From the Congo Basin to Kenya, India and Paraguay, the designation of forest land as "protected areas" has brought homelessness, hunger and persecution to indigenous peoples who have lived there for centuries, rights experts say, pointing the finger at governments and the conservation groups they work with.
In many cases, international conventions and national laws oblige states to respect legal and customary ownership of land by indigenous tribes, consult them on how that land is used, and involve them in efforts to conserve the natural resources it contains.
But on Sunday, Victoria Tauli-Corpuz, the U.N. Special Rapporteur on the Rights of Indigenous Peoples, will tell the World Conservation Congress in Hawaii that there remains a huge gap between the rules on paper and reality on the ground.
"It is not easy to find good stories about how these are implemented in practice," she told the Thomson Reuters Foundation. "There are still a lot of indigenous people who have been evicted - and are still being evicted - from their territories because of the creation of national parks, and (for) those who have been evicted, there is no recourse."
In addition, even though land is supposedly being set aside for the purpose of protecting its natural value, this is often followed by state-backed exploitation of the oil, minerals, trees and other resources on it, Tauli-Corpuz and indigenous leaders warned.
Edwin Vasquez, leader of the Huitoto Indians in Peru and head of COICA, a coordinating body for indigenous organizations in the Amazon River Basin, said national parks were being carved out of indigenous territories in his country, preventing native people from hunting and fishing there.
"(The government) wants to create a national park with no indigenous people, and then they declare the exploitation of the resources on it as a national priority, and they exploit those resources for the development of the country," he said. "They see us as an obstacle to development."
Peru's new government said last month that economic growth this year would be boosted partly by an increase in mining production of around 20 percent.
And yet mining projects in the South American nation are frequently beset by social conflicts, particularly over contamination of water.
Vasquez said his people had proved they are good custodians of the land and are not opposed to economic development.
But they want the government to consult with them on the process, as it has agreed to do under International Labour Organization Convention 169 and national law.
Since 2012, Peru's government has, in fact, been working on measures to improve consultation with the backing of Germany.
The Office of the Ombudsman has developed guidelines for the different groups involved, and has trained more than 500 representatives of indigenous peoples and 6,500 government officials on the right to prior consultation.
When the project ended in 2015, around 40 consultations had been completed or were ongoing, limiting conflict in the oil sector, German's development agency noted.
However, such efforts by donor governments are rare, according to Gonzalo Oviedo, senior adviser on social policy at the International Union for Conservation of Nature (IUCN), which is organizing the Sept. 1-10 Hawaii congress.
When donors provide bilateral funding to set up and maintain protected areas, they should attach conditions to the aid, 80 to 90 percent of which goes directly to governments, he said.
"What we want is that every donor that provides funding for conservation should oblige the recipients of the funding to implement standards about the respect of indigenous people's rights and... community rights," he said. "They don't do it today."
Oviedo said progress has been made in aligning the interests of conservation organizations and indigenous groups since the early 1990s, particularly in Latin America.
The main spark for conflict today comes from the economic agendas of developing states that want to extract natural resources to fuel their prosperity, he added.
"It is not as simple as going to a poor country and telling the government to stop doing anything of commercial value in these areas because you have to protect those communities," he said.
In Brazil, for example, indigenous peoples are a tiny minority, yet hold around a sixth of the country's land, Oviedo said, leading to the argument that resources on their land should be exploited to ease poverty among the wider population.
Carrot and stick
U.N. rapporteur Tauli-Corpuz said conservation groups, which include the powerful WWF and The Nature Conservancy, should pressure the governments they work with to safeguard the rights of indigenous peoples in protected areas.
"If that's not happening, those conservation organizations are also equally culpable of neglecting the indigenous peoples and not protecting their basic human rights," she said.
Oviedo said conservation organizations, including IUCN, could be "a bit more brave" in addressing issues like land ownership when they work with governments.
IUCN is taking steps to protect indigenous rights, he added, such as declining to recommend sites for World Heritage status if governments do not put good policies into practice, and creating a "green list" of protected areas where they are.
But there is a limit to how much conservation organizations can achieve on their own, he said.
"The kind of political changes that are needed don't necessarily happen just because of conservationists asking for that," he said. (Reporting by Megan Rowling @meganrowling; editing by Ros Russell. Please credit the Thomson Reuters Foundation, the charitable arm of Thomson Reuters, that covers humanitarian news, women's rights, trafficking, property rights and climate change. Visit http://news.trust.org)