LOIBOR SIRET - Laly Lichtenfeld has reason to be cautious. White outsiders have left some painful memories in this region of vast plains in the north of Tanzania. Thousands of people were expropriated to create the nearby national parks of Tarangire and Manyara, as well as the Serengeti, further north on the Kenyan border. In East Africa, there are few tribes who have paid as heavy a tribute to conservation as the Maasai. A third of Tanzania is a designated protected area, three times more than the world average.

Laly is a white American who has devoted most of her life to lions, the subject of her Yale doctoral thesis in social ecology. She founded the wildlife conservation organization African People and Wildlife, and lives at the top of a hill overlooking the savannah. It sounds romantic, like the stories of many of the Westerners who have figured in African history since colonial times. But the reality in Loibor Siret is tougher.

Simson comes back from the local village, very upset. A farmer has just killed an elephant that trampled his field. The authorities have arrested him and removed the elephant's tusks, which will join the stock of ivory kept by the wildlife bureau of the local government district. Such incidents occur almost daily. Lions, zebras... 24-year-old Simson has the difficult task of managing conflicts that can in an instant set peaceful communities ablaze. “It's not easy,” he says. “You have to try to understand the villagers instead of just punishing them.” Simson works under the authority of the village chief, but receives his salary from African People and Wildlife, the association founded by Laly and her husband Charles, who is also American.

The couple arrived here a dozen years ago after finishing their studies. The village agreed to give them a bit of land, and they have made a quiet home here, trying not to repeat the errors of previous NGOs whose misadventures have been the subject of local gossip.

In his 2008 Oxford doctoral thesis, Hassanali Thomas Sachedina recounted some of the stories of misguided experiments, humiliated locals and anger. “If someone came from the African Wildlife Foundation (an American organization) with suitcases full of cash, no one here would touch the money and we'd chase them away,” said the president of the village council in Emboret, a village not too far away across the immense plain of Simanjiro, which has grown too small for the ever-expanding population of semi-nomadic herders.

Giraffes, zebras, elephants and lions

After the Serengeti-Maasai Mara region in Tanzania and Kenya, Taragire is the second-largest area for the migration of large wild African mammals. But the 1,771-square-mile (2,850-square-kilometer) national park covers less than 15% of the ecosystem, where an age-old migration is repeated every year. When the annual rains fall, during the six months from December to June, the animals leave the waterlogged park for more hospitable terrain.

This is the period when tensions rise along the corridors traversed by thousands of giraffes, zebras, elephants, wildebeest... and lions, following their prey, and sometimes attacking cattle and goatherds. Tanzania is home to about 40% of the world's remaining population of lions, of which there are between 20,000 and 40,000 worldwide.

Fields of corn and earthen huts with dung-plastered walls are spreading inexorably over the Tarangire. In certain areas they sit right at the edge of the national park, their owners longing for access to the good pasture within, forbidden to their herds. The high grass inside the park contrasts with the big white flowers that cover the plain outside. The beauty of the flowers is misleading -- they are a sign of an exhausted, infertile soil.

In 2009, the four corridors around the park were judged by the Wildlife Conservation Society (WCS) to be in a critical condition. WCS was charged by the Tanzanian public research institute for wildlife, (TAWIRI) to analyze the health of the 30 or so wildlife corridors between the country’s protected areas. The researchers say their findings show that it is probable that these corridors will be totally occupied within five years. Ecologists believe that it is essential to preserve the flow between the great reservoirs of wildlife, which are necessary for the intermingling that is crucial to the survival and health of wildlife. For the government, preserving the corridors is also an economic consideration. No animals would mean no more tourism, which provides almost 15% of the nation's annual revenue.

A living wall against lions

“We have nothing but problems with these animals. During the rainy season, lions and hyenas attack us constantly,” says Naipotoki Bahati. She is surrounded by a crowd of children. Her husband has taken his herd out to the savannah to graze. In the middle of the circle of family huts, she points to the enclosure in which their animals are penned at night. Lions are not frightened of humans, and easily cross the barrier made of plants. To save the big cats, Laly Lichtenfeld has had the idea of surrounding these pens instead with an impassable wall.

“If you want to do something for conservation here, you don't talk to people about protecting the animals but first you ask them how you can help them solve their problems, and find a solution that makes sense in the local context," she says. Here, the most important thing is to protect the people and their animals. The “living walls,” as they have been called, are made from a local myrrh shrub planted in a dense hedge surrounded by wire mesh. The first one was installed in 2009. There are now more than a hundred, each costing $500, one-quarter of which is paid by the herders -- the price of two or three goats. The number of lion attacks has plummeted. But the ecologist admits that it is not enough. Only the local population can protect these corridors, and to do this, conservation needs to be profitable for them.

Not far away, in the Babati district, Nashon Macokecha runs the Burunge Wildlife Management Area (WMA). The government started these community structures 10 years ago. Burunge is one of the first to have experimented with the idea of having the local population manage the wildlife.

Nashon Macokecha, who works for the Ministry of Natural Resources, has taken up the challenge energetically, although he sometimes shows signs of discouragement. “There are only three of us to watch over 4,350 square miles (7,000 square kilometers), with a motor scooter, old rifles, and no way to communicate.”

Participative conservation

In the past few days, he has found 20 elephant carcasses. He cannot compete with armed poachers. The WMA includes 10 villages and about 30,000 people. To benefit from the special status, the villagers had to agree to put aside part of their land as a protected zone for wildlife.

These zones have been turned into tourist concessions or hunting preserves, whose private operators pay a fee. In 2011, this produced revenue of $319,375. Only one-third goes to the villagers; the rest goes to the central or local government, in order to -- officially at least -- finance conservation.

However, in a region so poor that the World Food Program hands out lunches in the schools, this amount is not nothing. Classrooms and a well have already been built. “I have always loved conservation,” says Rama Damani, smiling broadly. The statement sounds rehearsed, but Rama, 42, is an important person. He represents the local people and has the title of president of the WMA. For him, there is no question: “It is better than before.” Burunge is considered a promising experiment in participative conservation.

A giraffe crosses the asphalt road. Zebras walk by a herd guarded by young Maasai shepherds draped in red. Whose lands are these? Do they belong to people, or to the wildlife? The preservation of the wildlife corridors is becoming an impossible challenge. The government of Tanzania has made it a priority, but does not have the human or financial resources for the job.

A few months ago, the government called for help from the great international conservation organizations, asking them to pay more attention to the problems of local populations.