Is Morales putting his eco-credentials on the road to ruin?

The Isiboro Sécure Indigenous Reserve and National Park might strike many as paradise on earth. Located in the verdant headwaters of the Amazon basin, the protected area is home to a stunning array of species, from howler monkeys and spectacled bears to myriad birds and insects, not to mention 64 native communities and billions of tons of forest carbon.

It is the last place where the credentials of Evo Morales as a globally renowned defender of indigenous rights and the Pachamama, or Earth Mother, seem likely to be called into question. But Bolivia's President now finds himself engulfed in a bitter dispute over his plans to put a £260m road through the middle of this stunning wilderness.

On Monday, about 300 members of the Chimane, Mojeño and Yuracaré indigenous communities that inhabit the 3.4 million-acre park – universally known by its Spanish acronym Tipnis – began a march against the proposed highway, from the steamy provincial town of Trinidad up some 10,000ft to the Andean capital La Paz. The group is expected to take about 30 days to complete the 400-mile trek, during which time organisers expect sympathisers to massively swell their numbers.

"President, tell me at what point we betrayed our nation," said Adolfo Chávez, leader of the Indigenous Peoples' Confederation of Bolivia. "We want to live in peace, with development that respects our lands. Your shovels will crash into our children. That is why you do not want a binding consultation. So our spears and arrows will be ready for the mechanical diggers which want to destroy our virgin territory."

For his part, Mr Morales, who last year took Bolivia on a lonely stand against the Cancun climate accord which he said would endorse "ecocide and genocide", appears equally determined to push ahead with the road, saying it will be built "no matter what". He believes it will integrate remote rural communities into Bolivia's economic development. Earlier this week, the President accused the protesters of intransigence. "The dialogue [process] is always open. I am very sorry that they do not want to participate in the dialogue," he said. "I can understand that this is a political act."

Although Mr Morales has nationalised oil and gas reserves and imposed contracts with higher royalties on foreign mining firms, Bolivia remains one of the poorest nations in the Western hemisphere. The President has been unable to break the country's dependence on the export of raw commodities, which have taken a high environmental and human toll.