Field studies in Iraq conducted during the past year suggest that some of the region’s ecologically devastated marshes could be restored, scientists reported at a meeting on Feb. 20.
As recently as the 1980s, a Connecticut-size swath of southeastern Iraq was a thriving marsh ecosystem. A 1984 census tallied about 75,000 people in the region, says Peter Reiss of Development Alternatives, a consulting firm based in Bethesda, Md. Many of those marsh Arabs lived in homes woven from 8-meter-tall reeds and made their livings by raising water buffalo and fishing.
Today, only about 7 percent of the area originally covered by the marshes remains intact, says Curtis J. Richardson of Duke University in Durham, N.C. A vast system of canals and dikes built along the Tigris and Euphrates Rivers under Saddam Hussein’s regime cordoned off most of the marshes, converting them into flat agricultural land.
Because evaporation vastly outpaces precipitation in the region, the fields quickly became poisoned with salt, says Richardson. Sediment once moistened by marsh waters now blows about in dust storms.
In late 2002 and early 2003, local residents breached some of the dikes and reflooded as much as 20 percent of the marshes, says Richardson. He and his team examined the 210-square-kilometer Abu Zarag marsh of central Iraq 18 months after its rehydration. The team found good water quality and a luxuriant growth of reeds.
Of the 40 species of plants that lived in the marsh before its drainage, 31 had returned in earnest. However, only a third or so of the fish species known to have lived there had made a comeback. Of those returning species, individual fish typically measured only half the size of their predrainage kin.
The researchers also observed that the ecological recovery is slow in many other reflooded areas. Salts leaching from sediments beneath the Suq Al-Shuyukh marsh make the water slightly brackish.
Reed growth there isn’t as lush as at Abu Zarag. The numbers of bird and fish species are about half those found in never-drained marshes nearby. More flushing with fresh water could reduce the salinity and improve recovery, Richardson says.
Richardson and Reiss presented their findings and plans for future study in Washington, D.C., at the annual meeting of the American Association for the Advancement of Science.
The percentage of Iraqi marshland that can be restored depends on how much fresh water can be diverted into the marshes. Large power-generating dams in northern Iraq are now impounding much of the water that could be used to nourish the wetlands, says Richardson.
Nevertheless, he estimates that current flow rates in the Tigris and Euphrates Rivers could be used to restore around 30 percent of the drained marshes to their former ecological health.