An internationally important wetland area of Afghanistan is now almost completely dry, the UN says.
"
We very badly want to restore eco-tourism
"
Dr Ahmad Yusuf Nuristani
Satellite imagery shows 99% of the Sistan wetlands, which stretch over the frontier into Iran, have dried out since 1998.
The Helmand river, which flows into the Sistan area, is running far below its normal level.
Afghanistan says it needs international help if it is to save the wetlands. The findings come from a study of Afghanistan undertaken by the Post-Conflict Assessment Unit of the United Nations Environment Programme (Unep).
Conflict damage
The unit's main report was launched in Kabul on 29 January, but details of the Sistan damage were given to Unep's governing council, meeting here until 7 February.
Dr Ahmad Yusuf Nuristani is Afghanistan's Minister of Irrigation, Water Resources and Environment.
He said: "The report makes it clear how conflict causes environmental destruction.
"Similarly, continued environmental depletion and scarcity of natural resources will cause further conflict. Effective environmental management is the key to breaking this vicious cycle."
Dr Nuristani said the Afghanistan Transitional Authority aimed to complete its first national budget by the end of March, and he was asking for nearly $20m for his ministry's environment work.
Important birds
The Unep report says the Helmand river, which drains 31% of Afghanistan's land area, has been flowing as much as 98% below its annual average in recent years.
But what Unep calls "uncoordinated management of the river basin's dams and irrigation schemes" during two decades of conflict have been worsened by four years of drought.
Lacking a stable water source, much of the Sistan basin's natural vegetation has died or been used for fuel.
This has increased soil erosion and the spread of sand on to roads, fields and settlements.
The wetlands used to be crucially important to birds.
In 1975 half a million waterfowl from 150 species were counted on Hamouni-e-Puzak, two-thirds of which lies in the Afghan part of Sistan.
They included eight globally threatened migrants like the Dalmatian pelican and the marbled teal.
Famous statues
In 2002, in central Afghanistan, Unep found the national waterfowl and flamingo sanctuaries at Dasht-e-Nawar and Ab-e-Estada were completely dry.
The critically endangered Siberian crane has not been seen at Ab-e-Estada since 1986. But there is some better news: Band-e-Amir, Afghanistan's first national park, is said to be "in good hydrological condition", supporting populations of ibex and urial (a species of sheep).
Although parts remain heavily mined, Unep says it offers significant potential for nature tourism.
Dr Nuristani told BBC News Online: "We very badly want to restore eco-tourism. It's one of the things we're planning most aggressively, and I hope it will be up and running in a year or two.
"We want visitors to come and see our endangered wildlife - species like the snow leopards, the markhor and the bears.
"And although it will be difficult, I think we'll be able to restore the Bamiyan Buddhas, the statues the Taliban destroyed in 2001."
The mines and unexploded ordnance littering parts of Afghanistan are an obvious deterrent to intending tourists, and also prevent Afghans from using good farming land.
But the assessment unit's chairman, Pekka Haavisto, said his team had found no sign of chemical contamination from the bombing campaign in the places it had visited.
It was the long years of conflict that appeared to have done the worst environmental damage, he said.