The Marsh Arabs, or Madan, saw their centuries-old way of life virtually destroyed under Saddam Hussein's regime.
BBC News Online
Many fled their remote homeland in the marshes of southern Iraq when the central government reasserted its authority across the country after uprisings following the 1991 Gulf War.
Campaigners say the Marsh Arabs are victims of genocide
In addition, massive government drainage schemes have turned the region from one of the world's most significant wetlands to a wasteland of cracked, salinated earth.
Baroness Emma Nicholson, Chairman of the Amar Foundation, which provides aid to Marsh Arab refugees, believes they are the victims of genocide.
In targeting the Madan, Saddam Hussein "has destroyed the livelihoods and many of the lives of nearly half a million people", she told BBC News Online.
The United Nations Environmental Programme says about 90% of the up to 20,000 square kilometres of marshlands have been lost because of drainage and upstream damming in "one of the world's greatest environmental disasters".
Estimates suggest there were around 400,000 Madan in the 1950s, but that this had dropped to 250,000 by 1991.
There may now be as few as 20,000 living in the marshes.
The wetland region where the Tigris and Euphrates rivers split into meandering ribbons and lakes before flowing into the Persian Gulf has been home to human communities for five millennia.
The Marsh Arabs built complex, arched buildings from reeds
The Bible places the Garden of Eden near the two rivers (Genesis chapter 2, verse 14).
Until 1991, the Madan lived traditionally, growing rice and dates, raising water buffalo, fishing and building boats and houses from reeds.
After coalition forces drove Iraqi troops from Kuwait in the Gulf War, rebellions spread across the south and north of the country.
Shia Muslims in the city of Basra on the southern edge of the marshes played a key role. Some Marsh Arabs took part.
Ecosystem has "completely collapsed"
Impact on wildlife and biodiversity is "catastrophic"
The marshlands are home to:
Two-thirds of west Asia's wintering wildfowl
11 globally-threatened bird species
3 globally-threatened mammal species
Iraqi Government forces put down the uprisings brutally, bombing civilians from military helicopters. Between 30,000 and 60,000 people were killed, according to the United States.
Tens of thousands of army deserters, political opponents and others sought shelter in the remote marshes, Human Rights Watch says.
Repression was stepped up in the southern Shia towns and the Iraqi regime began large-scale hydro-engineering projects in the marshes, building dams, canals and embankments. Water levels began to drop.
In 1992 and 1993 reports emerged of a military campaign to flush out the wetlands.
Refugees fleeing to Iran described artillery and aerial attacks on civilian areas, arrests and executions, mine-laying and the destruction of homes and properties.
If the marshlands are not restored... then the marsh people will fade into history, and our generation will be responsible for the deliberate extinction of one of the oldest races in the world
They said the Iraqis used napalm and chemical weapons and poisoned the marsh waters, although the accusations have not been confirmed.
In August 1992, US, UK and French forces imposed a no-fly zone to stop attacks on southern Iraq from the air, but offensives continued on the ground.
"The army's favourite tactic is to blow up villages selectively and then sow mines in the water before retreating," wrote the Observer journalist Shyam Bhatia, who visited the marshes in 1993.
Iraq said its engineering programmes were for reclaiming agricultural land and that it was running a relocation programme for the benefit of the marsh dwellers.
As much as 90% of the marshlands have been destroyed
But the UN special rapporteur on Iraq, Max van der Stoel, concluded in 1995 that he had found "extremely little evidence" of successful land reclamation and "indisputable evidence of widespread destruction and human suffering".
A decade later, about 40,000 Marsh Arabs are known to be living in camps or squatter settlements in Iran.
The rest are thought to be internally displaced in Iraq, but no one knows how many are still alive.
About 40,000 Marsh Arabs fled to Iran
Baroness Nicholson, who visited Marsh Arabs in Iran in early February 2003, said the psychological impact on them had been "total and devastating".
She said the Madan would not be able to return home unless Saddam Hussein was replaced by an administration which would allow the marshes to be re-flooded.
Even then it might be too late to restore more than half the marshlands, she said, and few of the refugees held out much hope.
"The Marsh Arabs I know are in a state of desolation and utter hopelessness. They have been treated as no human beings should be treated and virtually no one has done anything about it," she said.
"If the marshlands are not restored in the wake of the toppling of Saddam's regime, then the marsh people will fade into history, and our generation will be responsible for the deliberate extinction of one of the oldest races in the world," she added.