A group of men dressed in military green run along the shore of Lake Kariba as the first rays of sunlight peek through the thick clouds rolling overhead. Their war cries are the only sound piercing the dawn silence.

The men - all members of the Bumi Hills Anti-Poaching Unit - are drilling in preparation for another day of guarding against wildlife poachers in Zimbabwe's Sebungwe region, about 400 kilometers (250 miles) northwest of the capital Harare.

Nicholas Milne, founder and trust manager of the non-profit Bumi Hills Foundation

"Drills instill discipline, respect and teamwork," Nicholas Milne, 34, says later as the rangers prepare for deployment. "They also keep the rangers in peak physical condition," adds Milne, who is founder and trust manager of the non-profit Bumi Hills Foundation. The foundation has been running the anti-poaching unit since 2009.

These are all vital skills for saving the area's elephants - which are being targeted for their ivory. Aerial surveys carried out between 2007 and 2014 across sub-Saharan Africa as part of the Great Elephant Census revealed that the Sebungwe region has suffered some of the highest elephant declines on the continent: Numbers dropped by 74 percent.

Milne, a jovial fast-talker, suddenly becomes serious when the conversation turns to how dear the elephants are to him. "If allowed to continue unabated, this wholesale slaughter could result in the entire population being wiped out within the next 10 years," he says.

That's where the anti-poaching unit comes in.

In the early morning sunshine, the unit sets off on foot to find traces of poachers

Tradition and technology

In the early morning sunshine, the unit sets off on foot to find traces of poachers. The rangers are recruited locally and from across Zimbabwe. For security reasons, the foundation won't reveal more exact information.

It's a dangerous job. The poachers have guns - so the unit is armed, too. Still, rangers - like former police officer Lewis (not his real name) - say they want to preserve the country's wildlife for generations to come.

"If we have resources and willpower, the war against poachers will be won," Lewis says. "It is a war, life is at risk - but who will do it for us if we just sit back and fold our hands?" he asks.

Detecting illegal hunters is not easy. Rangers have to cover a lot of ground. And poachers usually work at last light so they can escape under the cover of darkness if the sound of shots raises the alarm.

"If not detected, the gang will stay in the area and shoot more animals until they physically cannot carry any more ivory, before making their way out of the area to the designated rendezvous with the middleman or trader," says Milne.

A combination of traditional bush skills and new technology that provides real-time patrol data and instant access to previously-collected information has cut the rate of elephant poaching to zero in the past two years.

Previously, three elephants were shot per day in the 150-square-kilometer (58-square-mile) patrol area.

A combination of traditional bush skills and new technology has cut the rate of elephant poaching to zero in the past two years

Real action

During the conversation, Milne suddenly reaches for his two-way radio. "There is a man to the west of….," he begins, launching into a detailed, technical exchange. He's spotted a suspected poacher along the lakeshores, about 500 meters (1600 feet) away. The rangers radio back and forth as Milne directs his team to their target.

Within minutes, he is smiling. The unit has intercepted the suspect - turns out he was just a local subsistence fisherman, who had wandered in the wrong direction. There are designated fishing areas along the lake for the local Batonga people, away from main wildlife areas.

The rangers record and save the fisherman's details with specialized software. Following a warning, they wave him on.

Buyers pay from $1,000 to $2,100 per kilogram for ivory

Organized crime

People caught in the act of poaching or in possession of ivory face a nine-year mandatory prison sentence. But the prospect of jail time doesn't put them off. The ivory trade is big business, with a complex, globalized, organized crime web behind it.

Poachers "are 'recruited' by middlemen, normally from areas further afield, who provide them with weapons, ammunition and money in return for ivory or other wildlife products," says Milne.

Buyers pay from $1,000 to $2,100 (940 - 1900 euro) per kilogram (2.2 pounds) for ivory.

The unit's intelligence indicates that poachers receive from $150 to $200 ( 140 to 187 euro) per kilogram (2.2 pounds) a small fortune for people living in extreme poverty.

That's why, Milne says, his foundation is working with locals to find alternative sources of income, and to raise awareness with community development programs.

Going it alone

"If we do not do it, who will?"

The wildlife minister of Zimbabwe, Oppah Muchinguri, says she is aware of the poaching problem in the Sebungwe area. She attributes it to a porous border with Zambia on the other side of Lake Kariba, where ivory can more easily make it out of the country to traders and consumers in countries like China.

"We can't change that," Muchinguri told DW. "But we are introducing drones to ensure that there are more patrols along the river," she says, referring to the Zambezi River that flows to Lake Kariba.

"We are even having to introduce [new] boats and technology to make sure we are up-to-date with the poachers."

But so far, no government boats or drones are policing Lake Kariba, leaving wildlife at the mercy of poachers, and the rangers of the Bumi Hills unit to defend the elephants alone.

"There are times when we wonder if it is all worth it," Milne says as he scans the shoreline and lake in the distance.

"But if we do not do it, who will? We are eternal optimists, as most Zimbabweans are, believing that one day our efforts will make a difference - so we just have to keep at it."