Land reserves occupied by indigenous groups in Brazil are at risk of being lost because of a constitutional decision that could affect hundreds of cases, warns Professor Anthony Pereira.

The case, which is sparking protests in Brasília, is over a federal regional court ruling that it would only recognise tribal lands occupied by native communities at the time Brazil's constitution was ratified in 1988.

The Brazilian Supreme Court is now being asked to determine whether this was an excessively narrow interpretation of the constitution of October 1988, thereby infringing on indigenous rights.

Professor Pereira, of King’s Brazil Institute, said that there is much at stake around the upcoming ruling by the Supreme Court, although there is some evidence that it might not uphold the decision.

Speaking to France24, he said:

The case has arisen in part because farmers, backed by President Bolsonaro, are lobbying for legal certainty of agricultural access, in a move that could reduce the amount of land in existing indigenous reserves and make it more difficult to demarcate new reserves.

The President believes that indigenous groups have too much land reserved for the amount of people using them.

Campaigners have warned that a loss in court could set a strong precedent for further degradation of native rights, and could see indigenous groups facing a huge struggle for their culture.

Environmental protection of the land could also be at risk, as deforestation generally happens at a much lower rate within indigenous reserves than it does outside them."

Huge protests by native groups have occurred in Brasilia, with thousands of people attending to urge the Supreme Court to rule against the cut-off date.