When he was offered a leading role in the documentary The Ivory Game (2016) by its producer, Leonardo DiCaprio, the conservationist Wayne Lotter modestly gave the credit instead to his wildlife rangers, who led the way in tracking down one of Africa’s most notorious poachers, thought to be responsible for 10,000 elephants’ deaths. Lotter preferred to be in the background, while the spotlight fell on the cause for which he fought: saving the dwindling populations of Africa’s wild elephants, through practical, dogged, on-the-ground tracking of poachers and protection of their prey.

Lotter has been shot dead in Dar es Salaam, aged 51. Although the identity of his killers is not known, the murder may have been connected to one of the criminal groups involved in wildlife killing and ivory trafficking in Tanzania. These groups have turned what used to be small-scale ivory poaching into a highly organised international criminal enterprise that exists mainly to service Chinese demand for ivory and other rare animal products. “The more you go after them, the more situations where there is confrontation between poachers and rangers will take place,” Lotter said last year. “There are going to be risks.”

Lotter knew early on that he wanted to work in wildlife. He was born in Johannesburg, son of Vera and Charles Lotter, and took a master’s degree in nature conservation at Tshwane University in 1990 before beginning his career as a ranger in South Africa. He rose to become invasive alien species programme coordinator for the government wildlife organisation Ezemvelo KwaZulu-Natal Wildlife.

As he gained experience in the field, it became clear to him that the dangers to the wildlife on his ranges were changing rapidly. Africa’s elephants are in crisis, owing to the threats of habitat loss, human encroachment and farming, climate change and above all the militarisation of poaching. At least 20,000 elephants were killed for their ivory in 2015, and last year the UN announced that elephants were being killed faster than they were being born.

Facebook Twitter Pinterest Last year the UN announced that elephants were being killed faster than they could be born. Photograph: Alamy

In 2006, responding to the new dangers, Lotter helped to co-found the Pams (Practical Area Management System) Foundation in Tanzania, having previously served as vice-president of the International Ranger Federation. Pams has 200 game scouts and other law enforcement personnel on the ground in Tanzania. He also helped establish the National and Transnational Serious Crimes Investigations Unit in Tanzania, which has been instrumental in bringing high-profile poachers and criminal syndicates to book.

A charismatic man, described as having “an eccentric sense of humour”, Lotter espoused a particular sort of muscular conservationism. He recognised that high-minded promises made by governments and civic leaders on the need to preserve wildlife were meaningless unless matched by boots on the ground. Only the local community could provide the level of support and of practical protection needed, he believed, and when given the tools and educated in the necessary skills, they could provide an effective approach.

This robust policing was also, he knew, a highly dangerous tactic. Like many of the “defenders”, he realised that the forces he was up against were murderous. He received numerous death threats over the years. Among those arrested as the result of his investigations were Boniface Malyango, nicknamed Shetani Hana Huruma, meaning “the devil has no mercy”, who is thought to have killed or ordered the killing of 10,000 elephants; and Yang Fenglan, accused of ivory smuggling.

He is survived by his wife, Inge, two daughters, Cara Jayne and Tamsin, and his parents.

• Wayne Lotter, conservationist, born 5 December 1965; died 16 August 2017