In the 1990s the Garden of Eden was destroyed. The fertile wetlands between the Tigris and Euphrates rivers were diked and drained, turning most of 15,000 square kilometers of marsh to desert. By the year 2000, less than 10 percent of that swampland--nearly twice as big as Florida's Everglades--remained. But reflooding of some areas since 2003 has produced what some scientists are calling the "miracle of the Mesopotamian marshes"--a return of plants, aquatic life and even rare birds to their ancestral home.

Curtis Richardson of Duke University and Najah Hussain of the University of Basra in Iraq have conducted the first ecological survey of the restored marshes. By September of last year, 39 percent of the original marshland was again underwater according to satellite photos. The natural rivers of grass had returned to these fragmented marshes and the scientists chose four to monitor: Al-Hawizeh (the only remaining natural marsh), Al-Hammar, Abu Zarag and Suq Al-Shuyukh. They found that by a host of measures, ranging from water quality to wildlife the marshes were returning to health.

Helped by increased snowmelt from the mountains of bordering Turkey and Iran, the reflooded marshes avoided high levels of toxins, heavy metals and other releases from the dry soil. As a result, vegetation is expanding to cover an additional 800 square kilometers per year. With vegetation, fish, crustaceans and other water creatures have returned, though not to historic levels. And bird species not seen in decades--such as the highly threatened Iraq babbler--have reappeared, part of a total of 74 returned birds.

This miracle's long-term viability is threatened, however, by increasing competition for the water itself. "In drought years, that is when the real crunch will come," Richardson notes. "They key is the water has to flow, it continually has to flush the system." With dammed irrigation projects in Turkey, Syria and Iran as well as increasing demands from Iraqi farmers, the marshes that cradled human civilization may get short shrift. "When Mother Nature was running it, the marshes used to get it all," Richardson adds. "My hope is that agriculture will work with the restoration effort and recycle some of that water." The ecosystem report appears in the current issue of BioScience.