Iraq's southern wetlands are in crisis. These areas are the spawning ground for Gulf fisheries, a resting place for migrating wildfowl, and the source of livelihood for fishermen and herders who have called the marshes home for generations.
But drought that has stretched for two decades means less fresh water flowing into the marshes. As water levels fall, salinity goes up, leading to fish kills. The lack of fresh water has also pushed Marsh Arabs who own livestock - mainly cows or buffalo - to search for other sources of water.
Many families are leaving the area for other parts of Iraq. That poses a challenge to a society already wracked by war, says Hashim al Badran, director of the Agricultural Engineers Association of Basra.
"Then, it's sure, there will be conflict between them and other tribes about natural resources and it will cause security problems," he said.
The problem began with the building of dams upstream in the 1970s, and worsened when Saddam Hussein ordered the wetlands drained in the 1990s to punish the Marsh Arabs for the revolt against his rule. That, and the nearly 20 years of drought, are complicated today by the advance of the self-declared Islamic State.
"The war that is taking place in the north and west of Iraq against the terrorist groups, is happening in the areas that we call the large dams, like Mosul dam," al Badran observed. "Now it's a military zone and Haditha Dam in Ramadi is a military operation zone, in addition to dams in Ramadi and Falluja."
That gives the militants the ability to flood cities or withhold water.
An effort to restore the wetlands began after the 2003 U.S.-led invasion of Iraq. While herders can still find forage for their buffalo, and water deep enough for the animals to wallow in, and fishermen still cast their nets, vast areas of the marshland remain dried, cracked mud.
Fisherman Sayid Safaa says those who have stayed struggle to survive.
"The water is salty, our livestock died. We have to buy the water for our animals, spending 5,000 to 6,000 dinars a day, in addition to drinking water," he said. "All the fish in the marsh died. The water now is bad, all the families now are tired and frustrated about where to go. Some of them left and others stayed and are trying to fix the tragedy."
It is an environmental crisis that is evolving into a humanitarian one.