The Philippines has replaced Brazil as the most murderous country in the world for people defending their land and environment, according to research that puts a spotlight on the administration of President Rodrigo Duterte.

More than three defenders were killed across the world every week in 2018, according to the annual toll by the independent watchdog Global Witness, highlighting the continued dangers facing those who stand up to miners, loggers, farmers, poachers and other extractive industries.

The latest global total of 164 deaths was down from 2017’s peak of 201, a decrease that campaigners partly put down to growing focus on the subject by indigenous groups, NGOs, the United Nations and the media.

But Global Witness said companies and governments were increasingly using non-lethal tactics to quash dissent, including criminalisation and threats, while killings remain at an alarmingly high level.

For the first time since the annual toll began in 2012, Brazil did not top the list. The number of defenders murdered in South America’s biggest nation fell in 2018 by almost two-thirds, from 57 to 20. This was partly due to an overall decline in homicide rates across the country, but also came ahead of a transition of power and rising international attention.

Last year the UN environment programme put more pressure on governments to protect defenders and organised a conference in Rio de Janeiro to push for international recognition of the human right to a healthy environment. There was also more media attention on the problem, including from the Guardian, which ran a series about land and environment defenders in conjunction with Global Witness.

Indigenous groups said they had contributed to the decline thanks to a better reporting mechanism for alerting the outside world to murders that might otherwise have gone unreported.

“We should be the ones recognised for this change because we are the ones who are drawing attention to what is happening,” said Sônia Guajajara, an indigenous activist.

It is also possible that land-grabbers now have more power to get what they want without resorting to violence, because the agricultural lobby has an increasingly dominant position in politics.

Campaigners fear last year’s decline in Brazil could be short-lived if a new phase of conflict erupts as a result of President Jair Bolsonaro’s efforts to weaken indigenous territorial rights and protections for nature reserves. Underlining these concerns last week, Emyra Waiãpi, an indigenous leader, was murdered in the Waiãpi indigenous reserve in the state of Amapá ahead of an invasion by dozens of illegal miners.

A Waiãpi man in the Waiãpi reserve in Brazil, where an indigenous leader was murdered last week. Photograph: AFP Contributor/AFP/Getty Images

In the Philippines, 30 defenders were killed last year, following 48 in 2017, which was the highest ever recorded in an Asian country. A third of the deaths were on the island of Mindanao, which is at the centre of the Duterte administration’s plans to allocate 1.6m hectares of land to industrial plantations. Half of the deaths in the Philippines were related to agribusiness.

Globally, mining was the sector responsible for the most killings – 43. But the sharpest rise was in murders of people trying to protect water sources, which increased from four to 17. This included conflicts over hydropower in Guatemala, the country that witnessed the sharpest spike in killings, from three to 16, making it the deadliest country per capita, according to Global Witness.

The London-based group cautioned that its tally of confirmed killings was likely to be an underestimate of the global total because killings still go unreported in many parts of the world. This year it also focused on the increasing use of courts to quash opposition to lucrative projects.

“Overall, there is no sign that the underlying causes of violence are improving. In fact, they look to be worsening. Governments in some of the worst-affected countries, from Brazil to Mexico to India, are prioritising business opportunities for extractives and agricultural companies over the protection of the environment and human rights, setting the stage for more conflict over land.

“This is being matched with a global crackdown on protest and freedom of expression, from recognised authoritarian regimes like China and Russia to longstanding democracies like the US,” said Alice Harrison, a senior campaigner at Global Witness.

“Likewise, the use of courts to criminalise defenders is another weapon of oppression that’s being used in both the global south and north against people who threaten the power and profits of government and big business.”