A decade after the Macuxi people won a bloody legal battle to expel rice planters from their reservation in a remote part of Brazil, their hold over ancestral lands has come under threat again from new right-wing President Jair Bolsonaro.

The sprawling 1.7 million hectares (6,600 square miles) of savannah on the border with Venezuela – a reservation called Raposa Serra do Sol – is home to 25,000 native people whose main livelihood is raising cattle.

But the land remains coveted by commercial farmers and mining prospectors, who believe the area is rich in minerals such as gold, diamonds, copper, molybdenum, bauxite and even niobium, a metal used to strengthen steel that Bolsonaro considers “strategic”.

“In the fight for our land rights, 21 of us died,” says Chief Aldenir Lima, the leader of the 70 communities on the reservation. “Since then we recovered what we had lost and today, the white farmers’ rice plantations have been replaced by our cattle herds.”

That could change if Bolsonaro follows through on his promise to review the borders of the reservation – part of his push to repeal a ban on commercial farming and mining on indigenous lands.