Ranger Kalibumba stood no chance. Five bullets tore into his chest and abdomen as he attempted to intercept a fleeing gunman who’d just stolen a motorcycle and killed its owner. A wildlife ranger based in Virunga National Park in the Democratic Republic of the Congo, Kalibumba died shortly after being shot. He was 36 years old and left behind eight children.

Kalibumba is the latest in a long line of rangers to perish while defending the Congo’s abundant wildlife and rich ecosystems, and the latest victim of a disturbing global pattern of killings, violent attacks, and persecution of those working on the front line of environmental protection.

According to the International Ranger Federation, more than a hundred national park wardens, rangers, and wildlife and forest guards have died or been seriously injured in recent years across Africa, Latin America, Asia, Europe, and the United States. The dossier reads with disturbing monotony: “killed in firefight with rebels”; “shot by loggers”; “murdered”; “assassinated”; “shot in armed robbery”; “[shot] with his own sidearm.”

In response, nongovernmental organizations, aid organizations, law-enforcement agencies, and governments are scrambling to train, equip, fund, and better organize rangers and wardens. Increasingly, that’s meant providing arms and military-style training, particularly to those in conflict-ravaged regions.

Recent years have seen a number of private “eco-militias” established in several African countries, often with the tacit support of governments that find themselves unable to effectively police their natural resources.

Bruce Hayse, a U.S. doctor and environmental campaigner, sparked headlines in 2001 after the president of the Central African Republic granted him permission to raise a mercenary force to combat poachers decimating the country’s wildlife and terrorizing villagers.

Hayse, a founding member of the radical Earth First! network, set up Africa Rainforest and River Conservation to train and equip a 400-strong, fully-armed militia force, which, as well as patrolling the country’s borders and wilderness areas, was tasked with fixing roads, building health clinics and schools, and advising locals how to use natural resources in a sustainable manner.

The militia, comprised in part of hired guns from South Africa, was given permission to shoot on sight and engage with illegal hunters and wildlife smugglers. Despite some initial successes, including military operations targeting a number of elephant-poaching gangs, the practicalities of effectively maintaining a private army quickly proved problematic.