increase in poaching, supported it. Tshekedi Khama, Botswana’s minister of environment, wildlife, and tourism, spoke of his nation’s concern that poaching was moving south. “No population should be considered secure,” he said. ”Put simply, a threat to elephants anywhere is a threat to elephants everywhere.”

The uplisting vote needed a two-thirds majority and, had it been held just among African nations, it would have passed easily. But the European Union, with twenty-eight votes, came out unanimously against the measure and thus was able to prevent the uplisting. The logic behind the European Union’s vote was that Appendix 1 categorization was meant to protect populations that were in steep decline and that this did not describe the elephants of Zimbabwe, Botswana, South Africa, and Namibia.

To many people on the front lines of elephant conservation, the defeat of the effort to uplist the Appendix 2 elephants was infuriating. Lee White, the head of Gabon’s National Park Agency, told the Independent that “The E.U.’s decision is a death sentence. Any legal trade will continue to drive illegal international commerce in ivory, which will result in the slaughter of both elephants and the rangers trying to protect them.”

As an alternative, the United States, which also opposed the uplisting, and ten African nations pushed a voice vote on a resolution for all CITES members to close their domestic ivory markets. The Obama Administration has already effectively banned ivory sales in the United States, and China, far and away the biggest Asian market for illegal ivory, announced last year that it, too, will impose a similar ban. (So far, it has provided neither a timetable nor details.) The resolution passed unanimously. The ban is, however, nonbinding.

The Great Elephant Census counted only savanna elephants, which can be spotted from the air. It did not count the smaller, less-well-understood forest elephants that live under the dense canopy of the Congolese Basin. These are the elephants of Nouabalé-Ndoki. As logging roads have carved through their formerly impenetrable habitat, forest elephants, too, have suffered rampant poaching. A 2013 survey found that their numbers had declined sixty-two per cent between 2002 and 2011, and that as few as eighty thousand may remain. Andrea Turkalo, the world’s preëminent forest-elephant biologist, recently co-authored a paper which demonstrated that forest elephants, moreover, are among the slowest-reproducing animals on the planet. Even if poaching were to end, it would take the existing population eighty-one years to return to the population levels of the year 2000.